Questyle M15 · Mobile Lossless Headphone Amp with DAC


100+ Head-Fier
Best in slot
Pros: Balanced output: outstanding spatial reconstruction, spectacular instrument separation, great imaging, bilaterally extended, dynamic, powerful sound
Elegant, warm-ish musicality
Well implemented High Gain option
MQA full decoder (MQA fanbois can rejoyce)
Moderate host power consumption
Modest price for this sound quality
Cons: Single ended output: dull, compressed, underwhelming
Modest accent on midbass is a step away from tonal neutrality (some may find this not a con).
Easily picks up RFI when paired to a 4G-connected phone
No ASIO driver. No Direct DSD output support by Roon on Windows
Not fully supported by ALSA. No Direct DSD output support by Roon on Linux, either
After a very unfortunate first try (the review unit which was kindfully sent to me by the manufacturer was stolen at my door), I finally got an M15 unit which I quite oddly found for a very good price 2nd hand in Japan. This second package reached me regularly so I can finally assess this device which already collected convinced cobloggers' praises.

As there already is a comprehensive article about M15 on Audioreviews, I will entirely skip a general description of the device features as it would be needless repetition. I will also be succint on most sound impressions.

I'm going to focus on some detail which are not covered in the previous piece, and/or on aspects for which I have a different opinion.

M15 costs € 249 + freight on the manufacturer's website.

Miscellaneous good stuff and caveats

Good High Gain option

Unlike what happens on so many other devices I heard, M15's High Gain option is not chastising in terms of dynamic range compression. The effect is indeed very modest, which makes HG a totally viable option whenever one feels like adding some more early juice delivery to one or another driver.

Bad Single Ended output

It is so obviously duller and noisier compared to the Balanced option to be totally unworthy of such an otherwise outstanding product. To give a vague idea, it's roughly on quality level of M15's cheaper (120€) sibling, the M12 - which quality, at that price level, is trounced by the like of E1DA 9038D.

This means that one cannot elect the M15 as its "only" dongle if he/she has one or more drivers with single ended connections to support. Too bad.

Spectacular sound, if not totally uncolored

M15's sound is first of all grand (spatially), and immediately after that it's clear and detailed. Instrument separation and layering are just spectacular - which paired with its space drawing capabilities make for a really uncommonly good imaging and "sense of immersion" into the outcoming sound.

M15 is not uncolored in terms of tonality. There is some added accent on midbass notes - which is if you wish part of the "usual" compromise "musicality vs purity". The situation comes out obvious when comparing M15 with E1DA 9038SG3: the two offer equal bilaterally extended sound ranges, with the latter's bass staying faster, "more technical", therefore also "less expressive" in a sense.

9038SG3 is however a step under M15 in terms of spatial reconstruction, with particular regards to depth. Layering is also a bit less refined - and that's mainly why M15 comes across overall "more musically pleasing" compared to 9038SG3.

Powerwise 9038SG3 is better vs very low impedances: in the E5000-acidtest 9038SG3 beats M15 in terms of bass control and overall clarity. It's fair to observe that 9038SG3 remains the best option around, and by far so, when the available budget is like half M15's asking price.

In its being "exquisitely musical if unpure" M15 can't but recall Groove in a sense. In Apogee's dongle case sound colouring is even more marked, and comes with furtherly higher capability in terms of stage drawing - depth and height most of all. The two devices are not effectively comparable though - mainly due to Groove's internal architecture making it the odd ball it is - read my piece for the full reasons why.

Annoying RFI sensitivity

When paired to a smartphone connected to the 4G cell network M15 easily picks up RFI (Radio Frequency Interference) when within approx 10cm from the phone. The "solution" is using a non-ultrashort USB-C cable for the connection, but a problem still remains when you walk around with your phone + the M15 in a coat's pocket...

By comparison, E1DA 9038D behaves very similarly, E1DA 9038SG3 is instead virtually immune to such RFI.

Oddly lacking Direct-DSD support on non-mobile OS

While M15's USB interfacing is fully supported by Android, not the same happens when the device is plugged onto a Windows or Linux host.

For Windows, Questyle does not make an ASIO driver available (yet?). M15 can therefore be used only on "WASAPI Exclusive" mode. Which means there's not way to have access to direct DSD transfers (Wasapi only supports PCM).

For Linux the situation is even wierder (if not unique). M15 is apparently not fully supported by standard ALSA (Advanced Linux Sound Architecture) and the end result is that Roon Bridge on a Linux server does not offer Direct DSD support onto M15 when locally connected to it. Not the first time it happens to me - 9038D and 9038SG3 suffer of the same issue.

Considerations & conclusions

It's very simple: Questyle M15 is "the" DAC/AMP dongle to have if one has 250-300€ to spend, and has balanced connectivity options for all its drivers.

It's got superb sound clarity and body, very good spatial reconstruction capabilities, very good power management and strong power output.

In terms of overall sound experience M15 easily beats all standalone budget and mid-tier DAPs I happened to audition or own, the ones starting to represent an evident upgrade to it being nothing short of Questyle's own QP1R, or Lotoo's Paw 6000 and Gold Touch, or Cayin's N8. Seen from this angle M15 carries a very reasonable price tag.

The sole serious caveat to mention for me about M15 is its Balanced output option being the sole one delivering good quality. Whoever wants or needs a Single-ended source wouldn't be as satisfied with M15 (and its price).

M15 is rightfully stuck on Audioreviews' WoE, and determines the passage of Earmen Sparrow and L&P W2 to the relevant Past Excellences section therein.

This article originally appeared on, here.
Last edited:
Why does the balanced output sound so much better than the single ended?
It doesn't. I have the M15 and the balanced output is just louder. In fact, I think I prefer single ended output with IEMs. AND, the single ended sounds significantly better than the output of the M12, which I also have.
As you mentioned the bad SE output. Can I connect the M15 with a 4.4 mm to RCA cable to my desktop headphone amp to get full potential?


100+ Head-Fier
Questyle M15 | Super Short Sound Review | Speaker? Yes! Headphones/IEMs? Nah
Pros: + Great dynamics, confident & powerful
+ Sheer microdetail retrieval
+ Digs deep into recording, reveals tonal shifts well
+ Unlocks previously hidden technical ability of whatever is plugged into it
+ 3.5mm output is 99% as good as 4.4mm output
Cons: - Very narrow, cramped soundstage dimensions
- Overly analytical, distant sound presentation, unengaging
- Introduces "sonic walls" for headphones and IEMs, the opposite of immersive
- Needs to be paired with something warmish or the end result will sound clinical & artifical indeed
The Questyle M15 is great for active speakers but I do not like it for headphones/IEMS. I find it sounds overly sharpened & almost unnatural. There is no reason for it to sound as cramped as it does. Anyone who uses this when reviewing headphones/IEMs and say they find the stage to be only okay or small - don't trust it. This thing imparts its own flavour and shrinks the stage. The absolute majority of people want immersiveness for headphone/IEM listening and this is antithetical to that effect.
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It’s amazing how you convey all the necessary info in such a short review ( and destroy my curiosity for M15 in the process) :dt880smile:
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I'm glad I could help you save some time and money. I've tried many dongles at this point. The M15 is my least favorite, even though I admit it has the best detail so far.

My absolute recommendation is the me Xduoo Link2 Bal which has THE widest stage and most immersive sound out of all dongles I've tried.


100+ Head-Fier
Ending 2022 on a very good note!
Pros: Sound, aesthetics, build quality, performance...
Cons: Price (depending on your budget)...

The Questyle M15 has been sent to me by Questyle in exchange for the publication of this review. No specific requests or comments have been made and, as always, I will aim to be as sincere and unbiased in my review as is humanly possible.
You can find the official page for the M15 here:

As always, this is a non affiliate link.



As this is going to be my last review of 2022, I wanted to end the year on a positive note, therefore, although I have been using the M15 for a while, I have saved the review until now. That is already an indication of what I think about the M15 but I am going to explain in detail what it is that has drawn me into this little (depending on what we compare it to) dongle.

Earlier in the year I reviewed the CMA15, which was (is) an amazing product, offering a lot in a single package even if the price is not exactly budget friendly (depending on your budget of course, there are much more expensive things out there).

Around the same time, Questyle launched the M15, a small dongle that is powered by USB from the host device, which got a lot of favourable opinions. I didn’t get a chance to try it out at the time that it was recently launched and to be honest, while I was interested, I really was not in need of a dongle style DAC. As you all know, my main portable set up is the iFi Gryphon, with the Go Blu being my pocketable option and when I really need to go smaller, well, I have a bunch of Apple dongles stored in all kinds of places which do the job.

I did try out a few other dongles, the most notable probably being the S9 Pro and the iFi Go Bar, and while I liked the Go Bar, I didn’t really feel that it gave me anything that I didn’t already have.

Fast forward some months and Questyle very kindly offered to send me the M15 and I was happy to give it a try. As a fan of the CMA15, I was interested to see what the brand could offer at the other end of the scale, in a tiny package that retails for just under 235€ (at the time of writing this review). Now that is not exactly a budget offering either (although it is a little cheaper than the iFi Go Bar) and I expected it to be good, but I wasn’t really counting on liking it as much as I actually do.

So, enough rambling for this year, let me get on with my last review of 2022 and explain what it is that I like about the Questyle M15.



There is nothing really notable about the presentation of the device. It arrives in a small black box, well protected by the foam surround, and the only other accessory is a short (well made) USB-C to USB-C cable. As I said, nothing really to mention.

What is worth mentioning is the protective cover that Questyle included in a separate small box (this one white) and is available as a pack on their website for no extra cost (again, at the time of this review). The sleeve is made of leather and is available in a selection of colours, the one I received being light brown (something I am fond of).


Build and aesthetics…

While the build quality seems to be very good, where the M15 stands out from the rest is in aesthetics. One side of the unit there is a transparent window that allows us to see the internals of the unit, that is the circuit board etc. While seeing a circuit board may not sound like much of a big deal, I like it, and it also stops us wondering about what level of workmanship may be inside the device. They also mounted the indicator LEDs on the board so they are visible through the window.

As far as the case, it is also very well built and has an open side to it, allowing us to still see through the window of the device. It is a very good fit and protects the device well, except for the open side of course. I am not sure how the window will stand up to scratches over time but I’m sure it would be easy enough to adapt a small piece of glass protector if it is something that worries you.

There is also a cut out on the side of the cover which allows easy access to the gain switch. This is something simple enoguh but not all brands actually take it into consideration.



There really isn’t anything complex about the M15 that would need explaining, but let’s go over it briefly anyway.

On the bottom of the unit we have the USB-C connector which is where our source device connects. On the side, we have the gain switch that slides to either low or high gain. On the top of the device we have a 3.5mm unbalanced output, together with a 4.4mm balanced output.

There are two LEDs on the circuit board that are visible via the transparent window. The first shows the set gain level (green for low and red for high). The second, which will only light up when the device is playing and has earphones connected, shows us the format of the file we are listening to, green indicates 48kHz or less, red indicates 88.2kHz PCM (or above) and DSD64 to DSD256.

That is it. Not much to explain.

I have tried the M15 on multiple Android devices and on multiple PCs and while there was an issue with MQA playback on Android at first, an update to Tidal fixed the issue, so the blame can obviously be directed at Tidal.

One thing I have found as an issue is that, when using the M15 connected to a Windows 10 PC (I don’t have any 11 machines, thankfully 😉 ) and running Tidal in exclusive mode, each time there is a track change, the volume jumps to 100%. This is something that could be a problem and I recommend that you either avoid Tidal in exclusive mode on PC or at least try it without your favourite IEMs connected (and certainly not in your ears) to see if it happens also on your machine. I think this is something related to the Tidal software as it has not happened to me with any other media player software (nor with Tidal on Android) but is certainly worth being aware of.



Judging the sound of a good device (and the M15 is certainly that) is something that I find difficult, as I can never be 100% sure of what I am actually hearing and what is just something that my brain thinks I am hearing. I have said many times that the brain is the most important part of audio, as we can not only interpret things in a different way, but can also experience things that may not actually be there.

Yes, it is possible to do triple blind ABX tests to see if we can really notice a difference between two amplifiers or DACs, and I have no doubt that the vast majority of us would fail, but at the end of the day, listening to music is about enjoyment (at least for me). That means that if I am listening to something and I really enjoy the sound, then I really don’t care if 95% of the sound is just my brain telling me that I am hearing what I want to hear, I mean, at the end of the day, I am doing just that, hearing what I want to hear.

In the case of the M15, I have been using it with quite a few sets of IEMs that I have been testing over the past weeks, plus some more that I will review soon, and I have to say that I really enjoy what the M15 has to offer.

It may not be the most powerful of devices, although I do not have measurements, but in comparison to the Go Bar, it does seem to have a lower output level. However, for IEMs, I have not found that any of the IEMs I have tested via the SE output have needed me to switch to high gain, much less in balanced mode.

As an example, I have mainly been using the M15 connected to my android tablet, using UAPP, and my usual listening levels have been between -24dB and -26dB (depending on track and IEMs used), so plenty of power left. With planar IEMs, such as the Talos or S12, I have been using the balanced output but have not noticed any lack of power or performance with these IEMs.

It also does a decent job with over ears, especially easier to drive ones. With the HD6XX I was very pleasantly surprised with how well they work with the M15. I wouldn’t say that it is the best I have ever heard from the HD6XX (it won’t be replacing the Feliks) but it is plenty for my listening levels and the performance is better than a lot of other options I have tried with these headphones. With more difficult to drive planars, such as the Arya v2, it again reached my listening levels without issue, although I don’t feel that it was quite capable of driving them to the best of their abilities (which is to be expected from a dongle).

The sound itself I find to be extremely detailed but never harsh. Now, as I already said, these are completely subjective opinions, so take that for what you will, but in comparison to my main IEM set ups, the Gryphon and the Go Blu, I find that the M15 seems to be a little more airy, giving a sensation of more detail and a little less warmth.

However, even if it presents less warmth than the iFi options, it still stays a long way from being harsh or cold, something that I did find with the S9 Pro for example. The S9 Pro I also found to be something that potrayed lots of details, yet at the same time, I got the sensation that the details sounded forced, as if they were being pushed at you. The M15 gives me no such sensation, is presents the details in a way that they are very easy to focus on but never seem to be “in your face”.

With IEMs that can have a little bit of harshness in the higher ranges, or with tracks that are also on the harsh side, I don’t find that the M15 adds any extra harshness at all. With tracks and IEMs that are on the other side of the scale, a little too warm (or even bloaty) in the low end, I find that the M15 actually seems to tighten it up a little, without actually removing quantity.

If I had to explain the overall sound of the M15 in one sentence, it would be “clean, neutral, natural and smooth”.



As I said at the beginning of this review, I wanted to end 2022 on a positive note and the experience I have had with the M15 is nothing but positive. I have paired it with a lot of different combinations and while it wouldn’t be my first choice for power hungry over ears, for everything else I have found that it is just a wonderful little device.

I am someone who prefers cables when possible and while I really enjoy the Go Blu for what it gives me in a bluetooth package, when connected by cable, I much prefer the M15, at least for the IEMs that I use regularly (and those that I have been testing) with the music that I listen to.

It is not going to replace the Gryphon as my main test device for reviews, as the Gryphon has (apart from great sound) so many other functions that make it a perfect (trans)portable device. However, for a compact device that provides excellent sound, the M15 is going to become a main part of my listening experience on the go (or even just relaxing on the sofa).

Therefore, with the Sennheiser IE600 connected to the Questyle M15 and my favourite albums, I conclude my reviews of 2022 in the best way possible!


As always, this review is also available in Spanish both on my blog ( and on YouTube (
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I also use M15 with ie600(4.4), ie100PRO(3.5), Nuemann NDH20 (3.5 soon arrive balanced cables so will try with 4.4 port) same goes for Sennheiser HD650. I also have Xduoo link2 bal max (new version), Hiby FC4 and apple dongle 3.5mm have heard my gear on my Topping L30ii and other dongles but M15 is by far the best I have ever heard especially with Sennheiser IE600 it is PERFECT MATCH.
About the M15 beside it is almost perfect dongle dac/amp there are some issues
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1. With Tidal is very hard to adjust volume especially in "Exclusive mode" it is pain in the a** and if you not use "EM" there is not MQA or at least magenta light just red or sometimes even green.
2.Sometimes also on Tidal in "EM" you will get red light on one song other time just green (Same song same playlist) and when switch to "System controlled" output from green goes to red but than there is not magenta on MASTER track
so it is bit confusing and annoying all this on both windows laptops one run 10pro other 11 so doesn't matter. On iPhone everything functioning perfect green is green red is red magenta is magenta simply no problem at all.
Now the interesting thing.
Both Neumann NDH20 (150 Ohms) & Sennheiser HD650 (300 Ohms) sound better on M15 (High Gain) than Topping L30ii paired with Marantz PM7000N (Asahi-kasei AK4490EQ DAC) thru QED Performance Audio Graphite RCA cable and Marantz PM7000N thru its own 6.35 output directly. No matter iPhone or Laptop connected and all that on SE 3.5 I just could imagine the difference when balanced cables for both headphones arrive :)
Xduoo link2 bal max and Hiby FC4 also very good dac/amp but Questyle M15 is from another planet and worth every penny. whatever you put on M15 it sounds much much better than anything you have heard before.
I'm really considering to order extra few just to have peace of mind if anything happened with it in future or Questyle simply discontinue this model :D
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Reviewer at hxosplus
Divine current on the go
Pros: + Musical and organic sounding
+ Realistic timbre and minimum digital glare
+ Excellent technicalities
+ Crystal clear and transparent
+ Dynamic and impactful
+ Dead silent and free of EMI noise
+ Can drive efficient headphones
+ Low power consumption
+ Stays cool even after hours of use
+ Unique appearance
+ Excellent build quality
Cons: - Lack of on-board volume control and hardware buttons
- Not as powerful as the competition
- Carrying case and lightning cable are extra
- Bright LEDs
The review sample was kindly provided free of charge in exchange for an honest review.
I didn't receive monetary or any other kind of compensation and I don't use affiliate links.
The price of the M15 is $249 and you can order it directly from Questyle shop or all authorized dealers around the world.


Questyle Audio is dedicated to the research of high-tech lossless audio systems with perfect sound aesthetics and convenient listening experience, and provide the corresponding products, system solutions or key components according to customer requirements.
They are famous for their Current Mode Amplification topology that uses current, instead of voltage, to amplify audio signals.
Their CMA Fifteen is one of the most awarded and well regarded all-in-one systems thanks for its unparalleled performance as you can find out by reading the related review.
After finishing the CMA Fifteen review I was very curious to find out how the Current Mode Amplification performs in a portable device so I contacted Questyle who were very responsive and kind enough to arrange a sample.


Questyle M15

The Questyle M15 is a USB DAC/amp dongle containing two of Questyle’s patented CMA (Current Mode Amplification) SiP modules, for a total of four CMA amp engines.
This quadruple drive amplification circuitry gives an outstandingly strong output that can drive almost any headphone.
Questyle’s Current Mode Amplifiers are characterized by their small footprint, low voltage operation, and minimal power consumption.
Current Mode amplification has a naturally low impedance, affording the M15 a bandwidth up to 1MHz and distortion as low as 0.0003%.


The M15 supports both unbalanced (3.5mm) and balanced (4.4mm) outputs with a manual gain adjustment via the slider on the side, which makes it easy to choose high/low gain depending on the connected headphone.
The M15 features the highly acclaimed ESS ES9281AC flagship DAC chip to do the decoding and can handle up to PCM384kHz/32bit, DSD256 and full MQA unfold.
The M15 also uses a TOREX, high-efficiency, power management unit for low power consumption from the host device without getting overheated.


Appearance and build quality

The M15 has a minimalistic design with a black metal housing that is made from CNC machined aluminum and a transparent glass cover which allows for the internal PCB to be fully visible.
A very innovative design that differentiates the M15 from the competition giving it a uniquely looking appearance.
Build quality and finish are excellent, there are no rough edges or sharp corners but I have some reservations about the durability of the glass.
The 61.8x27.2x12mm measuring M15 is compact and lightweight, at least for a dongle with two headphone outputs.


User interface

This is a simple to operate device, no drivers are needed, the only thing you have to do is to plug it to the host device with the supplied detachable cable to the USB type-C port and then your headphones to either the single ended or balanced outputs.
The device will power itself only when a headphone is plugged in so you can leave it hanging from your phone without consuming power if you have your headphones unplugged.

The M15 is lacking an on-board volume control so you are restricted to your phone's steps for volume adjustment which is not that ideal.
Inside the unit and close to the USB port there are located two indicator LEDs that are quite bright.
One is for displaying the sample rate (Green ≤ 48kHz, Red>48kHz or DSD and Magenta for MQA) and the other for the gain (Red=high, Green=Low).



Inside the box you are going to find two short USB cables of high quality.
USB-C to USB-C and USB-A to USB-C.
A lighting cable and a premium leather case are available as extra purchases.


Power output

The M15 was left playing music for about 100 hours in order to settle down.
During the evaluation period I used various headphones and earphones like the Focal Clear Mg, Sennheiser HD660S, Meze 109 PRO, FiiO FDX and Unique Melody Mext.
All headphone cables are from pure silver made by Lavricables.

With a maximum output voltage of 1.895Vrms from the 3.5mm jack and 2.624Vrms from the 4.4mm, the M15 is not the most powerful dongle when considering that most of the competition can usually do 4Vrms from the balanced output while the iFi Go bar can go as high as 7.5Vrms.
But sometimes lab measurements can be deceiving and the truth is that the M15 provided plenty of juice for driving efficient headphones like the Focal Clear Mg and the Meze 109 PRO.
Background noise is pretty inaudible and the M15 is well shielded so it doesn't pick electromagnetic interference.
The M15 stays completely cool even after hours of continuous use and it has a relatively low power consumption.


Listening impressions

Plain and simple, the M15 is the most naturally sounding ESS dongle that I have reviewed so far with the less (if not completely absent) digital glare while retaining all of the famous ESS transparency and excellent technicalities.
It seems that the "current mode amplification" modules are making a great job into producing a very musical sound signature with an analogue-like and organic timbre.

Listening with the M15 is an enjoyable and engaging experience that is characterized by the surplus of musicality.
The tonality is realistic with plenty of colorful overtones that help instruments and voices to sound harmoniously intense and complete.
At the same time the M15 is a competent technical performer with supreme fidelity, absence of coloration and frequency response irregularities, petty thundering dynamics, excellent resolution and crystalline clarity.
There is no kind of music that is not suitable for the M15 while headphone matching is really not an issue because the M15 makes sure that you are listening to your headphones and not the device itself.

The bass is deeply imposing, fast, precise and controlled with excellent layering and definition.
The texture is not too visceral but not lean either, balanced would be the word to use while dynamics sound contrasted and impactful.
Mid-range consistency is great; the sound is coherent and articulated with a lush and rounded texture without becoming warm or romantic.
This is the part of the frequency range that has the richest harmonies and the purest timbre helping instruments and voices to sound very alive and close to reality.


The treble extension is amazing, the M15 is lively and sparkling sounding with excellent detail retrieval and plenty of airiness but without any of the brightness and forwardness that are usually associated with most ESS DAC implementations.
Smooth enough, without sharpness or edginess and very controlled when it comes to digital glare, the M15 is the kind of DAC that is heartily recommended for all day listening without causing treble fatigue.

The soundstage, given that you have the right headphone, can become very speaker-like at least as far as a dongle can go.
It is grand sized with sharp imaging and tactile arrangement of the performers with plenty of spatial information and natural reverb.
The listener feels like sited in the second row of the concert hall making the M15 ideal for listening to large scale symphonic and choral works.


Compared to the iFi Go bar ($329)

I consider the iFi Go Bar (and the Cayin RU-6 ) the references when it comes to musicality and organic timbre so a comparison, with at least one of them, was pretty inevitable.
Comparing the Go bar with the M15 proved that are on the same league of musical presentation with some minor differences.

The M15 has the lead in technicalities because it offers better clarity, it sounds more defined and resolving, it has faster transients, more contrasted dynamics and impactful bass.
But it sounds relatively drier when compared the more organic, tube-like and fuller sounding Go bar.
Additionally the Go bar feels more relaxed and loose around the notes, not as fast and not that firm or controlled.
The Go bar has a more holographic soundstage presentation but the positioning of the listener is closer, more intimate, almost next to the performers.


On the non-audio related stuff, it is the minimalistic M15 against the full featured Go bar which offers four digital reconstruction filters, XBass+ and XSpace analogue processing modes and iEMatch.
The Go bar has also an on-board volume control and physical buttons and it is more powerful than the M15 but with the disadvantage that it is not that power efficient.
The Go bar is about $80 more expensive than the M15 but the package includes a lighting to USB-C cable and a carrying case.


In the end

The Questyle M15 is not only the most uniquely looking USB DAC dongle among the competition but is also the most uniquely sounding because it manages to combine top level technicalities with the most musical and organic sounding character almost surpassing every other USB DAC dongle.
Very efficient and simple to use, the only thing you have to do is to plug your headphones and let be carried away by the divine current into the most musical adventure.

Test playlist

Copyright - Petros Laskis 2022.


New Head-Fier
𝐐𝐮𝐞𝐬𝐭𝐲𝐥𝐞 𝐌𝟏𝟓: Deus Ex Machina
Greetings! 💨🦖

This is a review of the Questyle M15, which Questyle themselves have provided me to review.



This review for the Questyle M15 marks Goji’s debut in reviewing a series of gear that can be considered as an audiophile’s best friend: the dongle. This debut in starting to review dongles has been grandiose so far: the Questyle M15 is an absolute god when it comes to outputting every song you throw at it in the clearest and most beautiful way possible. It has the power to push most IEMs to their upper limits, resulting in a very versatile experience, no matter how huge your collection is. I couldn’t describe any faults with how good the M15 is, as long as you have the pocket/wallet depth that it requires.

$249.99 (USD)
~₱14,254.80 (PhP)

𝙏𝙚𝙘𝙝𝙣𝙞𝙘𝙖𝙡 𝙎𝙥𝙚𝙘𝙞𝙛𝙞𝙘𝙖𝙩𝙞𝙤𝙣𝙨
𝗢𝗽𝗲𝗿𝗮𝘁𝗶𝗻𝗴 𝗦𝘆𝘀𝘁𝗲𝗺 𝗥𝗲𝗾𝘂𝗶𝗿𝗲𝗱:
- Android phone and pad: Android 5.0 and above;
- Apple cellphone: iOS
- Apple computer: mac OS
- PC: Win10 1803 and above;
𝗗𝗔𝗖:ESS flagship USB DAC chip ES9281AC
𝗗𝗔𝗖 𝗖𝗮𝗽𝗮𝗯𝗶𝗹𝗶𝘁𝘆:
- PCM:PCM: 32kHz – 384kHz (16/24/32Bit)
- DSD: DSD64(1Bit 2.8MHz) , DSD128(1Bit 5.6MHz), DSD256(1Bit 11.2MHz)
𝗢𝘂𝘁𝗽𝘂𝘁 𝗣𝗼𝘄𝗲𝗿:
- 3.5mm:RL=300Ω,Po=11.97mW, Vout(Max)=1.895Vrms,THD+N=0.00045%
- 4.4mm:RL=300Ω,Po=22.60mW, Vout(Max)=2.624Vrms,THD+N=0.00057%
𝗧𝗼𝘁𝗮𝗹 𝗛𝗮𝗿𝗺𝗼𝗻𝗶𝗰 𝗗𝗶𝘀𝘁𝗼𝗿𝘁𝗶𝗼𝗻:0.0003%
𝗣𝗹𝘂𝗴 𝗧𝘆𝗽𝗲: 3.5mm unbalanced, 4.4mm balanced

𝙋𝙖𝙘𝙠𝙖𝙜𝙞𝙣𝙜 💨💨💨💨🦖 (out of 5)

➡️ Presentation
The box of the Questyle M15 isn’t that extravagant nor far-reaching as the likewise-priced IEMs that I have unboxed in the past, but this one mean business right away. The packaging does not follow any trends in Chi-Fi; it really looks like it came from a big name in the industry in terms of how professional and elegant the packaging is. It does not flood the consumer with any grandiosity: it just means business. That’s how you say that the Questyle M15 will surely give its listener the best experience possible.



➡️ Product
After a layer of paperwork, we are presented right ahead with the Questyle M15 in all its glory. There is just a layer of protective plastic covering the huge window for one to see the internals of the dongle, and it’s nothing short of breathtaking to see. It’s like looking at a McGuffin in futuristic sci-fi film, destined to carry some sort of data that holds the fate of the universe. Questyle’s logo is emblazoned on the rear side of the dongle, printed out in a minimalist yet recognizable way. There are no other visual flairs here and there in this product. Tt just focuses you look at the main attraction: the beautiful internal hardware that powers the beast.


➡️ Particulars
After the layer that houses the dongle itself, the final one contains two cables: USB-C to USB-A and USB-C to USB-C. The dongle itself terminates at a USB-C port, so this is more than enough for one to use for his/her smartphone and PC needs. Questyle also graciously provided me with an extra cloth bag for travel and a USB-C to Lightning connector, which was helpful as I have an iPhone 6 Plus as my main phone as of the moment. The particulars may be spartan, but it’s more than enough to handle my own personal use of it from the gears that I have.


𝘽𝙪𝙞𝙡𝙙 𝙌𝙪𝙖𝙡𝙞𝙩𝙮 💨💨💨💨💨🦖 (out of 5)
I haven’t tried out dongles before, but I have seen and handled many in the past years that I have been in this hobby. Let me tell you, the build of the M15 is just immaculate. There are no seams nor awkward connections that line the entirety of the product. The reason why I mentioned seams and connections is that those can easily open when an item is dropped. Any form of them is a structural weakness in any gear, even in IEMs. In lieu of this, the M15 is built like a small tank, able to take falls or hits without any hitch. It also has reliable plugs that provide that satisfying hefty click when you insert your 3.5mm or 4.4mm termination in it, ensuring that you have properly connected your audio gear into the dongle. It can be just a little bit awkward at first as it connects deeper than your ordinary smartphone or PC port, but it’s easy to get used to. I have also seen some reports of the switch for the low/high gain malfunctioning for some of those who own the M15; I haven’t personally experienced it in the few months that I’ve used it extensively. It still feels just as sturdy and as reliable as the first day I have got it, and never malfunctioned on me since.






𝙐𝙄 (𝙐𝙨𝙚𝙧 𝙄𝙣𝙩𝙚𝙧𝙛𝙖𝙘𝙚) 𝙖𝙣𝙙 𝙀𝙖𝙨𝙚 𝙤𝙛 𝙐𝙨𝙚 💨💨💨🦖(out of 5)
I have had the chance to extensively use this dongle for a few months after writing this review, so I really had the time to experience every nook and cranny that the M15 offered to its user. First things first: this is definitely NOT for travel or outdoor use. The entirety of the dongle may seem small when you first handle it, but it is extremely clunky when you try to have a portable experience from it by inserting it to your chosen device and going out while it’s located in your pocket. This can be slightly solved by purchasing a longer cable to connect it to your device, but it results in a tangly experience that is also clunky to experience outdoors. The Questyle M15 is meant to be used indoors or in a more relaxed travelling environment (in a private car, in an airplane flight, etc.) because of its size in conjunction with its purpose as an extension of your device. But once you get the hang of it, you’ll realize its situational use and plan out your excursions accordingly.

On the other hand, the M15 easily connects to any device that I plug it in: may it be in my Samsung smartphone (Samsung Galaxy S8+), iOS (iPhone 6 Plus, iPhone X, iPad mini), and PC (HP Pavillion x360). It automatically detects the dongle AS LONG AS a gear is plugged into any of the inputs (3.5/4.4), as devices sometimes fail to recognize the M15 in situations when there is no gear attached to it. It already comes with software that’s compatible with most devices, though you have the choice to update its software version with an installer and data available on Questyle’s official website. Some said that there are changes in the sound signature of the M15 when it is indeed updated, but I cannot confirm nor deny it. I honestly didn’t perceive any noticeable differences, but if there is, it’s to the point that isn’t worth noting. The LEDs on the device also seamlessly switch between colors depending on the gain (low=green, high=red) and the file type/bitrate being processed (green=48kHz or less, red=PCM/DSD, magenta=MQA final unfolding). I have tested this out as I have file types of different kinds (MP3s, FLACs, DSD/PCMs, and Tidal for MQA), and it corresponds correctly to the files I throw at it.


A gripe that I have with the M15 can be seen in its lack of any other options in terms of hardware switches/buttons rather than the low/high gain option. This would’ve benefitted from the addition of a volume button/rocker and a play/pause button as complimentary to the low/high gain switch. However, these decisions may have been scrapped to allow for the nice circuitry on display that is present on this device.

𝙎𝙤𝙪𝙣𝙙 💨💨💨💨💨🦖 (out of 5)


𝘋𝘢𝘧𝘵 𝘗𝘶𝘯𝘬 - 𝘙𝘢𝘯𝘥𝘰𝘮 𝘈𝘤𝘤𝘦𝘴𝘴 𝘔𝘦𝘮𝘰𝘳𝘪𝘦𝘴 (𝘢𝘭𝘣𝘶𝘮)
𝘋𝘢𝘧𝘵 𝘗𝘶𝘯𝘬 - 𝘈𝘭𝘪𝘷𝘦 2007 (𝘢𝘭𝘣𝘶𝘮)
𝘋𝘢𝘷𝘪𝘥 𝘉𝘰𝘸𝘪𝘦 - 𝘉𝘭𝘢𝘤𝘬𝘴𝘵𝘢𝘳 (𝘢𝘭𝘣𝘶𝘮)
𝘋𝘶𝘢 𝘓𝘪𝘱𝘢 -𝘍𝘶𝘵𝘶𝘳𝘦 𝘕𝘰𝘴𝘵𝘢𝘭𝘨𝘪𝘢 (𝘢𝘭𝘣𝘶𝘮)
𝘛𝘸𝘪𝘤𝘦 - 𝘔𝘰𝘳𝘦 & 𝘔𝘰𝘳𝘦 (𝘢𝘭𝘣𝘶𝘮)
𝘛𝘸𝘪𝘤𝘦 - 𝘌𝘺𝘦𝘴 𝘞𝘪𝘥𝘦 𝘖𝘱𝘦𝘯 (𝘢𝘭𝘣𝘶𝘮)
𝘔𝘪𝘤𝘩𝘢𝘦𝘭 𝘑𝘢𝘤𝘬𝘴𝘰𝘯 - 𝘋𝘢𝘯𝘨𝘦𝘳𝘰𝘶𝘴 (𝘢𝘭𝘣𝘶𝘮)
𝘕𝘦𝘸 𝘖𝘳𝘥𝘦𝘳 – 𝘛𝘖𝘛𝘈𝘓 (𝘢𝘭𝘣𝘶𝘮)
𝘕𝘦𝘸 𝘖𝘳𝘥𝘦𝘳 - 𝘗𝘰𝘸𝘦𝘳, 𝘊𝘰𝘳𝘳𝘶𝘱𝘵𝘪𝘰𝘯, 𝘢𝘯𝘥 𝘓𝘪𝘦𝘴 (𝘢𝘭𝘣𝘶𝘮)
𝘗𝘰𝘳𝘤𝘶𝘱𝘪𝘯𝘦 𝘛𝘳𝘦𝘦 - 𝘐𝘯 𝘈𝘣𝘴𝘦𝘯𝘵𝘪𝘢 (𝘢𝘭𝘣𝘶𝘮)
𝘗𝘰𝘳𝘤𝘶𝘱𝘪𝘯𝘦 𝘛𝘳𝘦𝘦 - 𝘍𝘦𝘢𝘳 𝘰𝘧 𝘢 𝘉𝘭𝘢𝘯𝘬 𝘗𝘭𝘢𝘯𝘦𝘵 (𝘢𝘭𝘣𝘶𝘮)
𝘚𝘭𝘦𝘦𝘱 - 𝘏𝘰𝘭𝘺 𝘔𝘰𝘶𝘯𝘵𝘢𝘪𝘯 (𝘢𝘭𝘣𝘶𝘮)
𝘚𝘭𝘦𝘦𝘱 - 𝘛𝘩𝘦 𝘚𝘤𝘪𝘦𝘯𝘤𝘦𝘴 (𝘢𝘭𝘣𝘶𝘮)
𝘖𝘮 - 𝘈𝘥𝘷𝘢𝘪𝘵𝘪𝘤 𝘚𝘰𝘯𝘨𝘴 (𝘢𝘭𝘣𝘶𝘮)
𝘊𝘢𝘯𝘥𝘭𝘦𝘮𝘢𝘴𝘴 - 𝘌𝘱𝘪𝘤𝘶𝘴 𝘋𝘰𝘰𝘮𝘪𝘤𝘶𝘴 𝘔𝘦𝘵𝘢𝘭𝘭𝘪𝘤𝘶𝘴 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘦𝘭𝘭 𝘞𝘪𝘵𝘤𝘩 - 𝘔𝘪𝘳𝘳𝘰𝘳 𝘙𝘦𝘢𝘱𝘦𝘳 (𝘢𝘭𝘣𝘶𝘮)
𝘗𝘢𝘭𝘭𝘣𝘦𝘢𝘳𝘦𝘳 - 𝘏𝘦𝘢𝘳𝘵𝘭𝘦𝘴𝘴 (𝘢𝘭𝘣𝘶𝘮)
𝘋𝘦𝘢𝘧𝘩𝘦𝘢𝘷𝘦𝘯 - 𝘚𝘶𝘯𝘣𝘢𝘵𝘩𝘦𝘳 (𝘢𝘭𝘣𝘶𝘮)
𝘋𝘦𝘢𝘧𝘩𝘦𝘢𝘷𝘦𝘯 - 𝘖𝘳𝘥𝘪𝘯𝘢𝘳𝘺 𝘊𝘰𝘳𝘳𝘶𝘱𝘵 𝘏𝘶𝘮𝘢𝘯 𝘓𝘰𝘷𝘦 (𝘢𝘭𝘣𝘶𝘮)
𝘒𝘰𝘳𝘯 - 𝘒𝘰𝘳𝘯 (𝘢𝘭𝘣𝘶𝘮)
𝘒𝘰𝘳𝘯 - 𝘓𝘪𝘧𝘦 𝘐𝘴 𝘗𝘦𝘢𝘤𝘩𝘺 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘭𝘢𝘤𝘬 𝘛𝘰𝘯𝘨𝘶𝘦 - 𝘕𝘢𝘥𝘪𝘳 (𝘢𝘭𝘣𝘶𝘮)
𝘋𝘦𝘢𝘵𝘩 - 𝘏𝘶𝘮𝘢𝘯 (𝘢𝘭𝘣𝘶𝘮)
𝘋𝘦𝘢𝘵𝘩 - 𝘚𝘺𝘮𝘣𝘰𝘭𝘪𝘤 (𝘢𝘭𝘣𝘶𝘮)
𝘋𝘦𝘢𝘵𝘩 - 𝘛𝘩𝘦 𝘚𝘰𝘶𝘯𝘥 𝘰𝘧 𝘗𝘦𝘳𝘴𝘦𝘷𝘦𝘳𝘢𝘯𝘤𝘦 (𝘢𝘭𝘣𝘶𝘮)
𝘕𝘪𝘨𝘩𝘵𝘸𝘪𝘴𝘩 - 𝘖𝘯𝘤𝘦 [𝘙𝘦𝘮𝘢𝘴𝘵𝘦𝘳𝘦𝘥] (𝘢𝘭𝘣𝘶𝘮)
𝘕𝘪𝘨𝘩𝘵𝘸𝘪𝘴𝘩 - 𝘋𝘢𝘳𝘬 𝘗𝘢𝘴𝘴𝘪𝘰𝘯 𝘗𝘭𝘢𝘺 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘦𝘩𝘦𝘮𝘰𝘵𝘩 - 𝘖𝘱𝘷𝘴 𝘊𝘰𝘯𝘵𝘳𝘢 𝘕𝘢𝘵𝘷𝘳𝘢𝘮 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘦𝘩𝘦𝘮𝘰𝘵𝘩 - 𝘐 𝘓𝘰𝘷𝘦𝘥 𝘠𝘰𝘶 𝘈𝘵 𝘠𝘰𝘶𝘳 𝘋𝘢𝘳𝘬𝘦𝘴𝘵 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘦𝘩𝘦𝘮𝘰𝘵𝘩 – 𝘌𝘷𝘢𝘯𝘨𝘦𝘭𝘪𝘰𝘯 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘦𝘩𝘦𝘮𝘰𝘵𝘩 - 𝘛𝘩𝘦 𝘈𝘱𝘰𝘴𝘵𝘢𝘴𝘺 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘦𝘩𝘦𝘮𝘰𝘵𝘩 – 𝘋𝘦𝘮𝘪𝘨𝘰𝘥 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘦𝘩𝘦𝘮𝘰𝘵𝘩 - 𝘡𝘰𝘴 𝘒𝘪𝘢 𝘊𝘶𝘭𝘵𝘶𝘴 (𝘢𝘭𝘣𝘶𝘮)
𝘉𝘦𝘩𝘦𝘮𝘰𝘵𝘩 - 𝘛𝘩𝘦 𝘚𝘢𝘵𝘢𝘯𝘪𝘴𝘵 (𝘢𝘭𝘣𝘶𝘮)
𝘔𝘦𝘵𝘢𝘭𝘭𝘪𝘤𝘢 - ...𝘈𝘯𝘥 𝘑𝘶𝘴𝘵𝘪𝘤𝘦 𝘧𝘰𝘳 𝘈𝘭𝘭 (𝘢𝘭𝘣𝘶𝘮)
𝘔𝘦𝘵𝘢𝘭𝘭𝘪𝘤𝘢 - 𝘔𝘦𝘵𝘢𝘭𝘭𝘪𝘤𝘢 (𝘢𝘭𝘣𝘶𝘮)
𝘚𝘦𝘱𝘵𝘪𝘤𝘧𝘭𝘦𝘴𝘩 – 𝘛𝘪𝘵𝘢𝘯
𝘚𝘦𝘱𝘵𝘪𝘤𝘧𝘭𝘦𝘴𝘩 - 𝘊𝘰𝘥𝘦𝘹 𝘖𝘮𝘦𝘨𝘢

𝗡𝗢𝗧𝗘: 𝘐 𝘵𝘦𝘴𝘵 𝘦𝘷𝘦𝘳𝘺𝘵𝘩𝘪𝘯𝘨 𝘪𝘯 𝘣𝘰𝘯𝘦-𝘴𝘵𝘰𝘤𝘬 𝘤𝘰𝘯𝘥𝘪𝘵𝘪𝘰𝘯. 𝘐 𝘈𝘓𝘞𝘈𝘠𝘚 𝘶𝘴𝘦 𝘸𝘩𝘢𝘵 𝘪𝘴 𝘪𝘯𝘤𝘭𝘶𝘥𝘦𝘥 𝘪𝘯 𝘵𝘩𝘦 𝘱𝘢𝘤𝘬𝘢𝘨𝘦 𝘵𝘰 𝘢𝘷𝘰𝘪𝘥 𝘢𝘯𝘺 𝘪𝘯𝘢𝘤𝘤𝘶𝘳𝘢𝘤𝘪𝘦𝘴 𝘰𝘯 𝘩𝘰𝘸 𝘐 𝘳𝘦𝘷𝘪𝘦𝘸 𝘵𝘩𝘦 𝘪𝘯𝘯𝘢𝘵𝘦 𝘴𝘰𝘶𝘯𝘥 𝘰𝘶𝘵𝘱𝘶𝘵 𝘰𝘧 𝘢𝘯𝘺 𝘨𝘦𝘢𝘳 𝘵𝘩𝘢𝘵 𝘐 𝘵𝘦𝘴𝘵.

➡️ Signature
I will be honest and upfront in saying that I am in no means an expert in reviewing dongles. I am more adept in my homecourt of reviewing IEMs and other gear that output the sound directly to my ears rather than the one that processes it. However, I can definitely tell that the Questyle M15 is doing wonders and miracles with whatever is put inside of it. Every aspect of the audible frequency is improved and polished to absolute perfection. As the title of this review indicates, the M15 feels like a deux ex machina in stories and movies: an item/event that saves and defeats every plot hole or antagonist present in just a blink of an eye. Both of its gain modes properly drive all the gears that I have, which can be a testament that it can power anything that you have, as long as it’s not one of those higher priced/vintage planar/EST headphones that has ridiculous resistance values. That’s how good this dongle is when put to every test, and it does it without breaking any sweat.

If I were to tell you about its general tonality, it can be classified as a very neutral experience, with some bias to the brighter and more analytical side of the auditory experience. The bass is excellently reproduced without any unnecessary tweaks that will make the sound artificially enhanced. The midrange is clearly represented without any hitches and weird peaks. It enhanced (without coloration) how instruments and vocals are layered, which is actually the first thing that I noticed when I plugged into this beast upon my unboxing. The treble is where things get slightly different: it makes IEMs/headphones a bit brighter and more technical when used. Every gear that I plugged into it gained an additional level of technical ability and brightness that I appreciated, most especially for warmer sounding IEMs. The only nitpick that I can pick out from using the M15 extensively is its tendency to make the soundstage slightly narrower, resulting in a more intimate listen. This isn’t easily noticeable though, as I have noticed this in my more critical listening sessions with the music that I know by heart.

Overall, the Questyle M15 is truly a monument in dongles, even in my debut experience of it. It’s just too good to be true, especially for people who are into this segment of the hobby. Even for me as a beginner, this is truly a great experience and a more-than-worthy start into the rabbit hole that is the #donglemadness.


𝙊𝙫𝙚𝙧𝙖𝙡𝙡 𝙑𝙚𝙧𝙙𝙞𝙘𝙩:
𝙋𝙖𝙘𝙠𝙖𝙜𝙞𝙣𝙜 💨💨💨💨🦖
𝘽𝙪𝙞𝙡𝙙 𝙌𝙪𝙖𝙡𝙞𝙩𝙮 💨💨💨💨💨🦖
𝙐𝙄 (𝙐𝙨𝙚𝙧 𝙄𝙣𝙩𝙚𝙧𝙛𝙖𝙘𝙚) 𝙖𝙣𝙙 𝙀𝙖𝙨𝙚 𝙤𝙛 𝙐𝙨𝙚 💨💨💨🦖
𝙎𝙤𝙪𝙣𝙙 💨💨💨💨💨🦖


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@o0genesis0o Thanks for the compliments mate! Goji says hi to you. :D
Love the way the dac looks!

The transparent cover looks good, might be a hassle to daily it. As might break it.
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@tubbymuc That glass is quite strong, deceptively strong actually. Especially when paired with the leather case, we haven't heard any reports of anyone breaking it yet 😉
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Headphones and Coffee

Previously known as Wretched Stare
Just amazing
Pros: clarity from one end to the other, great extension and low noise on most instances
Cons: some slight beginning noise with certain cellphones, this does dissipate.

This dongle comes with two cables one is USB-C to C and the other is USB-C to A, the small metal dongle has a clear window to see the internals and lights. the LED are bright, but I didn't find that bothersome. It has both single ended 3.5mm and Balanced 4.4mm for versatility. The M15 also has manual gain adjustment on the side via a sliding switch, LED indicators and as this is written a free case with purchase.

The M15 has very low ground noise, with noise floor of -130dB and its ES9281AC DAC chip is capable of decoding DSD256 native and PCM 32BIT/384kHz as well as an 8X MQA, and very good numbers when it comes to driving power with 22.6mW max on the 4.4mm output and just under 12mW for the 3.5mm output.

Sound impressions:
The M15 is without any doubt one of the best I personally have used. It maintains a neutral presentation with superb clarity and detail retrieval.
The Questyle M15, has both excellent dynamics and superb resolution making it great for critical and fun listening.
Bass, Mids, and Treble present with a linear extension with excellent technicalities.
The soundstage is open, accurate with separation and details.

I used a large variety of in-ear and headphones with this Dongle and it handled them all perfectly.
Fostex T50RP, the HiFiman HE-X4, the Moondrop Blessing2, Kato, and Aria, the Grado SR80x and the Philips X2HR to name a few.

Thanks for the review! Love the look of the dac.


100+ Head-Fier
Transparent indeed
Pros: + Premium materials
+ Great design
+ Removable USB-C cable
+ Balanced output with 4.4 mm jack
+ Neutral and transparent
Cons: - Pricey
Questyle M15 review.jpg

Small, portable DACs with an integrated headphone amplifier are more and more common, with an ever-increasing variety of inputs and outputs. The Questyle M15 keeps things simple while offering some flexibility with a 4.4 mm balanced output as well as a traditional 3.5 mm jack. What really sets this device apart is the design, which is quite unique, but we shouldn’t judge a book from its cover as there’s much more to it than just nice design.

Disclaimer: I received a free unit directly from the people at Questyle, whom I thank. The M15 retails for $249. Buy from Questyle

I originally posted this Questyle M15 review on my blog, Soundphile Review.

Rating: 9/10​

Packaging & Accessories​


The Questyle M15 comes in a simple yet elegant cardboard box which contains the device itself along with two cables: USB-C to USB-C and USB-C to USB-A. The company kindly sent me an additional USB-C to Lightning cable in a drawstring pouch, which you can buy as an add-on for an additional $20.

Design & Build​

The Questyle M15 has a transparent window taht shows the components

The Questyle M15’s design is surely quite striking. The presence of a transparent window that shows the circuit board with all the components is definitely unusual and shows quite some confidence on the part of Questyle, given how it displays the circuit layout – something that could potentially expose it to criticism from those who are more demanding in this regard. Still, it’s a sight to behold and I applaud this choice as it really sets the M15 apart from the competition. The funny thing about the transparent window is that it allows you to see how Questyle really optimised this device to be as small as possible and there’s no wasted space inside it.


A more practical consideration about the transparent window is that Questyle took advantage of it to show two LEDs on the board: the on the left hand side indicates gain and is either green (low gain) or red (high gain), while the one on the right hand side lights up to show the resolution of audio being reproduced with green (48 kHz or less), red (more than 48 kHz) and magenta (MQA).


The Questyle M15 has a flawless assembly, as far as I can see. The main part of the chassis, made of aluminium, fuses perfectly with the glass of the transparent window. The top hosts a USB-C port, while the left hand side hosts the gain selector and the bottom hosts the two audio ports, one 3.5 mm and the other 4.4 mm.

Features & Specs​


When I first tried out the Questyle M15 it took me a while to understand what was wrong, as the device wouldn’t show up in the available audio devices. Not only that: the system logs (I use Linux) showed that the device wasn’t even being detected as plugged in. It wouldn’t work even with my Android devices. I then realised that the M15 requires headphones to be plugged in in order to show up as an available audio device independently of your operating system, so keep that in mind!

Speaking of operating system support, it is supported by basically every operating system out there and works great with the Steam Deck, too.

Questyle M15

InputUSB (up to 32 bit / 384 kHz PCM, DSD256, MQA)
Suitable headphones impedanceN/A
Output impedance0.4 Ω (single-ended)
0.8 Ω (balanced)
Maximum output power11.97 mW (300 Ω, single-ended)
22.6 mW (300 Ω, balanced)
Frequency response20 – 20,000 Hz (± 0.1 dB)
THD+N (@1 kHz)0.0003%

The core of the the Questyle M15 is the ESS Sabre ES9281AC DAC, the same as the older M12. The device uses the company’s own Current Mode Amplification circuits, developed in-house to deliver lots of power while maintaining low output impedance and distortion – as evidenced by the data above. It should be noted that the distortion is incredibly low: at 0.0003%, it is even better than on some desktop devices, which is quite the achievement.

In terms of compatible formats, the M15 is able to play everything but the highest-resolution content, with PCM going as far as 32 bit / 384 kHz and DSD up to DSD256. It is also an MQA-compatible device that effects the final unfold.



I have tested the Questyle M15 with various headphones, including the Sennheiser HD 6XX, the HiFiMAN Edition XS, the Moondrop Stellaris and the RØDE NTH-100.

The Questyle M15 is notable because it delivers a completely black background – there is no hiss or hum whatsoever to be found, even when using a not-exactly-clean USB port (in terms of power, that is).

It has enough power to drive even demanding headphones with good authority; only the ones with very high impedance or extreme current requirements (like some planars) are not driven to their best. In terms of tonality, I find the M15 to be perfectly neutral, with no alterations made to the sound; it sounds really clean and clear, with great representation of the transients that sound fast and well-controlled. Decay is quite short, too, adding to this sensation of speed. Fast headphones like the NTH-100 delivery great transients with the M15 and sound even more engaging. A by-product of this is that there’s also a whole lot of details to be found.

There’s no significant difference in tonality when switching from the single-ended output to the balanced one; the difference is mostly in power output, which means that you should use the balanced output with higher-impedance or more power-hungry headphones (e.g. the Sennheiser HD 6XX) as it’s better able to drive them.

Final Thoughts​

At $249, the Questyle M15 is certainly not cheap. It has, however, everything you might ever need from a portable DAC – and even from a desktop DAC, to tell the truth – in terms of power output and format support. What’s most notable about the M15 is that it offers a completely black background, with no hiss whatsoever even with noisy source devices. This helps it deliver a great amount of detail. It drives even demanding headphones with authority and with sufficient power to make them loud and clear. The overall impression is that of great cleanliness, both in sound and design. This cleanliness has a price, but overall I feel like it is worth the expense, especially considering this is one of the few portable units that offer 4.4 mm balanced output.
Every where I turn, I see praise of M15 :beyersmile: So tempting


100+ Head-Fier
QUESTYLE M15: The Exemplary Authoritative Miniature Device
Pros: ● A sturdy device with metal casing chassis made of high quality aluminium alloy.
● That window glass panel which you can see the inner workings of its circuitry which is quite fresh and aesthetically eye-pleasing.
● Removable Type-C cable connector.
● Manual gain toggle switch.
● A versatile device supports and compatibility on either software applications level or hardware devices.(Operating Systems and media devices such as PCs, Smartphones, Tablets and Laptops)
● Impressive driving power output for such a tiny device.
● Tremendously uncoloured, unsullied neutral tonality.
● Up to par technical performance.
● High quality 4.4mm TRRS made by Pentaconn.
● 8x unfolding MQA support for Tidal streaming (For MQA listeners)
Cons: ▽ Absence of hardware volume key buttons.
▽ Yearning for at least a tad wider soundstage. (it's just my slight quibbling nature in regards of my concern but I can live with it)

Your big opportunity may be right where you are now.”

~Napoleon Hill, Author of Think and Grow Rich~

This quote really struck me so much when I received an opportunity to do a product review for an audio company in which I really thought that approaching them is next to impossible. I give my utmost gratitude to my audio mate who really believes in my capability as a decent audio reviewer. He is the one who's facilitating the contact between me and this audio company.


This audio company that I mentioned is Questyle (as it was already mentioned in the title above). As we all know that the brand Questyle especially to the veteran audio enthusiasts that it is a boutique audio company which has a cult following among the audio community. The brand Questyle embodies excellence in product quality and the delivery of the best possible sound quality that an ardent audiophile can derive upon.



Questyle is a Chinese premium boutique audio company whose product range mostly offers desktop amplifiers and other mobile audio solutions such as USB DAC dongles and digital audio player. It was founded in 2012 in Shenzhen by some visionary individual who wants to deliver the best audio experience with proprietary patented technologies such as CMA (Current Mode Amplification) and a 5Ghz wireless lossless audio system in a mobile and desktop-grade in a very compact form.


I'm familiar with Questyle since 2018 as their DAP, The QPR1 was a stuff of legend among the audiophiles in the audio community scene. Some even claimed that they finally found their "Holy Grail" which really even piques my interest about them even further. That's why when Questyle contacted me if I could do a review on their product, I eagerly accepted their offer without hesitation.


This is Questyle M15, It is their latest flagship headphone amp dongle which has a removable type-C connector with two types for termination jack of different power output. It is made of CNC milled aluminium alloy and has a size dimensions of 16.8mm x 27.2mm x 12mm and it is of a rectangular shape just like most typical USB DAC dongles of the same form factor. At the top of the panel, it has clear tempered glass where you can see the internals of the M15 which is quite fascinating and eye-pleasing where you can see the circuit board with its internal components like DACs, microchips, headphone jack casing, USB type-C jack casemate and their patented CMA with its transistors which I will explain later. At the both ends of this device, this is where the different types of ports situated on both opposing side, the USB type-C port on the other side and two types of termination jack, one is a 3.5mm TRS and the other one is a 4.4mm which was manufactured by Pentaconn, a Japanese brand that makes high quality audio components to other midrange and high end Hi-Fi brands like Sennheiser and Sony. At the one side of the parallel part of Questyle M15, there lies a toggle switch for adjusting the gain output manually where you can check the colour- coded status in a glass panel via its light indicator.






Furthermore for decoding sampling bitrate, there is also a dedicated LED light which is also placed at the opposite side with the gain light indicator. Questyle M15 can support PCM lossless format like FLAC, WAV and ALAC up to 32-bit/ 384KHz and DSD format up to DSD256(native). MQA decoding via streaming services like Tidal is also supported and can unfold up to 8x via hardware decoder processing renderer of its DAC.

DATA GREEN LED LIGHT - 16-32 bit, 44.1 KHz - 48 KHz.

DATA RED LED LIGHT - 16-32 bit bit, 88.2 KHz - 384 KHz / DSD 64, 128 and 256.

DATA MAGENTA LED LIGHT - MQA decoding and unfolding (works only in Tidal)


Other component parts of the Questyle M15 are the DAC, Amplifier and a power management module which I will divide it into parts.

ES9281AC is Questyle M15's internal DAC chip. It is ESS' latest flagship DAC which is mainly used for USB DAC and other mobile applications to achieve a processing and decoding execution similar to some desktop grade DACs. It also has a built-in high performance SABRE amp to achieve up to 2 Vrms output. There is also a jack detector on it that serves as "impedance sensing" to regulate a power output to load with proper resistance value to avoid unwanted erroneous reading due to external sources such as moisture and dirt.

CMA (Current Mode Amplification) is Questyle's proprietary patented technology crown jewel. It is a System-in-Package module which has multiple "audio amplification engines" with unified parts of circuits, chips and transistors in a single enclosure of a package to deliver an accurate, excellent detail retrieval and ample dynamics for a high quality sound reproduction either from a studio or recorded live performances. With its transistors and advanced circuitry to regulate voltage output and amplification, it manages to achieve a performance peak similar to a Class A amplifier (you read it right, an almost Class A amplification performance). There are two CMA modules that are implemented in the M15 dongle. You can check more infos about the CMA technology HERE for more technical description.

For its power supply module, It uses an analogue IC voltage regulator from Torex Semiconductor which is a Japanese firm that has years of experience in IC manufacturing and with extensive R&D to provide a better power efficiency and regulates well the temperature inside of the Questyle M15 to avoid overheating.



Questyle M15 packaging is quite simple when it comes to inclusions but still looks premium and elegant in presentation on how its contents inside are properly stacked in order.

Here are the included accessories inside of the Questyle M15's packaging box:

■ Questyle M15 USB dongle.

■ Short USB Type-A to USB Type-C cable.

■ Short USB Type-C to USB Type-C OTG cable.

■ Basic instruction manual.

■ Warranty card.


Bonus: Questyle also included an M15  Leather Case in green colour.


Like all USB DAC/Amp dongles, M15 is also a plug-and-play device with its handshake protocol to bypass any devices' stock audio resampling system by using a specific apps (for Android OS), streaming apps setting options (Tidal, Apple Music and Amazon Music) and Desktop OS settings (Mac OS, Windows and Linux). With a plethora of supporting devices like Android smartphones, Laptops, Personal Computers, Tablets (Android and iOS) and DAPs, Questyle M15 is indeed a very versatile tool for a mobile hi-fi tool.


If you are an iPhone user, you need a Lightning to Type-C cable which can be purchased from Questyle's official site.

Here are some information regarding the prerequisites on recommended versions of major operating systems and required apps for supporting playback for M15 in Android.

Android OS - you need at least a 5.0 version up to the latest one. The music apps that support Questyle M15 dongle are UAPP (USB Audio Player PRO), Hiby Music Player, Neutron App and Onkyo HF Player.

Windows OS - at least Windows 10 version 8.13 with no additional driver installation.

Apple MacOS - works mostly in all versions without any additional driver installation requirement in the system.

Linux OS - like MacOS, it works pretty well in all distros like Ubuntu, Debian and Linux Mint without any necessary driver installation requirements.

iOS/iPadOS - latest OS version that supports Apple Music app in lossless mode.

Regarding its power output delivery, Questyle M15 currently has the strongest power output in my current collection and some USB DAC/Amp dongles that I've tested in the past. Planars IEMs can be driven properly without breaking a sweat with impressive results. So harder-to-drive cans and some power demanding IEMs will be amplified properly. Even on some super sensitives, low impedance finicky IEMs, there is no hissing nor scratching sound present within its sonic background.


Here are more technical specification in power output rating on both audio jacks (Datas are provided by Questyle)

● 3.5mm TRS/SE= 300 ohms, Po= 11.97mW

VDF=1.895 Vrms, THD+N= 0.0045%

● 4.4mm TRRS/Balanced= 300 Ohms, Po= 22.60 mW

VDF= 2.624 Vrms, THD+N= 0.00057%

Due to the absence of hardware volume key buttons on M15. Adjusting its volume level will be done via volume key buttons or knobs of devices sources. Android music apps that supports USB DAC dongle has better volume steps with gradual incremental gain while adjusting the volume amount based on your preferred listening level.


Another reminder that Questyle M15 doesn't have a built-in battery and it acts like a parasitical implement with its host device's core power source to syphons off some amount of power to amplify the head/earphones. Due to the Torex power management system tech, Questyle M15 power extraction on its device host is well-regulated and its draining power is somewhat minimal with efficiency. So it is advisable to have a mobile device that at least has a high capacity battery for a longer usage to act as host for this implement.



As for tonality aspect, Questyle M15 has a balanced-neutral tuning with very clean, flawless, organic, sufficiently crisp with high degree of resolving yield. This is one of the most uncoloured sounding devices that I've encountered to a greater degree.



When it comes to bass quality, it is very clean, articulate and very responsive with adequate texture in both parts of the bass region.

Sub bass has excellent depth reach as I discerningly felt those rumbling sound. Listening on sub bass focus tracks from some genres like Hip-hop, RnB and Synth-pop has a very detailed reverberation produced by low tuned bass guitar, synthesizers and some electric drums.

Mid bass has an ample texture to give a body on these specific instruments like bass trumpets, bass guitars and bass drum kicks. Bass trumpets has this realistic tone as sound very intense, warm and full sounding just Ive listen to orchestras and military parades, bass guitar has a very topping quality that its growls have these crunchy dark, heavy and very resonant and even slapping, fretless and other type on picking on every strand is even well-detailed. And the bass kicks are very authoritative that exudes being thunderous and pounding one as the bass kick drum sounds like that as realistic as possible. (I usually attend on some underground musical gigs from Metal to Skas)

Bass-Baritone vocals have even garnered my attention on how it is presented in a guttural and strong manner. This bass quality should be presented in a very organic way, not too boomy nor too lean sounding.


Unequivocally, this is a very impressive and awe-inspiring midrange quality. Pristine, neutral and translucent that I even sense those layering elements of instruments and vocals. (I'll explain later in the layering aspect on technicalities part of this review).

Male vocals has an ample texture that gives a definition of being cohesive to all vocal types and ranges from a guttural bass voice to stately tenor vocals with its brassy and dazzling nature (love to hear those Three Tenors vocals especially Pavarotti). As for female vocals it has this sense of being organic, clean, very detailed, rangy and energetic. I'm a midcentric type of listener so I want my female vocals to be articulate, delineated and dynamically vivid. To describe the qualities of female vocals, I can enumerate in many possible descriptions. angelic, euphonic, luscious, well-modulated and sensuous that it really pleases my hearing senses in a very captivating and pleasant manner. All these descriptive characteristics exhibited in all female vocal ranges from a soulfully and sombre contralto to a vibrant and vigorous sopranos.

All types instruments ranging from percussives to strings have very natural and life-like sounding in a very engaging not to sound exaggerated and inaccurate tone that most coloured sounding usually exhibits as M15 maintain to sound uncoloured and equitable as possible. On percussive side, tom drums have this hard and majestic sound every hit by a drumstick, snare drums sound very precise, sharp and penetrating that its rhythmic attack is well-appreciated with accuracy. While timpani has this dull,dry and velvety sound depending on how it will be executed in different note ranges. As for strings instruments, it is so detailed that I clearly hear every pluck in each string of a guitar (Tears in Heaven live by Eric Clapton) and surprisingly, if you are aware the different tonal attributes of a guitar (acoustic) and very familiar with its choice of material usually types of wood that affects the guitar's overall tonality, you will notice the different tuning of it either it is warm sounding, balanced, dark, meaty or crisp. Violins have these different sound characteristics like lively, brilliant, rough or austere as it depends on the quality of construction and tuning of it. Brass and woodwinds are depicted in a natural and realistic manner that trumpets has that metallic and brilliant sounding, Horns has this muffled and velvety sound, Flute and fife has this bright, whistling with a sense of airiness and lastly, the sound of clarinet has these characteristic of lustrous and lively sounding.

It's too long to elaborate on how the midrange quality of Questyle M15 is beautifully well-rendered, and that it is very accurate, has an excellent detail restoration with greater degree of resolving without some colouration.


As a neutral sounding DAC/Amp, Questyle M15 exceeded my expectation of the quality of treble. It is very natural and inoffensive, neither too smooth nor aggressive in presentation. I contentiously believe that this is the truest representation of treble quality. Exceptionally detailed, with just a sufficient amount of shimmer not too make it more brighter and very airy with lots of harmonics.

Cymbals' sounds are precisely depicted in an instinctive manner as their sounds are very metallic, glistening, brilliant and sizzling. Hi-hats has this raw sound that it portrays its innate sound to have this shortened sizzle and buzzing characteristic.

Of all these impressive feats of Questyle M15 on how the treble quality was tuned. It managed to balance out and even improved those inherent character weaknesses of both aggressive and dull, dark tuned treble.


As highly resolving DAC/Amp mobile Hi-Fi dongle with the highest degree of superb technical performances, Questyle M15 is a highly capable that it has a good gap and spacing of all the elements inside of a track with a very orderly placement of every distinction of dynamic and frequency layering with in a clear, pitch-black sonic canvas. Imaging is very perfectly executed as I clearly locate the placements of vocal(s) and instrument with no sense of haziness and obstruction in a 3D-like sense of immersion.

Regarding its soundstage proportion, its width dimension is fairly more of an above average, with excellent height and a well-defined placement between front and rear as it does have less reverberation with just sufficient amount of projecting energetic streak to have that sense of immersion and envelopment. Despite of that above average soundstage, it does have a spacious head stage within its perceived spatial field.

As for tonal colour, Questyle M15 is certainly neutral with almost to none amount of colouration. And with its exceptional resolving on detail retrieval on both micro-details and macro-dynamics and superb clarity, Questyle M15 is a fine piece for audio reviewers, audio professionals and audiophiles alike that a terribly produced and defectively mixed track will be thoroughly dissected to expose its flaws from sonic artefacts to audio clippings.


AudioQuest Dragonfly Cobalt (£258/US$300)

● Currently, the most expensive USB DAC Dongle that I have tested until now. Cobalt has a smaller form factor compared to Questyle M15 and it has hardware volume control button which is a more logical and more convenient implementation. But there are some caveats on Cobalt, it has only one single jack output and it is a 3.5mm SE and it is certainly designed for PC or laptop usage as it has a USB-A as its main connector which if you are a smartphone user, you really need some adapters which add more complexity and hassle.

● Regarding its tonality, Cobalt has a tad of colouration with its overall frequency range spectrum compared to M15 which is more neutral and organic sounding but Cobalt has still a clean and clear delivery. Different tuning for different folks, which you will choose? A warmer and musical Cobalt or an unadulterated and a bit clinical tonality of M15?

● On paper, Cobalt has limited playback resolution as it was only capped up to 24-bit/96KHz but it has Tidal MQA playback support. Both Cobalt and M15 has ESS DAC on their internals but different model, Cobalt uses a popular and reputable ES9308Q2M on its system and microcontroller power management chip from Microchip Technology Incorporated which is also a reputable company (they even have manufacturing plant here in my country). Cobalt has a bit wider soundstage but M15 has better imaging, separation, layering and resolution capability. Cobalt's power output is a bit underwhelming compare to M15.

LOTOO PAW S1 (£146/US$169)

● I've tested this one a few years ago from a friend, Paw S1 has also a solid built device like M15 and it's also made of metal alloy and if my memory serves right it's a bit more weighty compared to M15. It also noted that it has a small LED display to check the volume level and EQ mode…Yes, it has a volume control button and EQ system. PAW S1 uses a DAC chip from highly regarded audio solution maker, Asahi Kasei with its AKM4377 model.

● As for tonality, S1 is more coloured sounding due to added warmth but it has a velvety and luscious midrange in which AKM DAC is known for with its Velvet Sound tech. I can safely say that Lotoo PAW S1 is more for fun sounding and pleasurable musical tuning rather than for critical listening.

● It has lesser power output compared to M15 in both 3.5mm and 4.4mm but good enough for IEMs and earbuds. Most technical aspects are a bit inferior on S1 but at least it has a wider soundstage and even more spacious headspace.

As I end my review and put a verdict on this one, All I can say is that Questyle M15 is an absolutely outstanding mobile device in another higher-tier category. It has tremendous sonic quality performance and top-notch technical performance which only rivals some desktop-grade DAC/Amps in midrange and even some top-of-the-line Hi-Fi range ones in my humble opinion. (Still desktop DAC/Amps and Preamps has many functionalities and has a proper amplification within its circuitry to handle high powered and demanding speakers and headphones).

And now regarding the tale that I've mentioned a while ago about the "Holy Grail" thing on a Questyle DAP. Looks like that I finally have an enlightenment on how great Questyle products are, and my scepticism on that man's claim seems to be eroded and shattered and I became a true believer in Questyle (I'm an irreligious bloke though). Once again, Questyle M15 delivers a truly marvellous neutral tonality and a life-like timbre with a highly-resolving and terrific technical performance that truly Questyle will be proud of their prowess and elan in audio engineering.

Questyle M15 is currently available to all online stores in popular e-commerce platforms. If you are really interested in purchasing this device, you can order them directly from Questyle in the link below this description.



Some Tracks Tested: ( * = 16-bit FLAC, ** = 24-bit FLAC, *'* = MQA, '*' = DSD, *'= .WAV)

Alison Krauss -When You Say Nothing At All *
Jade Wiedlin - Blue Kiss**
Led Zeppelin - When The Levee Breaks **
Mountain - Mississippi Queen *
Queen - Killer Queen **
Guns N' Roses - Patience *'*
Eric Clapton - Tears in Heaven '*'
Sergio Mendes- Never Gonna Let You Go '*'
Pearl Jam - Daughter **
Roselia - Hidamari Rhodonite *
Assassin - Fight (To Stop The Tyranny)*
Celtic Frost- Visual Aggression *
New Order - Blue Monday *
The Corrs- What Can I do (unplugged version) *
Jimi Hendrix Experience - Voodoo Child *
The Madness- Buggy Trousers *
Metallica - Motorbreath **
Mariah Carey- Always Be My Baby *
Destiny's Child - Say My Name *
Malice Mizer- Au Revoir *
Mozart - Lacrimosa *
New York Philharmonic Orchestra - Dvorak- Symphony 9 " From the New World." *
Eva Cassidy - Fields of Gold (Sting cover)*
Michael Jackson - Give In To Me *
Exciter - Violence and Force *
Diana Krall - Stop This World **
Debbie Gibson - Foolish Beat *'*
The Sisters of Mercy – Lucretia My Reflection**
Suzanne Vega – Luka **
Lauren Christy – Steep *

I am not affiliated to QUESTYLE nor receive monetary incentives and financial gains as they provide me a review unit for an exchange of factual and sincere feedback from yours truly.

Once again, I would like to thank to Mr. Zach of QUESTYLE for providing this review unit. I truly appreciate their generosity towards me and other reviewers.

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Great review, mate! It seems that every where I look, I see praise for M15. When I reviewed the S9 Pro recently, I couldn’t give it more than 4/5 because the spectre of M15 is always on the horizon. It seems M15 is not as draining as S9 Pro :thinking:

Will try to grab one to review one day, after upgrading my top IEM (likely forever, because I keep buying cheaper new stuffs for review:beyersmile:)
@o0genesis0o thanks mate. I'm glad that you are enjoy reading my content.


Headphoneus Supremus
Questyle M15 - Proving Questyle is back
Pros: Sound quality, size, efficiency, power, staging/layering
Cons: Gain switch difficult to access when inside of the case, can be a good thing though for no pocket sound surprises.
Questyle M15 - This review is going to be a stream of thoughts and impressions. I hope you enjoy.

Today on my desk I've got the Questyle M15. The M15 at this point has a strong following and I've been determined to see if that following would stand up past the initial release hype. Questyle has promised a full CMA implementation in this tiny dongle with power consumption and running temps that are in check - we'll see if they have held up to that goal in this review.

Before receiving the device I did what any sane person would do - research and assume, right? On their website Questyle has marketed this as having incredibly low distortion, to the tune of 0.000X% and beyond. Inside is a capable ES9281Pro DAC chip that hands off the signal to their new current mode amplification SiP modules. I'll be honest I'm a bit in the middle on if I'm a fan of Sabre. I have heard DACs flat as a board with enough pierce in the treble to give me a headache before the first song is over. The Fifteen from Questyle is the first later revision Sabre chipset I've heard that has completely transformed my impressions of Sabre largely thanks to the CMA output stage.


Given this experience, I had high hopes for the M15. I was a bit worried when I read the power specs however. For some reason it is measured on their site at 300ohms. The M15 supposedly puts out 11.97mW on the 3.5mm output and 22.60mW on 4.4mm. Once I received the dongle in though I believe numbers are so incredibly conservative it isn't even funny. With my AKG K712 I am sitting at 23 OS volume in low gain with Foobar playing at -18dB attenuation. This is my upper threshold of what I can handle for routine listening. This dongle is an absolute powerhouse. Switching over to my modded HD650 I could only nudge Foobar to -16dB! This performance proved the M15 is more than capable of driving anything I own, either IEM or full size power hungry headphones.

When listening to the M15 and switching to IEMs one has to be careful. I dropped the volume to the floor when switching over to IEMs and creeped up from there. It seemed that from my phone the power was a touch more conservative (still plenty of it though) and my PC was capable of feeding it even more. So, this gives me confidence Questyle has power management in check on this little device.

Also very important to note is that the running temperatures on the M15 are crazy good. It barely gets warm to the touch, even attached to my desktop PC. The new CMA SiP modules are an engineering feat to have such power. Very akin to THX design however sans the sterility in sound, but more on that later. In my pocket the M15 was completely unnoticeable. Questyle was on a mission with this dongle I believe. Size, power, sound and efficiency. The size to me makes the lack of internal battery or wireless connectivity a non issue. The sound from the M15 blows every wireless device I've ever tried out of the water, enough to sate my old school belief of 'wired of always better' anyways.

My mobile testing consisted of my trusty OnePlus 7T and as a mobile platform the M15 exceeded my expectations. I had no dropouts, stuttering or sync issues. I also did not encounter any EMI noise - which given that one side is glass I suspected the M15 may have been impacted. No issues, though given it is a dongle I'd have rather had the choice to either have a removable metal plate over the glass or just not a glass side at all. It has taken a few good thwacks in my pocket though, so whatever they are using is rather robust. There is a nice leather case for it available through Questyle as well in several colors. It does allow for some nice visibility through the glass of the status lights within. These notify you of different rates and connectivity/power. Let's move on.

(The size of the M15 is incredible)


I figured I'd just use the M15 as a convenient portable for LAN events and on the go. Definitely for downtime at work. The M15 has proven to me that it can fulfill those roles, however it went a step further. It completely replaced my desktop setup for gaming. The M15 is accurate, incredibly so. When testing with Hunt: Showdown which features binaural audio I was greeted with a boundless soundstage with excellent layering. Bass was in check yet present and engaging. Treble was not so explosive that it was uncomfortable and the midrange is so smooth without losing detail. It is also very clear. Even better though, it was resolving beyond even some of my desktop gear. Decay is incredibly detailed and natural so the sound doesn't come off as either too warm nor too sterile. The negative feedback gear I've owned previously (think THX, Topping, etc) has a habit of squashing the sound and compressing the stage with a very 'wall of sound' effect in this game. This capability was very unexpected from the M15.

When it comes to music the M15 performed incredibly well here as well. I've got some state of the art desktop gear and for a dongle not to embarrass itself in the slightest is a huge testament to the engineering that went into it. With my setups each has a specific pairing it excels at. The Fifteen dominates with my AKG K712/HD660S with the BF2/J2 coming through with a different flavor for these headphones. LIM/Rag2 lights up my Sennheisers and my LS50 speakers. Mixed up, each of these systems looses their engaging synergy and in case of the AKG K712/LIM/Rag2 setup becomes harsh. With the M15 I experienced an enjoyable listen through everything I connected to it. Was it on the level of Schiit gear with an HD650? No.. Was it a lesser match like other pairings I've got? Not at all. Same can be said when arranged the other way. When listening to the M15 for extended periods I didn't outright miss my other desktop gear, which is the highest praise I've given any portable.

As far as putting a pin on the sound I'd call it detailed yet natural. The resolving capability from this DAC puts it well ahead of any competing gear in the same price range. A competing Schiit stack would have to be over the 1K mark and still doesn't perform as admirable with every headphone/IEM I've thrown at it. When a key pairing hits it can absolutely be better, but the M15 itself doesn't seem to care what you connect to it. Everything sounds great. The Bass performance from the M15 goes deep and is very engaging. It takes the HD650 as low as it will go and the AKG K712 even further with a strong but not overwhelming presence. It is also fleshed out. Male vocals are engaging with have weight and authority. Midrange is incredibly resolved and the treble has sparkle that doesn't overwhelm. There is no thin sound from this dongle, which cannot be said for much of the competition I've heard (here is to looking at you, FiiO...sorry)

There is one gripe I do have about this device though, and that is when connected to a PC that gets turned off I needed to unplug and replug the headphone cable to get the M15 to 'wake up' and be seen again. I'm assuming this could be altered in the firmware, I'm using Windows 11. It could also be a standby power setting on my system that is causing this and it isn't a huge deal. I don't think it was designed to be a desktop device at all yet it really is competing in that realm. With these new modules I really hope Questyle puts out a USB powered desktop Dac/Amp. There would absolutely be no competition in this segment if the performance exceeds the M15.

As far as portable comparisons I can comfortably say the M15 has outperformed everything I've heard and owned. It is more layered than the iDSD Gryphon - and somehow more usably powerful despite the Gryphon's specs. The Gryphon had some compression in the lower registers that put me off. Where the Gryphon exceeds the M15 is capability of features and compatibility. FiiO BTR series? Not even close when it comes to sound quality however it IS wireless. iDSD BL/Signature? Not neutral in any sense of the word but I would say the bass is more engaging, given it's added coloration. The Sig/BL soundstage has a three blob thing going on and it definitely lacks the M15's resolving capabilities. I struggle to point out a specific weakness with the M15 while it puts a performance in each metric that could be considered solidly very good.

I've not much else to add on the M15, aside from that the praise it has received since launch is absolutely warranted. Many of these have sold and the thread is active, yet I've not seen many used units for sale. I'm observant of these things as it sends up a possible flag of hype in my hunt for great audio. Anyways, thanks for sticking around for this long and I wish all my readers the best. Jam on!
White Hat Bob
White Hat Bob
I have the BTR7. I have compared the Earmen Collibri, which has the same ES9281Pro and ESS SABRE PRO chips as the M15, with the BTR7, which has the ES9219C and THXAAA-28 chips, and the Collibri definitely sounds better than the BTR7, so it's safe to assume the M15 will also likely sound better than the BTR7. The BTR7 has a nice implementation of a mini-screen, Bluetooth, nascent EQ, a connected app. etc, but the sound is meh, especially when using Bluetooth. The Collibri has none of that but has a great case (with a belt clip which the BTR7 case does not have), separate USB-C and Data ports (which help it sound so good), a 5-hour battery, and a button/case/balanced 4.4 mm pentaconn configuration with strong output that is great for walking/running. If I didn't already have the Collibri, I'd definitely take the M15 over the BTR7 even though I'm a FiiO fan (Love my FiiO M11 Plus ESS DAP).
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Thanks for this info White Hat! I'm not a huge fan of the THX sound on mobile devices I've tried. I think the Questyle amp circuit used here has a ton to offer. I hope you get to try the M15, it is priced really well for the performance.
Great review!!
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500+ Head-Fier
Questyle M15 Portable DAC/AMP Review: Robust Build, Solid Looks, Impressive Sound!!
Pros: Eye candy, the transparent front looks super good.
Impressive sound, fluent dynamics, transparent, clean signature.
Synergizes well with almost everything I tested it with.
No background hiss or noise issues with sensitive IEMs.
Cons: No physical volume keys, depends on the connected source for volume adjustment.
EMI Noise when source uses Mobile Network. No issues while using Wifi.
Hello Friends, Today, I am going to share my review of the king of the dongles, the @Questyle M15. Questyle Audio Engineering is a premium HiFi audio gear brand from China that specialize in designing Desktop and portable DAC/AMP solution. They cater to the premium consumer with their class-leading range of HiFi audio gears with famous models such as CMA Twelve, CMA Fifteen, QP2R, QPM, etc. Quite recently, Questyle entered the budget market with their range of Portable DAC/AMPs, mainly with the M12 and the M15. M12 is the budget model while the M15 is the flagship model that comes with ES9281AC premium Sabre DAC and Questyle’s patented CMA(Current Mode Amplification) SiP Modules with a total of four CMA Amp Engines. Well, I have spent the last few weeks with the M15 by my side(About 6-8 weeks), and now I feel I have spent enough time with the device to give my impressions on the same. Let’s begin with the unboxing part but a little disclaimer first.

A short Disclaimer:-

I received the M15 courtesy of Questyle, I just had to pay the custom duty that was charged in my country on the package. Be assured, all the impressions and opinions in this review are completely my own and are based on my own subjective understanding of the HiFi audio world. I would like to thank Questyle for giving me this opportunity!! You can check out the technical details and purchase it from the Hifigo link below(non-affiliated):-

You can also read my review on the Gizaudio website here.

Let’s Get Done With The Unboxing:-

M15 is a portable device and it comes in a compact box. It’s a plain black colored cardboard box that has a minimalistic design approach. You have the Questyle and M15 branding on the front and some basic information on the backside. The package opens in a sliding manner, where you pull out the internal box from the outer casing. Inside we have the M15 sitting firmly into a hard foam cutout layer. There’s a USB Type-C to Type-C connector cable and a Type-C to Standard USB Type-A connector cable right underneath our M15. Apart from this, we have a user guide booklet and a warranty card. That’s all about the main package. I also received a small box carrying the leather case of the M15. It is available to purchase separately.

Package contents:-

>M15 portable DAC/AMP.

>USB Type-C to Type-C cable.

>USB Type-C to Type-A cable.

>Warranty card.

>User guide.

>Leather case(To be purchased separately).

Design & Build:-

During my journey as an audio enthusiast I have had a small share of experience with some portable DAC/AMPs from different brands like iBasso(DC03), HiBy(FC5), xDuoo(Link 2 Bal), Shanling(UA3), etc, IMO M15 trumps them all with its outstanding build and form factor. Please don’t get me wrong, none of the ones I mentioned above have a bad form factor or bad build quality, they all look super good in their own place, but the M15, it looks spectacular, literally a candy to the eye. The device has a metallic chassis with a glass front. The entire front panel is made up of durable glass through which the entire internal arrangement is beautifully visible. You can see each and every single chip inside easily. M15 has two small Leds near the USB connector, one that indicated Data input(this glows green for standard signal and red for Hi-Res lossless signal quality/MQA signals), and the second is the gain LED that glows in green for the low-gain and Red for the high-gain mode.

In the Images M15 looks huge compared to the other DAC/AMPs, It’s a little bit bigger than the other similar devices in the market but not huge or bulky by any means. M15 houses two headphone output ports, one single-ended 3.5mm and another balanced 4.4mm. It feels super good to hold as Queasily has treated it with a rich matte finish. There’s a switch on the side that allows for gain change, but no physical keys for volume adjustment. Overall, Super impressed with the build and design of the M15.

IEMs & HPs I have tested with M15:-

During my usage period over the past few weeks, I have given a good amount of IEMs to the M15. I tested it with IEMs from every range, be it the entry-level CCA CRA or the flagship 64audio Tia Fourth. Questlye’s patented CMA technology makes the compact M15, a powerful device. It was able to drive my ZMF Auteur to about 80% of its capabilities. M15 synergized well with almost everything that I had given it, here are some short notes on my favorite pairings.

Sennheiser IE600+Questyle M15:-

Absolute bliss, the M15 and IE600 synergize so well together. M15 brings the true capabilities of IE600 out with its transparent and smooth sound presentation. This is my primary go-to setup for regular music listening on my iPad(Apple Music), and watching some Netflix, and YouTube.

64audio U12T and Tia Fourte+Questyle M15:-

Out of all the sources that I have currently, be it the Shanling M7, be it the Shanling UA3, or be it the Astell&Kern Kann Max, M15 has the best tonal balance with the 64audio IEMs. Please don’t get me wrong, obviously, dynamics were produced better on the M7 and the Kann Max, but tonally speaking, M15 doesn’t lack behind by any means. It allows the U12T and Tia Fourte to breathe properly and produce a legendary experience with every single track.

LETSHUOER D13+Questyle M15:-

Regular companions for my casual music and Youtube sessions on my iPad. With the M15, D13 shows its true, powerful bass response and still maintains good clarity in the other regions as well. Pretty good combo for all-time use.

Apart from these above-mentioned IEMs, I have also used M15 with BQEYZ Topaz, LETSHUOER S12, Campfire Audio Solaris OG, Softears RSV, and a few more sets. No complaints with any combinations, heck M15 turned out to be a perfect match for most of the IEMs I have tested it with.

Sound Performance:-

How do I expect my sources to sound? IMO they should synergize well with my IEMs(that the M15 does), they should have a transparent, clean sound that brings the true performance of my IEMs/HPs out. Well, to my pleasure, this is how the Questyle M15 actually sounds. This little baby here has got a transparent sound signature with low distortion and clean, noise-free background in the output signal. Even with sensitive sets like the U12t, Solaris, and LETSHUOER D13, the M15 maintains its clean presentation. I don’t find M15 to boost any of the frequencies unnecessarily or take the life out of any frequency region, rather it retrieves most details and dynamics from my music.

Tonally speaking, Questyle M15 gives a smooth, rich tone to its output. Dynamics like note-definition, staging, layering, and imaging, are reproduced beautifully with the M15. Let’s discuss a little about different frequency segments separately.

Lower-End/Bass Response:-

M15 presents a clean and precise lower end. It doesn’t overly exaggerate the bass response for any given set. For sets such as Letshuoer S12 and Sennheiser IE600 which have a powerful bass response, I find them to have a controlled presentation in the bass region with the M15. With the IE600, the bass response is very well-refined, mid-bass slams are nicely textured, and the sub-bass rumble is deep and thunderous. M15 allows items to go deep in the lower end and deliver quality extensions.


M15 greets the listeners with a lovely midrange. It’s spacious, airy, and has a clean texture. Vocals sound phenomenal, both the male and female vocals convey emotion with their well-textured clean presentation. M15 maintains a good balance between lower mids and upper-mids. You won’t notice vocals getting shouty even at louder volumes on vocal-focused tracks or instruments losing details in any given genre.


Questyle maintains its sweet response in the high-registers too. I don’t notice any of my IEMs going harsh or fatiguing even at loud volumes. There’s no noticeable sibilance or harshness with the m15 as a source, in fact, high notes of vocals and instruments are produced beautifully with good resolution and clarity. For any portable DAC/AMP, I would say Questyle M15 does a great job with its crisp resolution and sweet tone throughout the frequency band.


Of all the Portable DAC/AMPs that I have tried to date, the Questyle M15 seems to have the best dynamics so far. I won’t mind saying that it beats some mid-fi DAPs easily when it purely comes to dynamics like soundstage, imaging, layering, and separation. While I agree this also depends on how capable the IEMs are, but M15 brings life to almost every single set that I have given the M15 to.

A Few Things That Can Be Improved:-

Basically, sound wise the Questyle M15 fits perfectly for my requirements. It has a dynamic, lively sound and usually synergizes well with almost everything I have given this beautiful DAC/AMP. But there are a few things that could be improved with the M15.

Firstly, there are no physical volume control buttons. Basically, there’s no volume control through the DAC, one always has to adjust the volume through the connected source. While it is not a big deal, three to four times I forgot to adjust the volume on my source, and it was set at full for the USB output. So basically, my ears had a stroke for a short while lol.

Secondly, M15 introduces some noise when we use it with smartphones/tablets with cellular network streaming. I personally don’t use Cellular streaming as I am mostly near a WiFi connection, but some people faced this and we had a discussion on the Head-Fi forum for the same. There’s no such issue when using Wi-Fi, but with streaming on a cellular network, there’s Noise interference.

Apart from these two points, I can’t think of any other issue with the M15.

Short Comparison Against xDuoo Link2 Bal:-

Link2 Bal is a highly-capable DAC/AMP from xDuoo. It delivers a punchy sound performance that brings life to most of my transducers. It is very much comparable to the Questyle M15 in its presentation but I would say M15 takes the things up a notch when it comes to dynamics. M15 shows better staging with a tad bit better airiness on the stage. It feels more spacious to my ears. Bass feels tighter and more controlled on the M15, Link2 Bal isn’t very far, it’s just M15 has a better presentation in comparison. Midrange shows more air and clarity on the M15 and treble has a smoother response. Please don’t get any bad ideas for the Link2 Bal. It’s a pretty amazing DAC/AMP too, but the M15 is just a step ahead in every possible way.

Final Words:-

I am more of a Portable Player guy, but often I have given time to portable DAC/AMPs. Nothing so far had me hooked on them for my day-to-day usage. The Questyle with its impressive performance gets a special place in my heart. I absolutely adore the impressive sound performance of the M15, it sounds phenomenal throughout the frequency band. Not to mention, the transparent glass front panel adds 100 points to its great design and looks!! Well, that’s about the Questyle M15 from my end, I would like to thank Questyle for this opportunity!!


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Nice and detailed review
Love this M15!


New Head-Fier
Questlye M15 - The Alrounder
Pros: Natural Sounding
Excellent Upscale grading
Driving Power is huge
True MQA decoding
Compact Size/Light Weight
Fabolus looking
Gain Switch
Bang for buck
Cons: Glass Panel, Can be broken if not carefull
Absent of Volume Button
High Pitch on some songs
Dongle has now become a must have auxiliary product for anyone which helps a lot to get better output from even a phone. Sometimes it may not be possible to buy or carry an external big size amp/dac or dap when you are travelling
Dongle has made that easy. From the beginning of the release the m15 has attracted so many people that i also wished to check it out

Previously I have used dongles but those were not as pricey as this one. So I was a little bit worried about whether it would be able to give me performances according to its price . The price was about 250$. But later I got relaxed after experiencing the Questyle M15
There was another dongle m12 from the same company at half of it's (M15) price which was also a good dongle as far as I am oncerned.Yeah I cannot afford all the dongles but i always keeps updates from local friends and colleagues.


Android phone and pad: Android 5.0 and above
PC: Win10 1803 and above
Apple cellphone: iOS (You need to buy an OTG cable for Lightning to Type-C.)
Apple computer: mac OS

PCM: PCM: 32kHz – 384kHz (16/24/32Bit)
DSD: DSD64(1 Bit 2.8MHz) , DSD128(1 Bit 5.6MHz), DSD256(1 Bit 11.2MHz)

When playing audio, the data status indicator will illuminate one of the following colors:

Green: indicates the audio sample rate is 48kHz or less.
Red: indicates hi-res lossless playback.(Hi-res lossless refers to PCM 88.2kHz~384 kHz, or DSD64~DSD256.)
Magenta: indicates the M15 is performing the final unfold of an MQA Core stream.

3.5mm standard headphone jack x1
4.4mm balanced headphone jack x1

3.5mm:RL=300Ω,Po=11.97mW, Vout(Max)=1.895Vrms,THD+N=0.00045%
4.4mm:RL=300Ω,Po=22.60mW, Vout(Max)=2.624Vrms,THD+N=0.00057%

Frequency Response: ±0.1dB(20Hz-20kHz)
THD + N:0.0003%
DAC:ESS flagship USB DAC chip ES9281AC

DAC Capability
Low power consumption, no overheating
Long battery life, longer playback
Unparalleled ease of use
Plug-and-play, no drivers needed
Your HiFi, anytime, anywhere
Metal housing, transparent cover
Minimalist on the outside, stunning on the inside

The M15 contains two of Questyle’s patented CMA (Current Mode Amplification) SiP modules, for a total of four CMA amp engines. This quadruple drive amplification circuitry gives an outstandingly strong output that can drive almost any headphone. Questyle’s Current Mode Amplifiers are characterized by their small footprint, low voltage operation, and minimal power consumption. Current Mode amplification has a naturally low impedance, affording the M15 a bandwidth up to 1MHz, distortion as low as 0.0003%, and the ability to reproduce every detail hidden deep within any track.

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Unboxing Experience was quite interesting for me. Come in a premium small black box . It was wise of questyle to use a small and light weighted box because in my country tax is sometimes implemented on the size of the box.
I got an extra type C to Ios cable & Black Leather Case (worth of 25$). But the original package does not have the ios cable. Apple product users need
to buy that cable separately at 20$
Usually the following items comes in the box

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1 x Questyle M15 Ultra Portable USB DAC/Amplifier
1 x USB Type-C to USB Type-C Low Profile Cable
1 x USB Type-A to USB Type-C Low Profile Cable
1 x Print Material (Instruction Manual & Guarantee Card)

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Small , handy , Compact size . Very light weighted. One of the side of M15 was covered with a glass faceplate which tends to see the inside beautiful structure of the M15
It also represents the transparency of the questyle that truely used inside the dongle. There are 2 ports on the dongle.
One is 3.5mm Single Ended (with CTIA support for headphones featuring phone calls) and the other one is 4.4mm balanced TRRS port. One the corner of the m15 there is a button to adjust the gain with high and low.
I was disappointed that there is no volume rocker button. I mean it is not mandatory but it helps sometimes. One the bottom of the m15 there is type c port to bypass the sound

Sound Impressions:
I have Actually used the high gain mode all the time when using the m15 with iems.its seems High gain always gave better output with great resolution to me. When using in high gain mode I have to set the volume to 50% . Its could be easily understand that the output has great amping capacity as well

The device I used was Samsung galaxy note 8 and my laptop. As mentioned on the specification I do not need any driver to install to use M15
The provided type c cable was good but I tried other type c cables as well. Those work perfectly without any issue. I liked the dd hifi tc05 instead of the stock cable. But I must say the build quality and material of the ios cable (Which needs to buy separately at 20$) was much better than the stock type c cable

When i first plugged the m15 in my mobile and played a song from spotify I was feeling what is this, is that the small chilli with extreme hot. The details , the energy , the transparency , the separation (although provided by the IEM,but I got better using the m15 that couldn't be found with others dongles) was too much good
I am an iem guy so all of my testing unit was iem.

Questyle m15 is a kind of neutral sounding dongle, Sound is natural and crystal clear, Good clarity.
It was providing a non-colorized sound. very detailed and wide
While using it with IEMs in my room i didn't get any background noise with 50% Sound. It was like I was sitting in a quiet place.
It has really surprised me because I have never found my iems can detach me from the sound of the world. M15 got me recognized to my iems with their new identities.Because usually i didn't get this kind of good result
My Iems were Little dot cu red, Rose technics QT9 M2ks/QT 7 pro 2 , Tralucent 1+X plus 10th year Edition, tri audio meteor, Kinera skuld, Anew x1, Shanling
m15 was also providing me a holographic realization while listening to music and giving me synchronous rhythm.
There was not any hissing or noise while using it.


The way it was delivering sound from low to high without any compression was really superb
Bass was good as well.Punchy, Not boomy.Sound does not fatigue. For me, excess bass could cause a headache. so bass was in good amount from the m15
I have tried to play some only vocal songs to better understand the vocal.Both male and female were great on the m15. The residue voices while finishing a line and about to start the next line was easily audible.
For songs with music the Voices were forwarded then the other instruments and I could easily separate where the instruments were playing.There were remarkable spaces between the instruments with good texture.
The way m15 upscale the whole music to upper grade without any issue was not only good but excellent. Airy vibes were present there as well
But sometimes I was facing some issues with treble. It was providing high pitch on some songs which really hurt my ear.
The soundage reproduction was accurate and had good depth.

I have sometimes used the m15 for about 3/4 hour at a stretch. The battery drain of my Samsung galaxy note 8 was minimal. The heat generated on m15 was very much low. I have used the leather cover with it. But i have checked the dongle temperature by removing the cover also. Does not produce any excess heat
It got heated slightly


I would like to rate it 5/5 after examining it for a long period of time.As I keep news about the local audio market in my country I get to learn that people are going crazy behind it. This has become their first choice if the budget is not a problem to them.
Spending 250$ for it is worthy but i would like to get a better type c to type c cable at this price point. Also Iphone users have to pay an extra amount of money for the ios cable. That could be provided free like some other brands.
I am hoping that the M15 will be my daily driver from now on . Because the output it is providing according to size is really praiseable.
For many people it was a problem for them not having a volume rocker button but i didn't miss the volume button that much. Yes it was needed for me to increase the sound sometimes but i could increase from the phone

Highly Recommended. The Questyle M15 can be bought directly from Questyle, Hifigo or from local dealers. Questyle has many dealers around the world.
I don't think that driving power of this dongle is huge by the given specs.


New Head-Fier
Questyle M15 - the "Revealer"
Pros: reference -grade sound quality
Excellent price-performance ratio
Appealing design and looks. The glass-way alone is a killer look.
Bread and butter features
Ground-breaking tech namely the CMA SiP modules that they have in their full-pledged amps
Neutral sound signature with good dynamics and not sounding too clinical
Enough power to drive full-pledge headphones as other reviewers claimed
3.5mm and 4.4mm outputs compare to M12 which has only 3.5mm
Super low floor noise even on highly sensitive gears
Direct compatibility for IOS devices which not all dongles possess (optional type-c to lighting cable can be purchased from Questyle)
Physical gain switch (low and high gain)
Superb performance in terms of technicalities (more of this later on)
Cons: Quite large in size for on-the-go setup
No physical volume adjustment (subjective)
The price can be steep for starting audiophiles. But hey, nobody said this hobby is cheap. The price is exactly $249.
Sound stage could have been wider (nitpicking)
Poor shielding causes interference aka EMI noise emitted from cellular data
Hello and mabuhay from the Philippines! Here we are for another audio gear review! And this time, a new kind of gear. A dongle! This will be my first attempt to review a dongle. If you have been around the audio community, you must have heard of AndyEF who initiated the Dongle madness. And what I have here is a top-tier dongle and I am quite blessed to have this as my first dongle. I am not as well-versed as Andy but I will try my very best to share my unbias and honest impressions here.

Questyle is a company based in Shenzhen, China that specializes in quality amps. One of their product that is critically claimed by audiophiles is the CMA fifteen. This is my first encounter with them and I have not yet dived into their products. But by the looks of it, the company is low-key but makes exquisite and reference-grade releases. They don’t have a vast line-up but I think making it count is what matters to this company. Below is their website in English and feel free to roam around to know more about them.

Special mention: I would like to express my deepest gratitude to Zach from Questyle for entertaining my queries and being nice and generous to me. He is the Product Experience Manager over there. You da man Zach!

With the M15, I would like to quote the concept of Questyle.

“In this complex world, we pursue simplicity.
The era of 5G has brought music streaming from smart devices fully into the mainstream. As more and more music platforms launch lossless audio streaming services, mobile hi-res audio has changed from a neat gimmick into a real and growingly popular way to enjoy high-fidelity music. However, it’s often impractical to use traditional HiFi audio equipment with your smartphone on-the-go, due to size and power consumption. To solve this problem, the M15 was born: it distills all of Questyle’s expertise and technologies into an amazingly powerful yet compact mobile DAC & amp.
Don’t be fooled by its small size. The M15 offers uncompromising performance and best-in class fidelity, giving you the ultimate portable audio experience.
Welcome to the world of truly mobile HiFi.”


My opinions here are entirely my own. Any form of incentive does NOT in any way influence me. This is purely my honest, subjective impressions and experience with the gear on hand. I cannot stress more that you should take this with a grain of salt for we have different perceptions to sound and what we hear. I always try my best to stick with the stock accessories that come with the gear by default. You are free to try other methods such as tip rolling or cable rolling. Below are worth noting before concluding on what I say here:

  1. DAP (digital audio player, be it phone, laptop, mobile, or stationary setup)
  2. DAC or dongle or any external amp
  3. Ear Tips
  4. Cables
  5. Source of audio file be it offline FLACS or streaming services like Deezer, Apple music, Tidal, Qobuz, Spotify and the likes..
  6. Your playlist. It matters and is worth considering when reading from a reviewer's perspective. It is apparent that you get to know your favorite reviewer and what they are listening to leisurely and critically.

My reviews are more on how music sounds in my ears. I leave the technical stuff like frequency graphs and the physics behind the tech and drivers used to other reviewers.


  1. DAC capability:
  • PCM: 32khz - 384khz (16/24/32bit)
  • DSD64 (1 bit 2.8mhz), DSD128 (1 bit 5.6mhz), DSD256 (1 bit 11.2mhz), MQA full decode
  1. Output power:
  • 3.5mm: RL=300ohms, Po=11.97mW, Volt (max) = 1.895 Vrms
  • 4.4mm: RL=300ohms, Po=22.60mW, Volt (max) = 2.624 Vrms
  1. Frequency response and THD:
  • FR: +0.1db (20hz-20khz)
  • THD + N: 0.0003%
  1. DAC: ESS flagship USB DAC chip ES9281AC



The outer box gives a premium feel to it with a very minimal design yet elegant. The box has good corners. The inner box slides to the right and you are greeted by documentation with Questyle’s concept on the product (mentioned above) and product usage. Then a warranty card underneath. After that, the M15 itself was placed in the middle. Another layer is underneath where the 2 cables are. 1 x USB A to type C. 1 x type C to type C. Questyle took the liberty of being extra generous and sent me 1 x Lightning to type C cable making it possible to enjoy this on IOS devices. You can purchase this for an additional price as it is an optional inclusion. And another bonus from Questyle, they’ve included the leather protective case that they gave for free on promo in the month of May if I’m not mistaken. A red colorway was given to me.




Physical attributes:​

The M15 is a unique-looking dongle. Oozing with elegance and sophistication. The look-thru glass gives it away. It is the only dongle I know of, that has this design. Let me show you all its physical attributes with photos. A photo is worth a thousand words.

Special note: The size of the M15 is quite large for a dongle and to be honest, it is not for an on-the-go setup. I can’t put it in my pocket along with my phone and it would be quite risky to let it hang with my phone, on commutes like the subway as the M15 has a decent weight to it. I’m the guy who moves around the house quite frequently and a lot of times I love doing my chores while listening to music. It is a struggle to move around with the M15 and I have to incorporate a belt bag to cater the M15 with my phone while doing my household chores like washing the dishes. Therefore, while the M15 still falls in the portable DAC category, I conclude it is still a semi-stationary setup with your phone.


The M15 has bread and butter features. It is not as fancy as other dongles with a screen where you can see the details of your track playing. But all the features that you need are here.

One thing missing here that I personally prefer is a physical volume adjuster. This is a minor caveat for me, but I understand other individuals who strongly prefer having this. Connected with my LG V30 phone, I don't mind it that much because I still adjust the volume level with the physical buttons of my phone. But if it were to be adjusted via a slider on the screen, it would have been a bit of a hassle.

A gain switch is present here. A very convenient feature. With my gears below 32 ohms, I use low gain, and for anything above 32 ohms, I use high gain. M15’s predecessor the M12 doesn’t have this feature.

Available outputs are a single-ended 3.5mm, and a balanced 4.4mm. Another feature the M12 doesn’t have. If you have been an audiophile for quite some time, we all know balance output exhibits more out of your transducers and this will come in handy with your gears that offer balanced termination.

Next are the light indications. There are two lights here. One indicates if you are on low or high gain. Green means low gain, and red means high gain. As for the other set of light, it indicates the quality or codec of the music you are feeding it. Green for anything below 48khz, red for anything hi-res, and magenta for full MQA encoding.

And that’s it! Pretty basic right? But it’s all you need to enjoy your music with this dongle. No fancy screen here with sick transitions whatsoever. It emits a sense of being analog if you ask me. Which I am a fan of. Techs of the past and how they presented back in the days, appeal to me. And actually, it is easier to comprehend. Just look at the lights and you instantly know the quality of the file you are playing.

Now moving on to how M15 performed on sound…

Sound impressions:​

Special Note: I’m a firm believer that source matters. A dongle enhances our listening experience because it is not integrated with the phone or laptop we are using as our source. It has an impact on the sound we hear but it is not the primary factor that alters what we hear. As an example, if you have a transducer with a slow driver performance, a dongle will not make the speed of that driver perform faster. Maybe it would be enhanced but in a very subtle way. The primary sound presentation still depends on the performance of the transducer.

IEMs used for the entirety of this review are the Seeaudio Bravery Red limited edition, Kinera Idun Golden 2.0, Bqeyz Topaz, and Autumn. More on pairings later on.

I will have a different format here addressing my sound impressions with M15. I will not dissect each frequency but rather lay them down as a whole along with the technicalities. Just purely expressing what I hear and the changes I hear compare to my other setups.
Ok straight to the point. The M15 is a “revealer”. Period. It reveals a gear, in my case mostly IEMs, strengths, and weaknesses. It has a neutral sound signature to my ears and with stupendous resolving capability. Not limited to gears, M15 reveals properly and poorly mixed tracks. I can’t say if this is a blessing or a curse, but there are tracks that I enjoyed before, that I don’t enjoy that much now, all because M15 showed me that it is indeed a poorly mixed track. Though not the most powerful dongle in town, it can handle most IEMs and some M15 owners have claimed that it can drive some headphones. Well decently at least. I still have to venture into headphones territory to back this up, but I do have one. A Samson SR850 32 ohms, and I’m listening to it as we speak, and I’m around 70% level giving me a good listening level.

The overall sound reproduction is crisp, transparent, and with brilliant transient speed. Neutral sources tend to be sterile and dry but M15 doesn’t present its sound this way. It remains organic, enjoyable, and with a wide dynamic range.

Mids and vocals made the most distinguished mark on me. Lush, rich, and rendered with good emotion. I’m a passionate musician, and I like my music moving me to places when I listen to them. M15 never had shortcomings in this department. Instruments sounded the way they should be and never felt artificial nor unnatural.

The lows are presented truthfully without any colorization with a snappy, and quick reproduction. I listen to a lot of jazz tracks, as I tend to look at how natural a gear can execute instruments in this genre and the lows are pinpoint. What you give the M15, it faithfully reproduces as natural and pure as it can.

The trebles have a slight elevation as I critically listen. Some of my gears appear to have added shimmer and sparkle on top but not at the expense of being sibilant.

The sound stage is above average. If I have to nitpick, it could use some extra expansion but negligible. I find my LG V30 via Hiby music app a bit ahead in terms of the sound stage but we’re talking minuscule difference here.

Separation is spectacular and I can conclude that elements portrayed by M15 seems to be laid down with good spaces in between them. Hence making it very entertaining to listen to. I find joy in deciphering what each instrument is contributing to the whole piece when listening to my favorite jazz tracks and M15 delivered effortlessly.

Imaging is brilliantly done as it places elements with accuracy. I can easily follow instruments let alone micro and macro details with good depth, width, and height as was intended by the engineers and producers.

Resolution and detail retrieval is the pinnacle attribute of M15 as I clearly hear small details and texture of instruments. Guitars portray their string vibrations, pedal presses from piano players are brought to light, and vocal strains of singers can be heard, strikes of drum sticks and hand slaps of a percussion player are just a few to mention. There are many details here so be prepared to hear new elements from tracks you know too well.


First off let’s start with the battery consumption of M15 with my phone. It is very energy efficient and doesn’t drain the hell out of my mobile phone. I mainly use the LG V30 for my offline flacs. I can enjoy a good 4 hours of playback and maybe even more if I’m not multitasking. This might be not enough for some but in my case, it is doable. If you prefer longer hours of playback, then a DAP will be more suitable for your needs. Or maybe a separate mobile phone solely for music playback will do.

LG V30 quad dac x Hiby player music app​

The performance of the M15 is very smooth here. The floor noise is clean as black. Integration with the app is flawless. The Hiby app easily recognizes the M15. I run with exclusive mode on. No popping sound whatsoever when changing tracks. This is my main setup for mobility and portability.

Via UAPP:​

Smoothly integrated as the Hiby music app. With UAPP I find the sound a bit brighter. User interface responsiveness is also slower than the Hiby music app. Well, we are not here to discuss and compare the two mentioned music player apps. Let’s just say I personally prefer the Hiby music app. Nonetheless, the performance of the M15 is the same with the said apps.

Via Tidal on Android mobile phone:​

Still flawless and the app works with the M15 smoothly. Tidal Masters is indeed legit as the M15 emits a magenta led light when unfolding MQA. The Tidal app also offers an exclusive mode. Very handy. The app works with the M15 without any issues or hiccups.

Via Apple Music on mobile phone:​

Here I encountered some issues. In particular with running on an Android phone. I can hear some popping sounds in the background. Very unnoticeable in playback, but you will notice it when you are not playing anything. And by a big margin, the output is much softer. A more enjoyable experience with this app is on an IOS device. With my iPhone 7 plus, the output is much more accurate and louder. I did not use an OTG for this connection as the lightning to type c USB cable was provided. This comes as an optional accessory if you were to purchase the M15. If you stream mainly with Apple music, do it on an IOS device. Strongly suggested.

Via Macbook pro x Tidal:​

This is my go-to stationary setup. Exclusive mode is also available as with the mobile version. When I’m in the mood to explore and discover new tracks, this is my favorite. If you are not a believer of MQA, there is also a bypass option to do that. One caveat is when I’m seeking (forward or backward) an evident popping sound is produced. Not a deal breaker, but I often seek within my tracks especially if I’m critically listening to some parts of a song. Integration of the app here on a Macbook pro with the M15 is also smooth and with almost no issues.

Via Macbook pro x Foobar:​

This is my setup to access my offline flacs on a stationary setup. UI of Foobar is very basic and navigation is quite a pain. I like keyboard shortcuts but with Foobar on a Mac, is very primitive. The trackpad or mouse will be your best friend as everything will be done with it. Playback and true encoding of your Hires files are legit. Volume control is handled by the Mac OS. The volume up and down is very convenient so no dragging of the volume slider here, which I personally hate and is cumbersome for me. Performance and integration are legit with this app. UI just needs to be updated. I am eyeing the Roon but I need to research more on this.

3.5mm versus 4.4mm:​

The performance of both outputs is actually decent and commendable. Both possess excellent outputs and there is no reason to discriminate the 3.5mm over the 4.4mm. Balanced output is balanced and better in terms of dynamics, loudness, technicalities, driving power, and overall sound presentation. If you have the means to plug into the 4.4mm, please do. Nonetheless, 3.5mm is still very capable and not to be looked down upon.


I will mainly compare the M15 with my second source, the Hidizs ap80pro. This comparison is done with Kinera Idun Golden with the same song, approximately the same listening level, and on high gain mode since the Idun loves power. AP80pro running standalone, and the M15 is paired with an LG V30 android phone via the Hiby music app. Conducted both in 3.5mm single-ended output.

Track: Fool Truth by UDD, a local artist from the Philippines, mix and mastered abroad. I know this track too well, so I picked it for this comparison.

  • The floor noise on the M15 is much lower than on the ap80pro.
  • The ap80pro had more width, and the M15 had more height.
  • Listening level concerning driving power. M15: 8/32 (25%) ap80pro: 43/100 (43%)
  • The bass guitar in the intro is more textured and forward with the M15.
  • Vocals are more forward with the M15, with more details like the singer's pronunciation.
  • Both exhibit neutral sound presentations.
  • Drum kicks are punchier with the M15.
  • Vocal and instrument separation is better on the M15.

Conclusively, the M15 performs better on technicalities compared to ap80pro. The sound signature is almost the same on both gears. The M15 has a more pronounced mid-bass. The M15 outperforms the ap80pro by a noticeable margin. Still, both gears are very capable and exceptional for reviewing gears. Almost to no colorization and alteration on sound.


With Kinera Idun Golden​

Idun being a neutral set surprisingly paired well with the M15. I anticipated that this pairing will be too clinical or boring but that is not the case. The M15 brought the best out of the Idun, especially on technicalities. Not to mention the big improvement once used with the 4.4mm balanced output. This pairing is not void of being enjoyed particularly leaning towards the Hi-fidelity approach. Visit my full review of the Idun here:

With SeeAudio Bravery Red limited edition​

The Bravery is a more engaging pair with the M15 than Idun. A more colorful sound signature but maturely tuned. With exceptional imaging and instrument placement, the M15 brought it to another level. A perfectly balanced pair that is hard to ignore and neglect. The Bravery opens up significantly with balanced output. If you have a 4.4mm termination, put it to good use right now. The Bravery is very easy to drive with an 18 ohms of impedance. You might want to switch to low gain mode to avoid distortions.

Full review of the Bravery Red limited edition:

With Bqeyz Topaz​

If you want to go warm, relaxed, and yet technically capable set, the Topaz is one of my favorite pairings. I was once on vacation, and I brought the Topaz with me forcing me to listen to it for a couple of days since I have no other IEMs with me, and this is the most organic and musical pairing in my collection. The neutrality and clinical nature of the M15 compliment the warm and lush sound of the Topaz. When I’m in the mood for just relaxed listening, this is my go-to pairing.

Full written review of the Bqeyz Topaz:

With Bqeyz Autumn on neutral filters​

If I’m in the mood for that extra sound stage, I go for the Autumn. The wide stage of Autumn compliments the somewhat intimate stage presentation of the M15. As per the sound, the Autumn sits nicely in the middle of the three IEMs above. The most balanced pairing of all. The Autumn boasts its earbud-like sound stage. And I just can’t get enough of it with this pairing.

Full and written review of Bqeyz Autumn:

I have other IEMs in my collection, but these 4 will do as they are my most loved and “cannot live without” sets. All aspects above are very subjective. Please take it lightly with a grain of salt. Your mileage will most likely vary.

Minor Issues:​

As it breaks my heart to address some issues on an impressive gear, I still decided to include the following in this review. It has been a topic among us owners of the M15 at a thread at head-fi. It is regarding interference or what they call EMI noise. To be honest, I didn’t notice this until just recently. And yes the M15 emits a noise that is caused by cellular data from our phones. There are 2 ways to eliminate this.

  1. If your phone is connected to Wifi, you’re good. No interference.
  2. Turn on airplane mode.

The downside here is if you stream your music a lot, using cellular data, then you’re in trouble. Some owners are concluding that the M15 has poor shielding on interference from outside. Now even if I’m playing my offline flacs, but my cellular data is on, and not connected to a working Wifi, yes I have the interference. I have an attitude of being a purist when it comes to my music, and I’m really downhearted to experience this.

Personally, I mainly stream my music with Tidal on my laptop, and with this setup, fortunately, no EMI noise is audible. So for those who stream their music on the go, you might want to consider it first before pulling the trigger on the M15. But as I concluded in this review, the M15 is awkward to use on the go. So most likely, you will use the M15, on Wifi, streaming. You are safe if this is the case. Do be aware that the EMI noise is very minimal. It easily drowns out when you are playing your music. It’s just I’m a purist somehow, that knowing something is in the background, bothers me.

I would like Questyle to notice this issue, so they will consider it with their future releases, and potential successor of the M15. Questyle, please take this into consideration strongly.



The invasion of the dongles was mind-blowing in the audio community. I would like to commend AndyEF aka OspreyAndy for his #donglemadness for pointing me in the right direction. He saved me the trouble of going all through the almost hundred releases of dongles out there.

What caught my interest in the M15, to be honest, is its looks and design. Let us admit it, if it looks good, we hope it sounds good too. Apart from looking sleek, the M15 is my best experience in terms of source. My best one yet. I’m a technical-oriented listener, for the main reason that my main profession is being a pro-gigging musician. I always have a sweet spot for critical listening and I really have a high benchmark even if the sound is towards clinical presentation. But the M15 is not at all like that. It has rich dynamics, soul, and emotion portrayed character. It is just a very neutral and transparent sound presentation.

Driving power is very decent although not the most powerful dongle in town. It is surely an upgrade from my Hidizs ap80pro. M15 at 25% listening level while the ap80pro at 43% listening level. Driving full-sized cans I still have to explore. I have an Audeze headphone on the way, maybe 2 weeks from now, and I will update this review once I pair the two.

As for portability, I have some caveats on this. My listening setup with the M15 is somewhat a semi-stationary one. It is too large and heavy to be left hanging with my phone on commutes and is awkward to move with it while I’m moving around the house doing my daily routine and chores. It is not a true on-the-go setup in my case.

Anyways I don’t want to repeat what I said in this review so I would advocate the M15 to those:

  • Who prefers a neutral source
  • Who has a priority on technical aspects
  • Who loves critical listening
  • To reviewers who need to accurately judge gears
  • To those who want to be rest assured that what they are hearing has no color added
  • To those who want a resolving source

And that concludes my review of the M15! Again this is my best source yet! And as for reviewers who have more expensive source gears, they say that this punches way up to the caliber of 500$ price range sources. And you can enjoy that kind of quality for half the price! The M15 retails at 250$. I hope you enjoyed reading my impressions and a video version of this will be out soon.

Special mention to Eric Lab for putting a good word for me with Questyle giving way to getting my hands on the M15.

As always, love the music more than the gears! And your mileage may and most likely vary. Cheers, and catch you on the next one!


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Great review. I rarely use cellular data therefore never noticed EMI issue. Mildly disappointing given its the best dongle being sold right now, toppling even mid fi desktop setups
Great review.

This is a fantastic device that can in some cases blow past mid range home setups and at such a small compact size that is a real feat of engineering, I appreciate you bringing up the EMI noise issue while a lot of reviewers would skip over the issue or did not test for it, at the end of the day this is marketed as a portable solution and a lot of people would be streaming music on the go via mobile data and not have offline libraries that clog up memory on your phone.

For an offline library I personally would prefer a DAP for on the go rather than using a dongle, a dongle imo is meant for on the go streaming music so you don't have to bring another physical device or your entire offline library with you. It is supposed to be easy, effortless, plug and play option that takes up little space whether thats physically or in terms of memory space on your phone.

P.s. this is how I feel on the matter and may not be what the majority of people are thinking.


500+ Head-Fier
Questyle M15 USB DAC/Amplifier: Arisen my senses!
Pros: Design - that glass top is a striking choice
Balanced sound
3.5mm and & 4.4mm outputs
Cons: No physical volume buttons
Glass top makes me worried about transporting it outside of a good hard case
The M15 was sent to me by Questyle after I reached out about another product. Many thanks to @Questyle for facilitating this. I am not expected to return the product and this will not influence my opinion of it or Questyle in any way.


It’s in Our Hands:
OnePlus 6 & Neutron Player
ER2XR, 4.4mm balanced stock cable, Westone foam tips
TRI I3, 4.4mm balanced silver cable, foam tips
Playlist made up of MP3, FLAC and DSD256 tracks.

The M15 arrived in a black matchbox-style cardboard box, USB C cable, USB A-C cable and a brief diagrammatic manual. A green leather case was included and fits very snugly. So well that I cannot remove the M15 at all! I’m sure it would come out if required but would take a bit of gentle persuasion. The glass top shows off the circuitry and 2 status LEDs for sample rate and gain. There is a hardware gain switch on the side.

I listened to the whole of each track but specifically for the timed parts mentioned. I used the balanced output in low gain.
  • Happy Cycling | Boards of Canada - from 5:06, percussion and bass synth
  • Waters Deep | Bent - from 4:45 bass line, female vocals and higher register synth
  • Man (Live at the NEC) | Level 42 - from 2:20, Allan Holdsworth guitar solo
  • Play Me (Live at Reading 2001) | Level 42 from 3:57, bass guitar solo, electronic bass
  • Two Solitudes (album version | Level 42 - from 2:42, acoustic guitar solo
  • Peace Bird | Genius of Time - from 2:38 grinding sub-bass refrain then 4:40 sub-bass line, percussion
  • On a Clear Day | The Peddlers - from 1:00 strings and harp
Desired Constellation:
There is an extended sub bass (not something the ER2XR is particularly known for) with a surprising but very welcome touch of viscerality. Percussion is clean, not splashy or sibilant which can be an issue if the source or recording is neutral or bright. Male and females voices are natural, if a little thin. Similarly, guitars and keyboards are tonally correct but lacking slightly in body. I did not feel that there was a particular emphasis in any register and the M15 was showing me what the ER2XR could do. With silicone tips I noticed a cleaner sound with less bass warmth.

TRI I3: This has a mild U-shape FR and the M15 allowed it to shine. The soundstage is wide (a valuable property of the I3) with clarity, focus and separation. Again, the sound was clean and slightly warm, with visceral sub bass, smooth vocals and extended treble. In essence, exactly what the TRI I3 should sound like.

Mutual Core:
I hope that you get a sense of where I’m pitching the M15 in terms of sound. I feel it is balanced, detailed and natural. The music I listen to sounds faithful, uncoloured and tonally correct. The transducers I used gave an accurate account of themselves with nothing added to or subtracted by the M15.

Holographic Entrypoint:
For comparison, I fired up my Cayin RU6, a completely different beastie. Balanced output, low gain, non oversampling mode. The hardware volume buttons are a very welcome feature. The RU6 soundstage is far wider than the M15 with a warmer, darker tilt to the sound. That isn’t to say that it isn’t detailed, just differently so. Notes are fuller, sweeter and just…beautiful to listen to. The analogue bass of the BoC track is a great example. I notice smoother transients with some loss of attack and bite to guitars and synths. Vocals are smooth and warm as you might expect. The registers just have…a density and weight that is difficult to describe but so joyous to experience. The RU6 is equally superb but in a totally different way. I use it at my desk and took it to Canjam as a cross-reference. This is like a full-bodied stovetop coffee from Brazil.

Generous Palmstroke:
The M15 is a fresh, clean and natural sounding device that shows you the best of your earphones. I used it on my desk and took it to the London Canjam as a representative source. I liken it to a fruity V60 pour-over coffee from Ethiopia.
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100+ Head-Fier
Questyle M15 : Best Performing Dongle... Redefining dongle performance!
Pros: + Small & Pocketable
+ Transparent design and posh looks
+ 4.4mm balanced connector support
+ Separate Low & High gain modes
+ SIP & CMA resulting in significantly cleaner & transparent output
+ Class AB amplification which is rarely found in a dongle
+ Can easily power IEMs and a lot of headphones
+ Excellent Staging & Imaging
+ Superb Separation
Cons: Literally nothing I could find!
Questyle M15 : Best Performing Dongle... Redefining dongle performance!


Summary & Objective:

The @Questyle M15 is the second dongle release by Questyle in 2022, with balanced 4.4mm support and comes with some great features such as SIP and Current Mode Amplification which are generally found in portable players. It promises excellent performance and delivers exactly as promised and more.



The @Questyle M15 comes with excellent build quality and superb sound performance - not mentioning any price brackets here as soon you will find that it's performance goes way beyond it's price. It is the first ever dongle to feature SIP and Current Mode Amplification featuring Class AB grade amplification .
The Questyle M15 is priced at $249.



This unit was sent by @Questyle for the purpose of an honest review.
Everything mentioned in this review are purely my own based on my experiences with the Dongle DAC/AMP.


Design, Build & Features:

I wouldn't want to make this a very long review by describing each feature but for people who want to know, here are some extracts from the Questyle website.




The Questyle M15 comes with $249 price tag and the specifications are as below:

Questyle M15 uses all of Questyle’s expertise and technologies into an amazingly powerful compact mobile DAC & AMP.







Items Used for this Review:


IEMs of different ranges:
below $300: Kinera IDUN GOLDEN, 7Hz Timeless, @MOONDROP CHU, TINHIFI P1MAX
$500-700: @CampfireAudio Holocene
$800 - 1500: @Sennheiser IE600, @DUNU-Topsound ZEN PRO, @CampfireAudio Dorado 2020, @Audeze Euclid
$1500 - 2500: @UniqueMelody MEST MKII, @Softears Turii Ti
$3000: @Vision Ears EXT

Well these are the ones I have with me presently... and have used for the review.

Source : iPad Pro, iPad Mini 6, iPhone 13 Pro max, Laptop
Streaming Source: QOBUZ


Tracks Used:
The tracks I have used can be found from the below playlist that I have used and generally use for most reviews...


QUESTYLE M15 Sound Impressions in Short:


Despite the ESS DAC based architecture, the M15 has a very neutral tonality while ensuring clear, crisp & transparent sound delivery.


The Bass sounds just Superb. Bass has details in the sub-bass region and is thick and creamy with enough muscle in the mid-bass to make the instrument attacks sound very natural and realistic. In tracks like : "Anna R. Chie (Remastered) - Konstantin Wecker" and "Dreams (2001 Remaster) – Fleetwood Mac" you can feel the the deep attack of the different instruments with just enough details. The thumps and slams are very enjoyable. The layering & separation is also superb and you can distinguish each instrument from the other one easily.


The Midrange is excellent in terms of every single element. It is able to produce an good creamy smooth and textured midrange that is soothing to the ears while having enough details and layering in it. The vocals are natural and both male and female vocals come with good amount of details. Instruments sounded natural and can be identified easily from the other instruments owing to superb separation capabilities. In tracks like: "Anchor - Trace Bundy" and "Ruby Tuesday - Franco Battiato" while you will love the overall midrange specially transients of the guitars, violins etc... instruments and the vocals.


The Treble is very natural with enough extension & air as the track commands. It has enough details and despite being very natural it doesn't come with any harsh peaks in the treble region.


The staging and resolution is excellent and significantly better than any other dongle that I have come across so far. Resolution is also better than any other dongles and provides a very transparent representation while maintaining clarity and sense of direction. Tracks like: “ She Don't Know – Melody Gardot” or “Bohemian Rhapsody (live aid) – Queen” sound good & enjoyable. In this category this can rival many $500 - $800 DAPs easily.


This is clearly a competitive advantage for the M15 with the SIP and Current mode amplification, it is able to provide class AB or better quality amplification which is miles ahead of any other dongle in whatever price bracket.

The M15 makes an ideal pair with just about any IEM. It pairs well with each & every IEMs that I had tried from the various price ranges and various traits.



Based on many people's request, I had been able to compare the M15 with 8 other dongles on which I had done some facebook posts in the head-fi group already.
Links to those posts are below:

I will not go through much details here and will basically be summarizing my impressions based on the different


The Contenders:

The 8 dongle contenders against whom I have compared the M15 are below:
Below list is random and not based on any particular trait...

- @iFi audio Go Blu : $199
- @iFi audio Hipdac 2 : $189
- @iFi audio Go Bar : $329
- LUXURY & PRECISION W2-131 : $319
- Cayin RU6 : $249
- @Shanling M3X : $399
- XDUOO LINK 2 BAL : $149
- DDHIFI TC44C : $119

Here, as you can see the @Questyle M15 falls in between the price ranges above priced at $249 and is closest priced to the Cayin RU6.
The @iFi audio Go Bar and LUXURY & Precision W2-131 are higher priced, while others are priced lower. I have kept the Shanling M3X DAP also as that comes in similar price range and close to the iFi and L&P ranges at $399.


I will not be ranking the above mentioned dongles here, rather I will be sharing comparative impressions with the M15 here.


Below $200 Range:
The following dongles fall into this range: DDHIFI TC44C, XDUOO Link2 BAL, iFi Go Blu, iFi Hipdac 2. None of these dongles are as resolving or can provide as clear and transparent presentation as the M15. In terms of Staging, Imaging & Separation the M15 is significantly ahead.

$200 to $300: Only the Cayin RU6 and the M15 fall into this category. both are superb performers and I love them both, However, the M15 excels in terms of clarity and transparency and also in terms of staging and separation.

Above $300: The L&P W2-131, iFi Go Bar and the Shanling M3X fall into this category and are more expensive than the M15. While some of them might be more powerful in terms of specs than the M15, the quality of amplification in the M15 is significantly better than any of these and the difference is quite easily audible.
The level of clarity & transparency that the M15 brings onto the table is truly superior and also the level of saturation and sense of direction in the imaging department. This is not to say that the other dongles are not good... Just that the M15 is audibly better.


Conclusion :

After comparing all those dongles above, if I have to pick one based on my preferences, I would pick the M15 in a heartbeat. It is significantly better than any dongle that I have come across till date and redefines the performance expected from a dongle..
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I have meze 99 classic with fiio x5 ii+ fiio e12, and I was thinking to upgrade. Thinking to go for a dap about 700 euro or a dongle (questyle m15) using with phone, what is better option, I listen pop disco rock hard rock heavy metal. With my fiio duo now have very punchy deep bass, which I want to keep it with my new purchase, but also want the most juice from my meze. Thanks for your review and your time
@fotis1972 Though I don't have the gears you mentioned, in my own experience - I had found M15 to pair well in most cases if not all.
@fotis1972 M15 would be the best bang for the if you have no iPhone. The current Limitation on iPhone lightning connectors will ruin the Experience if you need something around or over 400mA out of the Phone.


The Little Dongle That Could
Pros: 1. Reference grade sound
2. Detail retrieval
3. Dynamics, Extreme precision
4. Excellent sibilance control
5. Extension
6. Brilliant heat and battery drain management
7. Manual gain switch
9. Punching far above its price point
Cons: 1. Soundstage is just adequate
2. No lightning adapter
3. Provided cables are very stiff
(The pros far outweigh the cons/nitpicks)
Dongles have suddenly skyrocketed in popularity after Apple decided to ditch the headphone jack in favor of airpods (which worked flawlessly as airpods generate unbelievably huge amounts of revenue and profit for Apple) and the whole smartphone industry followed suit. Initially there were only budget options; Cheap, decent but also rough around the edges and underpowered. But in recent months, we have observed a sudden boom in ‘premium quality’ dongles costing 150-400 USD that are somewhat blurring the line between ultra portability and mid fi desktop class sound.

That being said, Questyle M15 is probably the best all rounder in the premium dongle class right now. Questyle, although a bit obscure in the crowded Chi fi scene, has never made a product that isn’t great. Their first foray into the ultraportable dongle market was the underrated but amazing for the price M12, which I preferred to iFi Hip DAC even. M15 is the full fledged evolution from M12 to a far more capable, incredibly impressive little device.



This unit was sent by Questyle to Sajid Amit, reviewer at Amplify Audiophile Show. I work with Amplify and what follows are thoughts and opinions that are solely mine.

Unboxing, build quality and ergonomics:

Unboxing experience is great. Comes in a simple and minimalistic black cardboard box. 2 short USB cables are included. One USB A to type C and another is type C to type C. Build quality is as expected from Questyle, Sublime. Extremely good finishing all around, fabulous weight distribution and skin feel. Both 4.4 mm and 3.5mm connectors feel solid and premium.

Aesthetically M15 is probably the most unique looking dongle out there right now. Internals are entirely visible through the acrylic window on one side. This gives the M15 a very nerdy, over the top yet refreshing look (internals are neat looking as well, adding a massive bump to the overall aesthetics).


M15 is a bit bulky for a dongle but the weight distribution, like I’ve already mentioned, is excellent, therefore ergonomics was never an issue for me.

Important Features:

M12 was great but had a few feature flaws that have been addressed in M15. M12 had automatic gain meaning low sensitivity low impedance headphones and IEMs would trigger low gain when high gain is necessary. M15 has a manual gain switch that can be flipped anytime to make itself compatible with all the headphones and IEMs it can power. Another big addition is the 4.4mm balanced out which is incredibly powerful for a small form factor device (will discuss in detail later). M15 supports fancy codecs like MQA and DSD and it’s a proper MQA decoder, not a renderer. Therefore a good option for MQA believers.

M15 is also modular meaning you can use any compatible type C cable you like on a large variety of devices



  • DAC Capability:
    • PCM: 32kHz – 384kHz (16/24/32Bit)
    • DSD64 (1 Bit 2.8MHz), DSD128 (1 Bit 5.6MHz), DSD256 (1 Bit 11.2MHz) MQA Full decode
  • Output Power:
    • 3.5mm: RL = 300Ω, Po = 11.97mW, Volt (Max) = 1.895 Vrms, THD+N = 0.00045%
    • 4.4mm: RL = 300Ω, Po = 22.60mW, Volt (Max) = 2.624Vrms, THD+N = 0.00057%
  • Frequency Response and THD:
    • Frequency Response: ±0.1dB (20Hz-20kHz)
    • THD + N: 0.0003%
  • DAC: ESS flagship USB DAC chip ES9281AC
  • Output Interface -
    • 3.5mm standard headphone jack x1
    • 4.4mm balanced headphone jack x1

M15 is the most reference sounding premium dongle right now period. The first thing I noticed immediately was the sheer transparency and details it was pushing. I couldn’t believe I was listening to a dongle and not a full fledged mid fi desktop device. What's most impressive is that this transparency and neutrality doesn’t come at the expense of musicality. Yes M15 is high res and highly analytical but the common denominations associated with these qualities like sterile and dry don’t apply here, at all.

Bass is one of the best I’ve heard in DAC Amp regardless of price and really brings out the best from what your headphones/ IEMs are capable of. There is no exaggeration, no bump in any bass frequencies. Just full bodied, snappy and accurate bass with brilliant extension. For example there are not many DAC amps especially under 1k that can do justice to Focal Utopia’s bass capability. But with M15, the full potential of Utopia’s extremely dynamic and fun bass reproduction is unleashed. I had similar results in bass performance with every other pairing I tried.

Midrange is lush and full bodied but there is no coloration. This is a very hard feat to pull off but M15 does this effortlessly. This results in an even performance between male and female vocals. Instrument timbres present in the midrange also sound as they should in real life, accurate and natural.

The brilliance of midrange and bass continues further in the treble region. If I have to describe the treble in 3 words, those would be extended, precise and controlled. There is no unnatural boost to any region to pump in artificial air, no digital sheen resulting in plasticky, glassy edges all over the music. Nailing the treble region is what's missing from most dongles from my observation. They are often treble boosted in order to generate a sense of detail and air, or too polite making everything dull and boring. M15 is probably the only dongle that blurs the line between precision and musicality in the treble region with resounding success

Technical performance:

M15 is a monster in this regard. Imaging is stupendously good and so are separation and layering. I can pick up every single instrument, every single layer in the vocals and bass but it's effortless and never becomes a chore. Dynamics and speed is easily among the best I’ve heard under 1000 USD regardless of form factor. My only gripe here is the soundstage which is adequate but not very large but it’s a miniscule issue in my book and not noticeable unless you frequently AB between different DAC amps that sound wider.

Driving power. Heat management and battery drain:

M15 is an anomaly if power and battery drain is considered. It can power almost anything except outliers like Susvara, HE6SE Abyss ETC. On high gain and balanced out, I can hardly turn up the volume beyond 30/40 on Arya Stealth and Edition XS. And by driving power I mean driving properly, not just driving loud. M15 adopts Questyle’s bespoke current mode amplification tech which uses CMA modules instead of traditional OP amps. Therefore, actual driving power is much higher than the specs suggest. I also like how M15 doesn’t gimp SE out in favor of BAL. Both are equally good and the only difference is in power and to some degree, separation (barely noticeable).

Heat management is exceptionally good. It doesn’t get hot/warm at all on low gain and heat management in high gain balanced out is still impressive. Gets slightly toasty and warm but never alarmingly hot like many super compact DAC amps and dongles tend to do.

Battery drain is minimal despite its exceptional driving ability. This is a highly overlooked advantage that premium dongles often fail to nail. Minimal drain means massive boost in practicality and battery life of the host device. M15 does a fantastic job in this regard


Being reference sounding means synergy will be good with almost all headphones and IEMs out there. The way M15 handles and mitigates sibilance and uneven peaks bolsters that even further. Almost all my headphones and IEMs that could be powered by it sounded great. It performed extremely well with both Arya SE and Edition XS and every single I've thrown at it including IER M9 and Legend Evo.

My friend and mentor Mr. @Sajid Amit even tried his Abyss AB1266 phi TC on it and white it didn't perform to its full potential, performance was still more than satisfactory


Minor gripes:

Glass window is cool and all but glass is glass and glass breaks. You need to be extra careful. My personal solution to prevent fingerprints and scratches was buying a random hydrogel protector for smartphones (dirt cheap), cut it to size (6 cm * 3.2cm) and applying it on the window. There is a pre installed screen protector already present though but being cautious always pays.

2. No physical volume adjustment. Not necessary in my book though. Controlling volume from smartphone is more ergonomic and you can always control volume via keyboard or mouse side buttons on pc

3. Provided cables are very stiff albeit robust. Softer materials would’ve been more ergonomic

4. Too perfect to nitpick any further lol


M15 blurs the line between ultra portable and mid fi desktop performance. I'd even like to hyperbole a bit and say its a proper high end Hi fi device. A true champion and breakthrough in the ultra portable Dongle DAC amp scene. Kudos to Questyle for making something affordable (relative to their serious stuff) and retaining their magic even in small form factors.
Yes M15 will be a significant technical leap. I generally run my Sony IER M9 off it and man, It sounds massive off M15. Like a full fledged kilobuck over ear. Also extremely good performance with Hifiman Edition XS and HD 650
I really like the way you describe what you hear here. Thank you for the review. I hope mine gets send soon. 😁
Thank you for your kind words. Hoping you'll like it :gs1000smile:


100+ Head-Fier
Questyle M15 Long Term Review
Pros: Very dynamic sounding and engaging to listen to
Neutral and uncolored sound
Plenty of driving power
Not analytical nor sterile sounding despite sporting neutral signature
Cons: Does not bundle with Lightning's adapter (Nitpicking)
Questyle M15 Long Term Review


Questyle is a brand I believe most audiophiles are aware of. They are famous for their CMA technology (Current Mode Amplification),you may read more about their CMA in this link if you are interested. Today we have M15 with two independent CMA SiP modules compared to M12 which is M15’s predecessor with only one SiP module. Today I will evaluate the performance of M15. Now,I may sound a little biassed and shilling this product,but trust me,once you have listened to it,it is very hard to put it away,of course,provided that the sound signature is your preference.

Specifications and Diagram (Grabbed from Questyle’s Website )

DAC Capability -
PCM: 32kHz – 384kHz (16/24/32Bit)
DSD64(1Bit 2.8MHz) , DSD128(1Bit 5.6MHz), DSD256(1Bit

Output Power -
4.4mm:RL=300Ω,Po=22.60mW, Vout(Max)=2.624Vrms,THD+N=0.00057%

Frequency Response and THD -
Frequency Response: ±0.1dB(20Hz-20kHz)
THD + N:0.0003%
DAC:ESS flagship USB DAC chip ES9281AC

Output Interface -
3.5mm standard headphone jack x1
4.4mm balanced headphone jack x1

Packaging/Build Quality
M15’s packaging is fairly minimalistic and elegant to me. No fancy layering and huge space wastage,it gets the job done and looks elegant and minimal. The package came with two USB cable,one type c to c,and another type c to type A. I received this unit during the promotion period hence it came with a leather protective case which I find it to be very good from protecting the unit from scratches.

In terms of build quality,the whole device feels very solid. Body’s panel is made out of metal and the front panel is a transparent cover which allows you to view the internals of the M15.Very nice looking piece of hardware in my opinion.


IEMs used
  • Letshuoer S12 (Planar)
  • TinHIfi P1 Max (Planar)
  • FAudio Major (Single DD)
  • Moondrop Aria Snow (Single DD)
  • Rose Technics QT-9 MK2S

Source used
Foobar2k -> Questyle M15
Apple iPhone 12 Mini Apple Music -> Questyle M15
Foobar2k -> TRI TK2

General Features
M15 is equipped with a gain switch which is a very welcoming feature that allows us to manually control the gain considering M12 does not have a gain switch but an automated switching instead.

M15 has got a see-through front panel which reveals the circuitry of M15,i personally like the appearance a lot. There are two LEDs which indicate whether M15 is on Low/High gain,and another LED which shows the data rate. Refer to the diagram under specification for more information.

Testing the battery drain of M15 on my iPhone 12 Mini,gotta admit it drains quite a bit of juice from my device. Do take into consideration that the iPhone 12 Mini itself has a smaller capacity battery.


Driving Power
Unfortunately,I do not own any headphones/IEMs that are hard to drive. Let’s just say it is able to drive anything that I own even on low gain mode. FAudio Major, TinHifi P1 Max,Letshuoer’s S12,

This is my first time testing out Questyle’s product.I have heard many great things about how good they sound across their product line. M15 is no exception either,to my ears,they are uncolored and fairly neutral sounding.Dynamic sounding but they are not sterile or analytical sounding.Very enjoyable and pairs well with most of the IEMs i have. Prior to writing this review, I have been using M15 extensively for at least 3 weeks on a day to day basis averaging 3-4 hours a day.

  • Clean,fast and tight bass,not muddy at all
  • Good texture/note weight and enough warmth for the bass texture
  • Sub-bass rendition on M15 is clean and not emphasised,it delivers the sub bass as it is. An example of slightly emphasised sub bass is on Xduoo’s Link2Bal,on the same IEM,it sounds different on both DAC/AMP in terms of the sub bass rendition
  • Very good impact and note weight
  • Bass doesn’t bleed into the mids and it is very capable in handling busy tracks like Slipknot’s Duality,not a tinge of muddyness spotted

  • The midrange reproduced by M15 is very lush and organic sounding to my ears,they are in no way cold sounding nor sterile,maybe titling to the warmer spectrum a little,at least to my ears
  • Both male and female vocals has got good textures to them
  • Instrument’s timbre such as piano sounds very natural to my ears
  • Upper mids are are not harsh and very pleasant to listen to

  • I find the treble on M15 to have good extension and non fatiguing to listen to
  • It has got plenty of details,both micro and macro but never at once it sounded too analytical to my ears,even when you crank up the volume,it remained very pleasant to listen to
  • Treble never sounded cold,instruments does not sound splashy at all
  • The air and sparkle region is also nicely reproduced

Soundstage and Imaging
  • M15 doesn’t reproduce an overly huge soundstage,instead i would say it is reproduced in a more accurate stage size,Xduoo’s Link2Bal for example,the soundstage reproduction certainly sounds bigger on Link2Bal compared to M15,but it does feel a little artificial and M15 does not made me feel that way
  • The soundstage reproduction has got good depth and height,but it doesn’t give you that kind of “out of head” feeling
  • Imaging is also very on point,instruments can be identified easily and layered properly

Comparison (TRI TK2)
  • Both M15 and TK2 sports DAC from ESS albeit different model
  • To my ears,I actually enjoy the M15 a lot more compared to TK2,TK2 to me sounded a little sterile and dry?
  • M15 is a lot more versatile when it comes to IEM pairing,it seems to synergize well with the IEMs that i have listed above,even some other IEMs like HZSound’s Waistdrum,TinHifi’s T1S,and even Final Audio A4000,WaistDrum and Final Audio A4000 on TK2 are not a good pair as TK2 kind of made both of them sound brighter than they already are
  • In terms of driving power,i believe both should perform on the similar level although i do not have any hard to drive gears nor any measurement tool to test it
  • In terms of soundstage, TK2 seems give a taller sense and slightly wider soundstage compared to M15
  • In terms of technicalities,they are more or less similar to my ears

Final thoughts
This is my encounter with Questyle’s product and now i’m hooked! It is very exciting to see such a product in a small form factor that’s capable of delivering reference class sound without breaking the bank considering the sonic performance that it brought along with it.

It’s safe to say,this will be my reference dongle dac/amp and I will be using it extensively for any IEM/headphone review moving forward.

Highly recommended piece of hardware and i will gladly give this a 5 star without any doubt!

*Questyle M15 was sent to me f.o.c for the purpose of this review, I thank Zach from Questyle for the opportunity. I am in no way compensated nor influenced to produce this review.

Questyle M15’s Product Page

Get one here! (Non affiliated)



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Headphoneus Supremus
A more than capable dongle
Pros: -Clear and neutral sound with lively dynamic
-Excellent Pace, rythm and timing (PRaT) performance
-Great imaging with open spatiality
-realist timbre with good transparency
-weighty dynamic
-clean linear current amping
-gain switch
-more powerfull than the specs suggest (75mw@32ohm)
-doesn’t get hot or drown battery too fast
-best ES9281C DAC implementation i heard
-great balance between technical and musical audio decoding
-versatile pairing with high sensitivity and high impedance IEM
-unique geeky design for circuit board lover
Cons: -while powerfull, it will struggle to drive very low sensitivity IEM or Headphones
-micro-definition isn’t the cleanest nor the sharpest
-bass and treble seem just slightly tamed
-glass cover can be scratched and is worrysome for durability
-protective case make it hard to use gain switch

TONALITY: 8.8/10

is a chinese high end audio company specialize in amplifier, DAP and DAC-AMP. They have been around since 2015 and are known for their high end DAP like the well receive QP1R and QP2R, as well as for their deskop amplifier and lately for their portable DAC-AMP (dongle).

Another thing that Questyle is know for, it’s their patented Current mode amplification technology, which permit to achieve class A amplification quality in a more compact factor. All their products use this type of amping circuitry which is acclaim by audiophiles.

Today, I will review their latest portable DAC-AMP release, the M15. Priced 250$, this mid-tier dongle use a sabre ES9281AC DAC with four CMA (current mode amplificator), which promise highly dynamic sound rendering as well as top of the line audio performance.
Let see in this review if the price is right for such a small DAC-AMP.


Unique you say?


The M15 have a very original design that is sure to catch the eye and even make you suddenly curious about audio circuitry. Its made of metal body with the top all made of glass that permit to see the whole circuit board, including dac and amps chips.


This design is wise too, since it have 2 light indicator on the board, one for data transmission and other for gain selection. Data indicator light color will change depending of codec rate, green for anything under 48khz, red for anything hi res between PCM 88.2kHz~384 kHz, or DSD64~DSD256 and magenta for MQA streaming. Gain light color will be green for low gain and red for high gain. This is very practical yet subtle in it’s presentation.


Rest of body is made of metal with a black mate finish. Front of the device have one 3.5mm SE jack and a 4.4mm gold plated balanced jack. The back have a USB-C connector. Left side of the body have a metal gain switch. Everything feel well crafted.

You can buy a leather protective case for 25$. In all honnesty, at 250$, i would have expect it to be include in accessories, which include 1 basic USB-C, one USB-C cable and one USB-C to USB cable and a USB-C to lightning cable . It doesn’t include USB-C to lightning cable, another potential extra cost for Iphone user.


Packaging is minimal, nothing really to write about and as noted, inclusion of a protective case would have been very welcome.

Lastly, about this protective case, i’m not sure of it’s exact purpose apart adding a classy touch to the M15, since the glass isn’t protected and will still be prompt to scratch or perhaps breaking if drop on the hard floor.



High gain 4.4mm: 72.72mW@32ohm – 1.525Vrms- THD+N=0.00139% Impedance= 1.22ohm

High gain 3.5mm: 42.25mW@32ohm -1.163Vrms- THD+N=0.00084% Impedance=0.96ohm

Compared to several portable dongles delivering 4vrms in balanced mode, the M15 may seem very limited with its 1.525Vrms in high gain balanced mode, fortunately this does not translate into impressions of loss of volume or dynamics because even the Sennheiser HD820 can sound full, open and loud with their 300ohm.

So, with my tests, I would conclude that this type of power limitation will be more problematic for earphones or headphones with low sensitivity than low or high impedance with normal or high sensitivity. For example, the Final E5000 have an impedance of only 14ohm but a very low sensitivity of 93ohm, which seems to conflict with the type of amplification of the M15 by not allowing the transducer to act correctly, which creates invasive distortion and compressed sound. This case of the E5000s is an exception and no other IEM or headphones have suffered this tragic fate.
Despite an output impedance that may seem high for very sensitive or low impedance IEMs, the rendering of M15 remains clean, balanced and without distortion for sensitive IEM, as the Audiosense T800 (9ohm) and Dunu DK2001 (110db-32ohm) proved it.
So my advice here would be to avoid earphones or headphones with very low sensitivity and maybe opt for an impedance of 16ohm and above to be safe. The M15 will have no difficulty correctly driving 99% of theIEM, earbuds and headphones on the market, with a power well felt in its dynamics and without distortion or invasive hiss.

The current mode amping technology used by Questyle is nothing like voltage amplifier using OPamp for extra gain.

''Current Mode Amplification features the use of transistors to amplify and a fully discrete structure, to wit: voltage input and output, while the core amplification takes place in the current domain operating in a pure Class A state. It is completely different from the traditional voltage mode amplifier in the structure of the amplification circuit. Current-mode audio amplifiers affect the speed and bandwidth of the transistor-level capacitance between the low impedance nodes, not only completely eliminates the transient intermodulation distortion (TIMD), but can easily attain ultra-high bandwidth (full power bandwidth of 500kHz ) and ultra-low distortion (lower than 0.0002% THD+N, challenging the physical limits of audio testing). The Current Mode Amplification technology can be used for amplifiers of any power level (10mW-2000W) and of any size (thousands of square centimeters for some professorial amplifiers).''

But how does it translate in sound perception? Well, imagine a THX AAA amplifier, like SMSL SH9, but with greater dynamic impact and denser more natural timbre, and your not far from M15 amping experience. Current drive seem to deliver power in a different way too, resulting in louder sound than it's 75mw suggest. I'm not sure to know how to explain this, but the fact it was able to drive correctly and without distortion or compression in dynamic the Sennheiser HD820 is sure impressive.




A neutral rendering but not flat in dynamics which it approaches more the W shape with an injection of weight and density in the low, medium and high. Everything in timbral and tonal balance is natural and cohesive. It’s not colored while being not clinical or cold in the rendering too, it borders on the analytical without having any spike or imbalance in the rendering of the frequencies which would harm the cohesion of the whole. It’s crisp yet well rounded balance.
Still, the widest frequency band is the highs and the M15 keeps this in focus, preserving its fullness of rendering and cleanliness of presence. In my opinion, here we are in the best of worlds where romantic musicality and a high degree of technical performance meet and embrace each other in complete naturalness.


With the M15, we are not in warm or dark territory, nor in artificial amplification of clarity, certainly the resolution is very high and will make you discover new details in the music you listen to, but without pushing them forward with aggressiveness or too much amplification of the texture to make their presence stand out.

Here, Questyle has drawn the full potential of its saber ES9281 DAC thanks to a clean, linear and varied amplification in its dynamics. Macro-resolution is favored here, it’s vast and detailed, transparent and revealing. The sound layers cut across spatiality while keeping intact the well-defined presence of static elements. The definition of micro details is between analytical and softened neutrality, which somewhat polishes the sibilance of aggressive IEMs like the Final A8000s, and also densifies the timbre a bit. I wouldn’t say that the noise floor is 100% black, because the silence between instruments is a little vibrant, but it’s not far from it, especially when using IEMs and headsets not intensely sensitive to output impedance.

The precision is very high with the M15, even in fast and complex passages the rendering is very articulate and defined in the separation of its attack. But the M15 has a slightly rounded sound at each end, so the sub-bass will be a little more difficult to pin down or feel, and the very high frequencies will not be perfectly sculpted.
Being familiar with this ES9281 DAC, I can confirm that the M15 pushes its technical performance to its peak, including its level of resolution, transparency and definition of these micro-details.


One of the most difficult aspects to describe is the dynamic rendering of an audio source, which is often more dependent on its type of amplification than on the decoder itself. Here, I feared that the M15 rendering would be too flat and linear, similar to a THX amp, and thank God, this is not the case at all! We are in the best of worlds with the M15, which balances between attack speed and resolving capacity with a desire for musicality well felt in the heaviness of impact and the reliefs of diversified attack amplitudes. The impact of the notes has weight, the piano does not sound flat. The mid-bass hits hard, with a nicely sculpted roundness. The high frequencies are incisive in the attack and restore as much in their body and harmonic presence. This dynamic doesn’t create much resonance after impact, which is good for bass impact and also midrange control, but a bit less for more airiness and echoing super high-frequency brilliance. .


The spatial presentation is well balanced between width and depth of scene, and also very realistic. It doesn’t sound closed, it’s circular and full, with no presence hole. It’s wide and reasonably deep but won’t enlarge your headphones’ stage unduly. What matters here is that it doesn’t compress the rendering or affect its accuracy, which is fully the case with the M15. The sound imagery is really impressive, without artifice we have a natural separation of the moving sound layers and enough well-defined space between the static instruments. It’s not analytical but naturally revealing, even I would say that the entire sound spectrum is treated in the same way, so no micro high details better separated than the rest accentuating an impression of air and space. As for PRaT (Pace, rhythm and timing), it’s excellent here and proof that we have a mid-range DAC-AMP of high quality and fidelity. The M15 will never muffle or distort excited passages of speedy busy music and deliver sharp timing into full articulation regardless of the attack speed.
The density of timbre is amplified by the longer sustain of the notes than their impact resonance time, so no, the micro separation of each note playing at crazy speeds will not be magnified or shadowed by a mixture of impact resonances.
Attack sustain-release is central to precision, accuracy and attack speed definition. Here, the M15 is not 100% perfect and my SMSL SU-9+SH9 stack is cleaner and more precise in sustaining and detonating sounds. Still, the M15 is superior to all my other DAC-AMPs at this level, including the Tri TK2 and Xduoo Link2 Bal, which have more harmonic distortion and impasto when I play the frenzied jazz rock album ”Dodovoodoo” by Elephant9.



VS XDUOO Link2 Bal (dual cs43131+independent Opamp-270mw@32ohmbal-160$)

There are two big acoustic differences that strike the informed listener when comparing these two excellent DAC-AMPs, these are the wider stage width and height of the Xduoo as well as its warmer resolution and less clear and precise than the M15. Immediately, the technical performances of the M15 seem higher, both in the control, the synchronicity, the speed and precision of the counterpoints of the attacks and the cleanliness of resolution in the macro and microscopic sense. The M15 is more neutral, less colored by warmer, looser and boosted bass. This may make its dynamics seem weaker and limited in amplitude power, but this is not the case if we compare the treble rendering which is more pushed and extended, delivering and extracting micro details with greater ease, this which is evident in fast and complex passages of music, where the Xduoo will show some limitation in terms of saturation and distortion, both higher than the M15. Xduoo has a warmer, analogous and fleshy tonality, with thicker and opaque sound layers, it favors relief more than the texture of the timbre and its transparency than the M15. Its highs shimmer less and get lost more in its fluffy sonic ensemble. M15, without being cold or clinical, delivers less soft and rounder basses in their impact, and a more precise, articulated instrumental separation without adding color. The Xduoo remains a superior DAC-AMP in terms of construction and tactility, having a volume control, a gain switch and even UAC 1.0 and 2.0 selection switch, but above all a chassis that seems extremely durable compared to the pretty body of the M15 which has a glass certainly interesting for the eyes but worrying for the durability. In the end, the M15 offers a more neutral and detailed tone with superior technical performance and slightly less powerfull amplification to the Xduoo Link2 Bal.

VS TRI TK2 (dual ES9038q2m+A\B amp-1250mw@32ohm-280$)

What strikes the listener in the first place is how the spatiality is wider, grand and open as well as the dynamics more corpulent and heavy in impact. The general resolution is more subdued and not as clean with the TK2, without being dark, only less precise and cut in its separation and less clear in the definition of each instrument. The M15 is more neutral and analytical, with a thinner and more textured timbre, better transparency but a more closed and condensed scene. The bass is more colorful with the TK2, warmer and boosted with a less defined but more resonant hit, which tends to make the transition with the mids more veiled and organic. Here, the M15 does not force the bass overflow into the mids and keeps the separation clear while delivering a more energy-focused and resonantly controlled strike. The mids seem a bit flatter and set back with the M15, but more centered and less diffuse in their separation. High frequencies are drier, clearer and more textured with the M15, delivering more energetic and fully rendered percussion. The TK2 is about 5 times bigger and heavier than the M15, it is not really portable and its gain is triggered when you pass a certain volume level, I would have preferred a switch like the M15. Technically speaking, I would conclude that the M15 is superior due to a darker noise floor, higher resolution, more precise instrument separation as well as a more controlled and less diffuse attack, however I tend to prefer the warmer, natural and open tone of the TK2 because the instruments have more body and a wider and creamier projection, but my conclusion in terms of musicality might be different with less aggressive IEMs than the A8000.


VS Xduoo Poke II (dual CS43198 dac-700mw-390$)

Another excellent DAC-AMP using current amplification, but this time with an ES9281C saber DAC. Also, without battery and with supposedly lower amplification force although more energetic in its dynamics. Here, the M15 delivers meatier, vibrant and warm bass with more pronounced impact heaviness. The resolution is almost identical, although less finicky in the micro-definition, favoring a roundness of tone denser than the Poke II. In terms of precision and separation, the Poke is an iota superior because it is clearer and cleaner with a more restrained attack in its echo. The M15 has a spatial rendering that has more relief and sculpture of presence, giving a more holographic and open effect in height and width. The spatiality of the Poke is deeper with more static instrumental positioning, more defined and focused in the high frequencies. The flatter, more clinical rendering of the Poke tends to be less immersive and encompassing for the listener than the M15, which despite a technical performance of high resolution and a bit lower micro-details, delivers a more natural, physical and tonally accurate musicality.



With the FINAL A8000

These exceptional intras are my reference no1 because the presence of all the frequencies is fleshy, dynamic, clear and precise, nothing is behind and despite a few points in the bass, midrange and high, the balance is intended to be energetically neutral. . With an overly aggressive DAC-AMP, the A8000s can scream a bit and the M15 doesn’t cause this while preserving their high resolution and dynamic energy. The first thing I notice is that the basses are more textured and transparent, preserving their heaviness of impact without boosting their resonance. The sub-bass is not pushed back or attenuated and vibrates naturally without taking over the mids with a surplus of presence. The mids are less prone to sibilance than with a FIIO KA3, but don’t gain much body, it remains fairly centered with high clarity and good separation. It’s not compressed but not very open either. The highs gain in fullness of timbre but not in brilliance or resonance In terms of spatiality, it gains in depth while maintaining an average width and height. The instrumental separation is not negatively impacted but does not gain space. Let’s say that the A8000s remain faithful to their deep nature with the M15, without added color, their tone or timbre is not boosted any further, and their technical performance is accentuated in controlling their extremely fast attack. Still, I would have preferred a little more addition in terms of dynamics and also the presence of bass.

With UM Mext

These two seem to be made to go together, the presentation here is so beautifully balanced, corpulent in dynamics and highly resolute. MEXT basses gain in roundness, texture and immediacy of impact. The mids are superbly resolved, clear, transparent without grain but nuanced in texture, here it’s open and frontal, it seems that the bone conduction driver appreciates the amplification while running, it’s clean, wide of stage and natural , truly breathtaking. And what about the highs, again a similar treatment, but less thin and shiny than with some other dongles like the Tempotec E44. The amount of sound information is infinite but transmitted delicately, and once again, the completely black background accentuates the cleanliness of the space, improving the resolving complexity and instrumental separation as well as the depth of the scene. Truly, if you’ve owned MEXTs and are looking for the perfect dongle to do them justice, the Questyle M15 is its soul mate.


I would have thought that this pairing would be perfect, but it’s not exactly that…here we have clearer and more aggressive Arias, with more emphasis on texture and dry tone. The bass, which was already lacking a bit of well-felt punch, does not gain any advantage, although the kick drum has more texture and a gripping presence, and it seems that the sub-bass extends and vibrates less too. The mids are less organic, leaner and drier, with a flatter presence and less open projection. The highs gain in texture and grip, suddenly the electric guitar sounds surprisingly good, with a rich and transparent distortion, more bite in the attack, something that was often missing with other dongles such as Tri TK2, Xduoo Link2 Bal, but what is strange is that the body remains thin, so the guitar lines do not have this heaviness and immediacy of presence.

With the FINAL E5000

Here we have IEMs known to be difficult to drive correctly and I will be short because indeed the E5000 creates a disaster with the M15. I was expecting a little compressed sound but here it’s distortion problems with the bass that ruin the listening. But not only. The transducer really doesn’t seem to like the current type of amplification and I don’t know how to explain this. The entire dynamic becomes distorted at the slightest increase in diversified amplitude mixing different frequency spectra. At low volumes, this won’t be as problematic, but the E5000s will sound flat in dynamics, compressed in image and too emphatic in the highs. If you plan to use M15 for the Final E5000, I strongly advise against it.

With the Audiosense T800

Let’s start by saying that the T800s are sensitive to the amplification impedance and the M15 is not the lowest on this side (more or less 1ohm). Fortunately, this does not result in extreme distortion, although sometimes present at high volume, especially with high gain. At low gain, the rendering is tonally linear and dynamically energetic. The bass is more textured and less boomy and resonant, which accentuates the clarity of the T800s and makes them more balanced neutral because the highs are not amplified. The vocals are less prompt to sibilance and a little less open in width. I would say that the T800 loses cleanliness and analytical clarity in more complex passages, which does not happen with a lower impedance source like the Xduoo X20 or Ibasso DX90 (0.1ohm).



In the last years, i’ve been spoil with alot of great sounding dongles, ranging from 20$ to 500$. Lot of them were redundant too and not that much of a big sound upgrade in the 20 or more I try or own. So, I learn exceptional sounding DAC-AMP are rare when it come to plain sound quality.

Here, with the M15 we are in mid-costy territory, so my expectation were very high. To conclude that it offer high sound value mean it’s able to compete with pricier DAP or DAC-AMP in sound quality, and thanks to the magic of current mode amplification as well as good DAC implementation of Questyle, this DAC-AMP deliver a sound quality that fit or even surpass it’s price tag. It’s literally end game dongle for everything but perhaps end game amping power.

The M15 might be the only ”reference” ultra portable DAC-AMP out there, in the sens that it deliver an high fidelity neutral sound with heavy dynamic heft and natural yet crisp resolution. This high end dongle know how to sign and dance, it have enough power output for majority of IEM and Headphones while not being hungry for your phone battery life, and hey, it show you it’s geeky soul under the glass of it’s body too!

Highly recommended!


PS: I want to thanks Questyle for sending me this review unit and answering all my questions too. It was a very pleasant communication, very generous, transparent and informative. I'm not affiliated to this nice company and share my 100% independant honnest audio impressions as always.

You can buy the Questyle M15 for 250$ from this official seller:

For more honnest and diversify audio reviews, give a look to my No Borders Audiophile website
Last edited:
@klaus2325 why wouldn't a current amplified dongle be a great pair with low impedance planars? Also if it's the dream pairing with the MEXT, the Rai Pentas are essentially that. If stated OI is <1Ohm its unit variation for the money but still entirely negligible with regard to down sloping response or BA loading.
Thanlks for your kind answers. I´ve totally misunderstood something. Sorry for my "silly" question
@klaus2325 i didnt try those iem-hp but indeed, M15 can be imprevisible in some rare case like with E5000 i write about in this review. I wouldn't suggest M15 for very capricious or sensitive IEM nor for very power hungrry headphones as an end game source. Especially low sensitivity db one.


100+ Head-Fier
Questyle M15 USB DAC/Amplifier Review
Pros: Overall Clarity, Resolution and Authority,
Very Balanced & Natural Sound Profile,
Both 4.4mm Balanced & 3.5mm Single Ended Outputs,
Ultra Clean Output that is Ideal for Sensitive IEM’s,
Powerful Output for power hungry Headphones,
MQA & Native DSD Support up to DSD256,
Stylish Design & Premium Build Quality
Cons: No Physical Buttons for Volume Adjustment,
No Protective Case or Lightning Cable included to the Package (The Leather Case is available for FREE for a limited Time)

Questyle M15 Ultra Portable USB DAC/Amplifier Review



Questyle Audio is a Chinese company that is specialized in research of high-tech lossless audio system such like Desktop Amplifiers (CMA800/CMA800R), DAC/Amplifiers (CMA Twelve, CMA Fifteen, CMA 400i), Wireless Audio Systems, Portable DAC’s (M12) and Audio Players (QPM, QP2R). Questyle has won over 20 international awards since 2015, such as CES Innovation Award, iF Industrial Design Award, and VGP Lifestyle Award, while Foxconn Technology Group is a strategic partner of the company.

The Questyle M15 that I will now review for you is the company’s flagship ultra portable USB DAC/Amplifier that features a ESS ES9281AC DAC Chip, TOREX High-Efficiency Power Management Unit and both 3.5mm Single Ended and 4.4mm Balanced Analog outputs. Moreover, the M15 contains two of Questyle’s patented CMA (Current Mode Amplification) SiP modules, for a total of four CMA AMP engines to driver both Sensitive IEM’s and demanding headphones as well.



I would like to thank Questyle for providing me the M15 Ultra Portable USB DAC/Amplifier as review sample. I am not affiliated with Questyle beyond this review and these words reflect my true and unaltered opinions about the product!

Price & Availability:

The actual MSRP price of the Questyle M15 USB DAC/Amplifier is 249.00 US$. More information’s can be found under the link below;

Package and Accessories:

The Questyle M15 came in a relative small rectangular back cardboard box with a premium look and feel that sports some product related brandings o the top and specifications at the bottom.


Inside the box are the following contents & accessories;

  • 1 x Questyle M15 Ultra Portable USB DAC/Amplifier
  • 1 x USB Type-C to USB Type-C Low Profile Cable
  • 1 x USB Type-A to USB Type-C Low Profile Cable
  • 1 x Print Material (Instruction Manual & Guarantee Card)


The M15 has a premium looking leather case available in 3 different colour options that is sold separately for 30.00 US$. The good news is that you can get now for FREE for as Launch Gift for a limited time (till 15th of May).




Design & Build Quality:

The Questyle M15 is an amazing looking USB DAC/Amplifier that offers a unique visual experience with its CNC machined aluminium housing with a transparent top cover, which feels very premium and robust when you hold it in your hands.


The M15 is an Ultra Portable USB DAC/Amplifier with dimension of approx. 61.8[L] X 27.2[W] X 12[D]mm without the low profile cables that are included inside the package.


The main body that is made from CNC Machined Aluminium alloy material is in black colour and shows a rectangular shape with slightly rounded edges.


At the left surface of the M15 is the Low & High hardware switch that I do prefer over software controlled gain options.


At the right surface of the device is the “M15 Mobile Lossless DAC with Headphone Amplifier” branding.


On the top of the M15 is a transparent top cover that makes it possible to see the PCB layout with all the hardware components like the ESS ES9281AC DAC Chip, TOREX Power Management Unit, SiP Current Mode Amplification modules, 4.4mm Balanced and 3.5mm Single Ended output and more, which offer visually attractive experience.


Here are also two LED light indicators, one is dedicated for the gain status (red & green) and the other one is the Data Indicator that gives information about the actual payed format.


On the top of the device are both the 3.5mm Single Ended (with CTIA support for headphones featuring phone calls) and the 4.4mm Balanced (TRRRS “Pentaconn”) headphone outputs that do offer a tight and sturdy connection.


The rear surface of the M15 ultra-portable USB DAC/Amplifier features the Questyle logo/branding.


On the top of the device is the USB Type-C DATA port that is dedicated for the digital data transfer.


The overall build quality of the Questyle M15 and the cables is of high quality that fulfils my expectations from an audio gear at this price level.


Technical Specifications:

  • DAC chip : ESS ES9281AC
  • Frequency Response : ±0.1dB (20Hz-20kHz)
  • THD+N : 0.0003%
  • SNR : -130dB
  • Output power : 3.5mm: 11.97mW @300Ω, 4.4mm: 22.60mW @ 300Ω
  • PCM : up to 384kHz (16/24/32Bit)
  • DSD : up to Native DSD256 (1Bit 11.2MHz)
  • Dimension : 61.8[L] x 27.2[W] x12[D] mm


Hardware & Software Features:

The Questyle M15 is an Ultra-Portable USB DAC/Amplifier that offers some impressive hardware specs such like the ESS ES9281AC DAC Chip, TOREX High-Efficiency Power Management Unit and two of Questyle’s patented CMA (Current Mode Amplification) SiP modules.

A) DAC (Digital to Analog Converter):

The M15 features ESS Technologies ES9281AC flagship DAC Chip, which is a feature rich 32bit 2-Channel Digital to Analog Converter that utilizes the critical acclaimed ESS patented HyperStream II architecture. The device offers an impressive SNR (Signal to Noise Ratio) of -130dB and a decent THD+N (Total Harmonic Distortion) of only 0.0003%.

The Questyle M15 support sampling rates from 16, 24, 32Bit, 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384kHz and up to Native DSD 256 (1Bit 11.2MHz).

The LED Indicator that is visible under the transparent front panel of the M15 gives information’s about the data status, which are list below;

  • Green: Sample rate is 48kHz or less.
  • Red: Hi-RES lossless files up to PCM 88.2kHz~384 kHz & Native DSD64~DSD256.
  • Magenta: The M15 is performing the final unfold of an MQA Core stream.


B) Connectivity:

Inside the box are two low profile USB cables, one USB Type-C to USB Type-C and one Type-A to USB Type-C cable to connect the M15 to your Digital Music source.

Devices offers a plug and play function that supports Android 5.0 and above, Apple iOS devices such like iPhone and iPad, Windows PC’s with Win10 1803 and above, and Apple computer with MAC OS.


C) Amplification & Background Noise:

The Questyle M15 is a very powerful device especially for an Ultra-Portable USB DAC/Amplifier thanks to the use of its patented SiP modules, for a total of four CMA AMP engines. This quadruple drive amplification circuitry gives enough out power to drive even high demanding planar headphones such like the HiFiMAN Sundara or SIVGA P-II.


Questyle’s Current Mode Amplifiers are characterized by their small footprint, low voltage operation, and minimal power consumption. Current Mode amplification offers also a low impedance (according to Questyle that is not listed on their specs), a bandwidth up to 1MHz and a Total Harmonic Distortion of 0.0003%.

Here are some Technical specs about the output power of the Questyle M15:

  • 3.5mm: RL=300Ω, Po=11.97mW, Vout (Max) = 1.895Vrms, THD+N=0.00045%
  • 4.4mm: RL=300Ω, Po=22.60mW, Vout (Max) = 2.624Vrms, THD+N=0.00057%
What I really like and immediately noticed on my first listen to the M15 was the ultra-clean and dark background that allows you to hear and to discover even the smallest micro details, which is quite impressive for a device with such a small footprint.


D) Power Consumption & Overheating Performance:

The Questyle M15 is equipped with the TOREX High-Efficiency Power Management Unit to archive a relative low power consumption to increase the battery life of your source, which was quite decent compared to other USB DAC/Amplifiers that I have used before, especially with such a powerful amplification capability.

What I also found quite impressive is the that the Questyle M15 doesn’t overheats after long listening periods, even while powering some of my high demanding full sized open-back planar headphones such like HiFiMAN Sundara or SIVGA P-II.

Equipment’s used for this review:

  • DAC/Amplifiers : Questyle M15, Cayin RU6, Shanling UA5
  • USB Source : Samsung Galaxy Note10 Plus, Asus TUF FX505DU
  • IEM’s : Meze Audio RAI Penta, Campfire Audio ARA, Kinera URD
  • Headphones : SIVGA P-II, HiFiMAN Edition XS, HiFiMAN Sunadra


Albums & tracks used for this review:

  • Adele – My Little Love (Spotify)
  • Randy Crawford – On Day I Will Fly Away (Flac 16bit/44.1kHz)
  • Hayley Westenra – Odyssey Album (Dezzer HiFi)
  • Dionne Warwick – Walk On By (Flac 16bit/44.1kHz)
  • Sarah McLachlan – Angel (Flac 24bit/48kHz)
  • Sertap Erener – Aşk (Flac 16bit/44.1kHz)
  • Sonya Yoncheva – (Giuseppe Verdi) II Trovatore, ActI (Flac 24bit/44kHz)
  • Edith Piaf – Non Je Ne Regrette Rien (Flac 16bit/44.1kHz)
  • Diana Krall – So Wonderful (DSF)
  • Aretha Franklin – I Say A Little Payer (Flac 24bit/96kHz)
  • David Bowie – Heroes (Flac 24bit/192kHz)
  • Elton John – Rocket Man ((Flac 24bit/96kHz)
  • Barry White – Just The Way You Are (Flac 24bit/48kHz)
  • Isaac Hayes – Walk On By (Flac 16bit/44.1kHz)
  • Sting – Englishman in New York – (Flac 24bit/48kHz)
  • Eric Clapton – Wonderful Tonight (Flac 24bit/96kHz)
  • B.B. King – Riding With The King (Tidal Hi-Fi)
  • Dave Gahan – Kingdom (Tidal Hi-Fi)
  • U2 – Sunday Bloody Sunday (Flac 16bit/44.1kHz)
  • Bro Safari, UFO! – Drama (Deezer HiFi)
  • Armin Van Buuren – Vini Vici (Flac 16bit/44.1kHz)
  • Really Slow Motion – Deadwood (Deezer HiFi)
  • Massive Attack – Angel (Flac 24bit/192kHz)
  • Lorde – Royal (Flac 24bit/48kHz)
  • Toutant – Rebirth (Deezer HiFi)
  • Gogo Penguin – Raven (Flac 24bit/192kHz)
  • Portishead – It Could Be Sweet (Spotify)
  • Charly Antolini – Duwadjuwandadu (Flac 24bit/192kHz)
  • Michael Jackson – Billie Jean (Flac 24bit/192kHz)
  • Ferit Odman – Look, Stop & Listen (Flac 24bit/192kHz)
  • Chopin – Nocturn No. 20 In C-Sharp Minor (Flac 16bit/44.1kHz)
  • Fazıl Say – Nazım Oratoryosu (Live) (Flac 16bit/44.1kHz)
  • Vivaldi – Le QuarttroStagioni “The Four Season” (Deezer HiFi)
  • Otto Liebert& Luna Negra – The River (Flac 24bit/192kHz)
  • Lunatic Soul – The Passage (Flac 16bit/44.1kHz)
  • Deftones – My Own Summer (Shove it) (Flac 16bit/44.1kHz)
  • Photek – The Hiden Camera (Spotify)
  • Muse – Hysteria (Flac 24bit/48kHz)
  • Metallica – Sad but True (Flac 24bit/96kHz)
  • Opeth – Windowpane (Flac 16bit/44.1kHz)
  • Megadeth – Sweating Bullets (Tidal Hi-Fi)
  • Rush – YYZ (Flac 16bit/44.1kHz)
  • Rush – Leave That Thing Alone (Flac 16bit/44.1kHz)
  • Slayer – Angel of Death (Spotify)
  • Liquid Tension Experiment 2 – Acid Rain (Spotify)
  • Yosi Horikawa – Bubbles (Spotify)

The Sound:

The Questyle M15 immediately impressed me with is very natural, pretty organic, balanced and highly transparent overall sound presentation, which also benefits from an ultra-clean & pitch-black background that creates an atmosphere where you can hear even the smallest micro details.

This review has been written after a burn-in period of approx. 80 Hours. I have paired the Questyle M15 with sources like the Samsung Galaxy Note10 Plus and the Asus TUF FX505DU PC. My sound impressions below are mainly based on my experiences over the 4.4mm Balanced output paired with the Campfire Audio ARA, Kinera URD, Meze Audio RAI Penta IEM’s and HiFiMAN Edition XS and SIVGA P-II headphones.



The Questyle M15 offers a very natural and balanced bass response along with a decent grade of technical performance. The general bass character of the M15 can be described as highly controlled and quite detailed, from the subbass up to the midbass area.

The subbass region of the M15 reaches pretty low and offers a good sense of rumble and control paired with IEM’s like the Kinera URD or Meze Audio RAI Penta when I do listen to songs like Bro Safari, UFO’s “Drama“, Lorde’s “Royals” or Massive Attack’s “Angel”.

The midbass region is one of the highlights of this ultra-portable DAC/Amplifier that is reproduced with great sense of impact, clarity and authority when I do listen to complex passages Charly Antolini’s “Duwadjuwandadu” or Gogo Penguin’s “Raven”.

Instruments from cellos to bass guitars do have a good level of weight and fullness, while snare and kick drums are represented in a pretty tight and impactful manner when I have listen to the Questyle M15 with high-end In-Ear Monitors like the Campfire Audio ARA and Meze RAI Penta.



The Questyle M15 shows a very natural, liquid and highly transparent midrange presentation with decent sense of airiness and headroom for instruments and vocals. The general tonality of the midrange is a tad warmer than neutral and pretty organic, which is one of the highlights of this small USB DAC/Amplifier.

The lower midrange of the Questyle M15 offers a pretty good sense of body and depth when I do listen to male vocals like Barry White, Elton John, Dave Gahan or David Bowie or to instruments like acoustic guitars, violas or trumpets. The upper midrange region is another highlight of the Questyle M15 that is reproduced in a quite detailed, dynamic yet controlled manner. Female vocals from Adel to Sarah McLachlan, Edith Piaf to Randy Crawford do sound lively, fluid and emotional, especially when I pair it with IEM’s like the Kinera URD, Meze Audio RAI Penta and HiFiMAN Edition XS headphone.

Instruments on the other hand do have a pretty natural timbre and are shown in highly detailed and well extending manner that surpassed my expectation from such a small and well-priced product. What also surprised me was the sense authority when I have listen to guitar solos with high level of distortion such like Megadeth’s “Sweating Bullets”, Slayer’s “Angel of Deaths” or to Rush’s “Leave That Thing Alone”.



The treble range of the Questyle M15 is fluid, highly controlled and detailed. It offers a decent sense of presence and brilliance when I do listen to instruments and soprano voices. The transitions in moment when instruments do play with high level of distortion are reproduced in a quite controlled manner with all IEM’s and headphones that I have listen to it, which is quite surprising for a devices that is equipped with a ESS Sabre DAC. This shows how well the sound engineers have implemented an ESS Saber DAC that sounds both detailed yet controlled in this area.

The lower treble range of the M15 adds to the overall presentation a decent level of clarity, while the extension is pretty successful while listen to instruments like snare drums or cymbals and soprano voices like Sertap Erener and Sonya Yoncheva.

The upper treble region is able to produce a pretty good level of airiness and sparkle when I do listen to instruments such like pianos, hi-hats or cymbals, especially when paired with the Campfire Audio ARA, SIVGA P-II and HiFiMAN Editions XS.

The overall control, extension and detail retrieval of the Questyle M15 is simply stunning, while the intensity and quantity in this area is not too much or too low, which makes it to a very versatile source.


Soundstage & Imaging:

The Questyle M15 has a fairly spacious and airy soundstage atmosphere that is suitable for a precise placement and separation of instruments and vocals. The soundstage of the M15 shows an efficient level of depth and wideness that is not spectacular but sufficient for such an Ultra-Portable USB DAC/Amplifier device.


Questyle M15 versus Cayin RU6:

The Cayin RU6 is one of the popular Ultra-Portable USB DAC/Amplifiers on the market that gained attention with its discrete R-2R DAC circuit design and powerful output capabilities for its size.

When it comes to the build quality, I can say that both products do offer a premium look and feel. The Cayin RU6 is slightly thicker and longer with dimension of 65×25.4×13.7mm, while the Questyle M15 is a bit slimmer and a bit wider with about 61.8×27.2x12mm. The RU6 has a small OLED screen that gives information about the sampling rate, volume, etc. and comes with physical hardware buttons that are dedicated for volume and mode selection. The M15 on the other hand has no screen or buttons for volume control, but comes with LED light indicators that do give information’s about the sampling and gain status, and is also equipped with a Low/High gain switch that the RU6 not has.


Both devices do offer both 4.4mm Balanced and 3.5mm Single ended outputs. The Cayin RU6 is equipped with its own 24-bit R-2R DAC design, while the Questyle M15 features the ESS ES9281AC DAC Chip. Both are capable to decode Native DSD up to DSD256 and PCM 24 bit/384kHz, while the M15 supports also MQA. The RU6 and the M15 are able to driver full sized open-back planar headphones such like the SIVGA P-II or HiFiMAN Sundara/Edition XS, while the Questyle M15 seems to be even more powerful than the Cayin RU6 especially on high gain. What I don’t like about the analog outputs of the RU6 is that there is an audible background noise, while the M15 is death silent. The EMI shielding of the RU6 seems not to be the best, since it has picks up some interference from my Samsung Galaxy Note 10 Plus, when I put them side by side.


As for the sound, I can say that both devices offer different flavours that can be preferred to each other. The Cayin RU6 shows a slightly warmer tonality that is close to the classical analog sound signature, while the difference is not very high. The Questyle M15 seems to be slightly more neutral in tonality, but has also a pretty organic timbre.

Both the subbass and the midbass region of the Cayin RU6 do show slightly more depth and intensity compared to those of the Questyle M15. However, the M15 has the upper hand in terms when it comes to the clarity, resolution and sense of authority in the lower frequency register.

The midrange of the Cayin RU6 has a pretty warm tonality and highly musical character that I really enjoy. The Questyle M15 on the other hand shows a slightly more natural, neutral and somewhat organic timbre when I do listen to both vocals and instruments. The M15 offers a higher sense of transparency and airiness in this area. The lower midrange of the RU6 shows a bit more body and depth, while the M15 has the slightly edge when it comes to the clarity and resolution in this register.

The upper midrange and the treble region of the Questyle M15 sounds slightly more highlighted and energetic/dynamic compared to those of the Cayin RU6, without to be overly sharp or sibilant. The treble region of both devices sounds in general pretty controlled, while the M15 has the slightly edge when it comes to the level of resolution, extension and separation that was quite audible when I do listen to instruments like cymbals or hi-hats.

The soundstage of both the Cayin RU6 and the Questyle M15 shows an efficient level of depth and wideness, while the M15 has the slightly edge when it comes to the depth and airiness of the stage. Another advantage of the M15 is its pitch black background that makes it easier to hear micro details.

Questyle M15 versus Shanling UA5:

The Shanling UA5 is the company’s new flagship USB DAC/Amplifier that I have reviewed recently. It is equipped with a build-in Lithium Battery that is part of its “Hybrid Power Mode” to reduce the power consumption of the source and to give the components a stabile energy source in order to increase the sound performance.

Both the Shanling UA5 is a premium looking device with a high build quality same like the Questyle M15. The UA5 is relative longer and thicker with dimension of 68x27x13.5mm (versus 61.8×27.2x12mm) while both are equal in terms of wideness. The UA5 comes with a small OLED screen that gives information about the gain mode, volume and sampling rate. Moreover it has a multifunctional wheel for volume adjustment and navigation that the M15 not has.

The UA5 is a pretty powerful device that offers both 4.4mm Balanced and 3.5mm Single Ended outputs like the M15. However the M15 is again more powerful compared to the UA5, especially at high gain, while both devices do offer a quite similar in terms of background noise performance, which is a tad cleaner on the M15. The Shanling UA5 is equipped with 2x ESS Sabre ES9038Q2M DAC chips, which do offer PCM decoding up to 32 Bit/768kHz & Native DSD up to DSD512, while the PCM and Native DSD decoding of the Questyle M15 is limited with PCM 32bit/384kHz and DSD256.


The Shanling UA5 shows a slightly brighter tonality and more energetic overall sound signature, while the Questyle M15 shows tad more neutral tonality and more balanced presentation from the lows to the highs.

The lower frequency region of the M15 sounds more dynamic, fast and has also the upper hand when comes to authority in complex bass passages such like Gogo Penguin’s “Raven” or Charly Antolini’s “Duwadjuwandadu”. Both devices do offer a clean and detailed sub- & midbass presentation, while the M15 is the source with the more fluid and natural character in this area.

The midrange of the Shanling UA5 shows a slightly brighter tonality and a more energetic overall presentation, while Questyle has managed do create a more organic and liquid midrange character from an ESS DAC chip. Both the UA5 and the M15 do offer a pretty transparent and airy midrange atmosphere with decent level dynamics and resolutions that can compete with full sized Android DAP’s with double or even triple the price. The lower midrange of the Questyle M15 shows a bit more body that was audible when I have listen to acoustic guitars and violas, while both do offer a fairly similar performance in terms of resolution in this area.

The upper midrange of the Shanling UA5 is slightly more highlighted yet a bit dry and sharp when I do listen to female voices or to instruments like clarinets, violins or pianos. The Questyle M15 on the other hand sounds pretty controlled and natural in this area, which makes is more compatible with different earphones/headphones and enjoyable for longer listening periods.

The treble range of the Shanling UA5 is slightly more pronounced and energetic compared to those of the Questyle M15 that shows a more balanced and natural presentation in this area. The lower treble region of both devices is detailed, extends pretty well and offers a decent sense of clarity and definition. The upper treble register of the Shanling UA5 is a bit more highlighted and detailed, while the M15 offers a higher level of authority and separation.

The soundstage of the Shanling UA5 is slightly more expansive, while the Questyle M15 shows a better performance when it comes to the depth of the stage.



I have tested many Ultra-Portable USB DAC/Amplifiers so that I can easily say that the Questyle M15 is one of the best available on the market. It immediately impressed me with its unique design, premium appearance and with its very natural, highly detailed and mature sound presentation. Moreover, it comes with both 4.4mm Balanced and 3.5mm Single Ended outputs that do offer plenty of power for demanding headphones and an ultra-clean background for sensitive In-Ear Monitors. All this features are packed in to a small device that can compete with full sized DAP’s that do cost twice or even triple the price that M15 has.

Thank you for the Read!​

Wow yet another reviewer working for Questyle. These reviews are starting to make me ill.
@Pirastro Sorry mate, I don't work for Questyle or any other Brand. You have just read my subjective opinions about a product that I have got for review. Cheers :beerchug:


500+ Head-Fier
Questyle M15 - Hi-Fi Sound on the Go
Pros: -
- Superbly well balanced neutral and natural sound
- Reference grade technical prowess
- Amazing driving power
- Highly versatile and adaptable to any partners
- Native iOS support
Cons: -
- I wish there was an independent volume adjuster
- Slightly larger in size compared to competitors

Questyle M15​

Review Date: 30 April 2022

Quad amplification engines
Flagship-grade ESS Sabre ES9281AC
Dual Headphone Output Ports(3.5mm Single-Ended+4.4mm balanced)
Two-level gain switch
LED indicators for gain and active bitrate
Low power consumption TOREX power chip
Technical Specs:-
Decoding Parameters: PCM 32-Bit/384kHz, DSD256
Output Interface: 3.5mm single-ended, 4.4mm balanced
Output Power(3.5mm): 11.97mW @ 300Ω, Vout (Max): 1.895Vrms
Output Power(4.4mm): 22.60mW @ 300Ω, Vout (Max): 2.624Vrms
Frequency Response: 20Hz-20kHz±0.1dB
THD+N: 0.0003%
Dimensions: 61.8×27.2x12mm

Test Equipment

IEMs and Earbuds:

  • Etymotic ER4SR (Single BA, 45 Ohm, 96db Sensitivity)
  • Shure KSE1500 (Single Electrostatic 200V, KSA1200 Energizer)
  • Kinera Idun Golden (3BA + 1DD Hybrid, 32 Ohm, 112db Sensitivity)
  • Tripowin HBB Olina (Single DD, 32 Ohm, 110db Sensitivity)
  • VE Asura 3.0 FE SLQ (Single DD, 155 Ohm)
  • VE Monk GONE SPC (Single DD, 32 Ohm)
  • BuduBuds V1 (Single DD, 32 Ohm)
  • FOSTEX T40RP MK3 (Magnetic Planar, 50 Ohm, 91db Sensitivity)
  • Beyerdynamic DT880 (Dynamic Drivers, 600 Ohm, 96db Sensitivity)
  • Windows 10, Foobar 2000 (USB 3.0 Power)
  • LG V50 ThinQ (UAPP USB Exclusive Mode, Bitperfect)
  • Sony Xperia X Compact (UAPP USB Exclusive Mode, Bitperfect)
  • HiBy Music Player App (USB Exclusive Mode)



At the time of my review, my M15 has been upgraded from FW Build 9086 to Build 9277 which can be downloaded directly from Questyle here:

Questyle M15 marked the progression and evolution introduced with M12, the only Current Mode amplification Dongles to exist now. It is no secret that among over 120 Dongles I owned, the M12 ranks the highest in my book for ESS Sabre unit. I even prefer it more over Apogee Groove and the slew of Hidizs S9 Pro, E1DA 9038 or REIYIN DA-Plus – all of which prime examples of properly tuned ESS Sabre units.

When M15 was released, gleefully I took the opportunity head first to have it delivered to my doorsteps. Full of anticipations and excitement. I know Questyle has great tuning principle and this is a known fact among many audio enthusiasts. Let’s see how does M15 fares in the real world shall we?

PS: As noted above, my M15 has undergone a Firmware update and the entirety of my review are based on it – post FW update.

Build, Functions, Usability​


M15 is a huge Dongle, in fact I daresay it is 3x the size of M12. It is probably the 3rd largest Dongle I ever owned. Apogee Groove being the largest then followed by CEntrance DACport HD. By current standards, M15 is one hell of a solid device construction wise. The traditional rectangular design being simple as it is functional.

Most prominent feature would be the glass faceplate on one side. The glass window would allow us to savor looking at the beautifully crafted internals. Clearly showing generous real estate of components. As I said earlier, M15 is large. The rationale behind this, Questyle opted to go purist route on M15. They forgo the need to downsize in favor of innovation, to ensure that M15 will have all the bells and whistles of a top of the line performer.
Feature wise, despite the size, M15 offers equally simple stuffs like imbedded led lights that can be seen through the glass window. One for power/resolution and another one for High/Low gain. On one side, there’s user selectable hardware switch for gain selection.

However, M15 does not offer any sort of volume adjusters on the Dongle itself. I must admit that I wished it would have include some sort of independent volume adjusters. What I have learned so far, independent volume adjustment does have big role in fine tuning listening loudness. As observed with the likes of Cayin RU6, DACport HD and Lotoo PAW S2 – all of which comes with super refined volume adjusters, the ability to fine tune volume levels has help to elevate music listening greatly – at least in the manner of how I normally use the Dongles – set the volume at Max on the host and let the DAC/Amp regulate the output. Perhaps Questyle can consider this in earnest in upcoming Dongle line-ups.

As for the volume adjustment itself on the host side, like most other Dongles without independent/dedicated adjusters, M15 depends largely on the volume steps resolution of the source. So in order to have fine adjustment, it is necessary to use HiBy Music App (Software Volume Mode) or UAPP Volume Steps. But at least I can tell natively M15 does offer “less jumpy” gain between levels as observed with some other devices.

While M12 came with just 3.5mm SE, M15 stepped up to the current standards of including a 4.4mm BAL Pentaconn port. Balanced circuitry that offers discrete power each channels (L/R) instead of shared GND. This has allowed them to push the power output higher and will work great with power hungry partners.

In alignment with what was already introduced with M12, M15 also offers the latest iteration of Questyle Current Mode amplification. I honestly don’t know much about this technology, so I would not dwell too much talking on it. But what I do know, the Current Mode amp stage of both M12 and M15 plays huge role in shaping up the sonic characteristics they offer.

As with most other Dongles nowadays, M15 comes with female USB C interface for the data link. This will allow for swapping of cables to suit the needs. Included in the stock package, M15 comes with both USB C and iOS Lightning cables. This effectively means that M15 is among the few that has been designed and built from scratch with versatile compatibility to iOS.

Despite being a “larger than normal” Dongle, M15 appeared to be adequately efficient with power draw to the host. With my Sony Xperia X Compact (Android 8, 2700 mAH Battery), M15 was able to clock 5-6 hours of continuous play – driving Tripowin Olina at low gain, USB Exclusive mode UAPP. This is pretty much on par to the competitions like Lotoo PAW S2 and Cayin RU6. Only xDuoo Link2 BAL and HiBy FC5 scored better at almost 7 hours.

Most impressive, M15 is probably the best Dongle DAC/Amp with heat management. Despite the larger size, M15 was able to stay relatively cool even on prolonged sessions.

Sound Impressions​


Questyle M15 is a wonderfully balanced DAC/Amp. From the moment I plugged it in with my Etymotic ER4SR, I was already mesmerized with fluid, crisp, smooth and highly resolving output that does not exhibit any coloration in any frequencies. It is admirably organic and refined sounding. Despite being an ESS Sabre based DAC, there’s absolutely no hint of Pinna Glare or unnatural edgy brightness that is notoriously evident with most ESS devices. The signature of Questyle tuning, it is super clean with immaculate resolved notes and tones – while at the same time managed to avoid the pitfalls of sounding sterile and dry. If I am to turn back the clock over a year ago, when I first tried the older M12, I remember the output was already amazingly clean and pristine – however I did mentioned that M12 (with the old Firmware) has some tendency to emit some dryness. Questyle fixed that for good with M12 later version FW. What I am hearing now from M15, an evolution of that immaculate sound. Something that is exceedingly technical yet musical.

Perhaps if I am to nitpick, on a very personal level I normally prefer a bit more of analogue touch to the output, M15 seems to be not as analogue sounding when compared to CEntrance DACport HD, Ovidius B1 or Cayin RU6. M15 is more aligned with the Hi-Fi sound approach which is favored by L&P W2, HiBy FC5, Colorfly CDA M1 and REIYIN DA-Plus – which means among them all, I can easily say that M15 is the BEST of the crop with that Hi-Fi approach. That effortless dynamics and transients making it such a pleasure to listen to, the overall theme being crispy smooth, resolving and detailed.

On dynamic range, M15 is assuredly a stellar performer. The extensions on both ends nothing short of impressive. What I am hearing from my regular favorites of Shure KSE1500, Etymotic ER4SR and Fostex T40RP MK3 revealed how rich the extensions are. Highly detailed on macro and micro levels. Sub Bass being rich and dense, Treble being sparkly with proper texture, Mids being wholesome and engaging – and keeping it neutral, uncolored while at it. Never a moment I felt that any of the frequency range being emphasized beyond what is realistic.

Technically, M15 is an absolute beast. Just like the predecessor of M12, M15 carried on with that trajectory with some of the very best technical performances I have heard so far. Being critical, perhaps the only caveat that I can point out would be the average sized soundstage which I wished could be a bit wider. In this regard, I would say that the likes of xDuoo Link2 BAL, THX Onyx and DACport HD offers the widest soundstage still. M15 on the other hand is pretty much similar to Cayin RU6 and Lotoo PAW S2, it has breadth of space, depth respectfully spacious but just slightly short on absolute width.

What M15 does offer in spades, reference level of resolution, imaging, speed, details and separation. M15 is a device that will please even the most demanding need for technical indulgence for listening to highly complex music. The better the recording and mastering, the better it gets. For example, with highly complex Jazz composition, I was able to appreciate even the most subtle of nuances – presented with crisp imaging and cleanly defined layers. In fact M15 performed miracles with my favorite duo of Kinera Idun Golden and Tripowin Olina – elevating those two IEMs technically to TOTL level of performances, no joke!.

As I always mentioned, the hallmark of a great DAC/Amp – their ability to synergize with anything. And M15 is one such devices. Be it my super hard to drive Beyerdynamic DT880 600 Ohm and Fostex T40RP MK3, open back VE/BuduBuds earbuds, highly sensitive hybrid IEMs, even legitimate 200v Electrostatic of Shure KSE1500, M15 does it all with such guile and finesse. That’s how a true neutral DAC/Amp should behave – it does not show any specific preferences to what sound curves the paired partners have. It just works

Driving Power​


Questyle M15 is a 2.62 Vrms rated dongle (4.4mm BAL). Despite not being a 4 Vrms device, M15 does have tons of power at its disposal. This is similar to the performances of Ovidius B1, Hidizs S9 Pro and Creative SXFi, the other 2 Vrms devices that offer tons of power to even handle super stubborn magnetic planars.

For my own usage, M15 performed spectacularly to drive Beyerdynamic DT880 600 Ohm with ease. On HiBy Music App USB Exclusive mode, M15 only needed 16/32 volume for proper listening loudness. On my PC it was at 40/100 max (any higher and it would be just too loud for my comfort). Simply put, the sort of performance offered by M15 in this scenario really cemented my belief that I don’t need a dedicated desktop DAC/Amp stack combo. Everything about the sound simply being wholesome and satisfying. No hint of micro jitters or distortion. It’s all about fluid harmonics end to end. I am not hearing any loss of micro details. About the only thing missing, perhaps absolute headroom sense, like 2% less headroom as compare to the output as heard from my iFi ZEN Stack of ZEN DAC V2 + ZEN Can. That 2% is totally negligible. The same can be said for the magnetic planar of Fostex T40RP MK3, one of the most stubborn planar headphones out there now – no sweat for M15.

On the other hand, despite all that power, M15 has also shown amazing synergy with super sensitive and easy to drive stuffs. I am getting super clean output from my Tripowin Olina and Kinera Idun Golden. Pitch black background even on the most silent of passages. This is consistent even on High Gain mode.

Volume Difference (With Etymotic ER4SR, HiBy Music App, USB Exclusive Mode)
SE 3.5mm = 12/32 (Low Gain)
BAL 4.4mm = 9/32 (Low Gain)

I am happy that both 3.5mm and 4.4mm ports shared identical sound quality. The difference only the absolute limit 4.4mm can go which is up to 600 Ohms. However for anything under 155 Ohm the 3.5mm will work as great as the 4.4mm side. Once volume loudness matched, I can’t hear any difference at all. This is simply amazing because I have heard many (if not all) Dongles being slightly inferior on the 3.5mm side, but M15 does not neglect this element. In comparison, the likes of Luxury & Precision W2 and Lotoo PAW S1 practically treated the 3.5mm port like a 2nd class subject.


Questyle M15. All things considered, I am confident that M15 being one of the very few releases for 2022 that can claim 5 stars rating. Sound wise, M15 offered practically everything that I like about sonic performances. The balance of neutral organic timbre, totally uncolored and devoid of any unpleasant edginess commonly associated with ESS Sabre DACs.

M15 biggest strength being superbly versatile and effortlessly fluid in projecting Hi-Fi sound in a compact form factor. Yes it is 3x bigger than M12, but the size is well justified for a truly complete package when it comes to delivering sound quality. If I must be critical, then my only wish list would be an independent volume adjuster – had that been included, M15 would have assuredly been perfect.

Simply put, Questyle M15 has set a very high standard for how a great modern Dongle DAC/Amp should sound. It is amazingly well crafted to be competently technical as it is musical. Mesmerizing every time I listen to it.


Best Pairing: Anything up to 600 Ohms​

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@gtx1690ti Yes absolutely. Especially on low gain mode, M15 is very silent and forgiving to highly sensitive IEMs and hybrid. And it doesn't really matter what sound curve your IEMs are, neutral DAC/Amp will always pair well with them
Hello @OspreyAndy, would you recommend M15 or S2 to be a better pairing with Sennheiser IE600.
On another note, I would like to confess that I am a big fan of your Dongle rankings and consider you to be the crinacle of dongle DACs.
Really appreciate your work :)
@DrFever Thanks!. For IE600 it will synergize better with M15 especially if you prefer precision and technicalities. But if you want a bit more of velvety smoothness then S2, yeah I know I am not really helping here lol. But then I love both of them for their native attributes