BenKatz

100+ Head-Fier
LDAC Excellence + USB prowess
Pros: - best-in-class, refined sound quality and tuning
- excellent LDAC stability, even at max bitrate (990 kb/s)
- lightweight + compact size, in-built metal clasp
- very solid app with "transparency" mode and parametric EQ
- heaps of power for it's class, price and size
- excellent built quality (made in KOREA)
- great mic-quality for calls
- great battery life
Cons: - buttons a bit flimsy/easy to press + weird location
- no display or button indicators
- not water-proof in any way
- although the packaging is nice and unique, a more premium unbox experience would go a long way for brand-awareness
- OTA software update has some issues
- no way to configure buttons and no way to access smartphone Assistant (Google Assistant/Siri/etc)
After reading a few impressions, and using Fiio BTR5 for more than half a year (and being so unhappy with it that I relegated it to car use, in the meantime going through some other DACs) - I decided to order the Qudelix 5k and try it - particularly after reading that it was a Sony partner when implementing LDAC (this was interesting to me considering the HORRIBLE LDAC/BT performance on the BTR5)

20210402_113101.JPG


In order to keep this this review concise, I'm going to simply expand each Pro and Con and elaborate:

PROS:

1) Best-in-class, refined sound quality and tuning

When doing a review, it's obviously crucial to have a reference or competitor to compare. In this case, it's none other than the BTR5. I got the Fiio more than half a year ago, and although I was excited initially due to the reviews and design - I grew to almost hate it really quickly - and i've been through 2 of them already. The BIGGEST issue I had with the BTR5 was the LDAC stability. When moving more than 4-5 meters from the source, and/or when going to the gym/biking/for a jog, and keeping my smartphone in one pocket and the BTR5 in another, it would simply be unusable - constant, constant cutouts. I've tried numerous suggestions and "fixes" online, I even exchanged it thinking it was a lemon - no luck, when it comes to BT stability in many conditions, the BTR5's BT implementation is in itself a LEMON. Another 2 things I never liked about it were the sound quality and heft.
The sound always felt blunt, with minimal tuning. It doesn't have the "refined" sound one would expect from a decent DAC, even tough it was rather neutral.
The design was also quite bad - in order to clip it on a shirt, you had to use the case, which was horrible since it already made a very heavy device for it's category even heavier and bulkier. And the disappointment was aggravated by the fact that the in-built mic sounded pretty bad, much worse than an in-line mic on a cable.

Enter QUDELIX 5K. I'm happy to report that in the past week since I got it, I've had 0 (ZERO) dropouts, even when using it on the bike or at the gym - either in a separate pocket than the smartphone or on the t-shirt collar. Besides that - the sound REALLY impressed me. Just to note - I have NOT played around or modified any settings, eq, etc - I just left it standard (DAC- Performance mode - not 100% clear what that means but it's the best setting).
To compare to the BTR5 - it sound MUCH more refined, wider soundstage, better extension. I was so unhappy initially with the BTR5 that I reverted to using the jack on my phone (Sony Xperia 1 mark2 - it has dual Cirrus Logic DACs + DSEE Ultimate sound upscaling AI tech) - though the phone had less power (which didn't matter for me since I've used 2 very sensitive IEMs - Campfire Audio Polaris 2 and Dorado 2020), the sound from the phone had more heft in the lower registries and better separation (which amazed me). I ended up getting a Dragonfly Cobalt for PC use, which was closer (but a bit better) than the phone output.
As far as the QUDELIX 5k - I can say without a doubt that it sound MUCH better than the BTR5 - not a BIT but MUCH. Also, compared to my Xperia 1 II output, it also sounds wider with more headroom, and it's VERY VERY close to the Dragonfly Cobalt, which costs 2.5 times more (the Cobalt has slightly better top-end extension and separation, you have to REALLY listen to it to realise). Suffice to say, I've already sold the COBALT since I have no use for it anymore.

This is valid for both LDAC sound quality, and USB-DAC sound quality, vs the BTR5. I know some people pointed out in some reviews that on the spec sheet, the BTR5 has some dedicated USB controller. How does that help? I don't know, there's no point for a "spec" since it doesn't translate in actual performance. Same story with measurements. I turst what I hear - the BTR5 with it's advanced USB Controller does NOT sound (at all) as good and refined as the Qudelix 5K when used as a USB DAC.

20210402_113154.JPG


2) Excellent LDAC stability, even at max bitrate (990 kb/s)

Not much to expand more here - as stated at 1), it is absolutely excellent when paired with my Sony Xperia 1 II

3) Lightweight + compact size, in-built metal clasp

This is a HUGE plus, especially over the BTR5. I can now easily clamp it to my t-shirt collar when doing sports activities, and this is all I really needed (as stated before, the BTR5 with the clasp-case was huge and very heavy). This way I can use whatever cable I want, even experiment with balanced, since I'm not forced to use a cable with in-built mic mmcx cable to be able to take calls with the BTR5 - and then when I "jailed" the BTR5 in the car stereo, in order to take calls with my phone (since Campfire Audio headphones, besides the Comet, don't come with a mic), I had to buy a new cable with in-built mic.

DSC_0067.JPG


4) Very solid app with "transparency" mode and parametric EQ

There is not comparison with the "basic" Fiio app here. The app si excellent and lets you adjust a lot of things. 2 very crucial features, which you cannot find on many (or any?) other such companion apps for BT DACs are the Parametric EQ (I don't need it at all, but some might, it can even transform certain headphones that have issues), and the Transparency mode, AKA "Mic Pass-Thru" (which is amazing). Basically this is like any transparency mode that you can find on most NC headphones (like Sony, Bose or Apple). It lets you adjust how much sound to let through, and is VERY useful when going for a run, on the bike, or even in airports when listening for announcements (this is complemented by the fact that it's light-weight with in-built clasp and can easily be clamped to the t-shirt collar or such, even when doing sports). One small criticism here is that it doesn't seem to work if there's no music playing through the headphones - this is a small minus, and Qudelix should add the feature to always keep the transparency enabled, even if no music is playing - it can be very helpful.

Screenshot_20210402-114039.png


5) Heaps of power for it's class, price and size

Not much to comment here - just check the specs. It has huge gusts of power (more than the BTR5). If you have smth hard to drive, this is your device. Not me though, my IEMs are quite sensitive and low-ohm.

6) Excellent Built Quality

Same here, not much to comment - even though it's plastic + metal clasp, the built quality is very SOLID. The BTR5 is also very well built.



7) Great mic quality

This is a huge + compared to the BTR5. The voice simply comes across as much cleaner and clearer, and you can even adjust it in the app. I can finally buy better cables (balanced also) and experiment without losing the call functionality like I did with the Fiio due to it's bad BT connection and mediocre MIC quality.

20210402_113329.JPG


8) Great battery life

Simple - I get 1.5-2h more than the BTR5 on Performance + LDAC. that's around 7 hours vs 5.5 (BTR5). This is a straight forward PLUS.

CONS:

1) Buttons a bit flimsy/easy to press + weird location

It is what it is - even though the design is "cute" and the opposite red and blue led for each button looks nice (like a mini Blade Runner hover-police car), they are basically rocker buttons, and they don't have a lot of resistance when pressing - accidental presses are quite easy unfortunately. The location is also not great (on the top corners of the device...why??)

2) No display or button indicators

I personally don't care much for a display since I don't really need to look at it (and eats a bit of battery), but this is simply a feature that is absent on the Qudelix, but is present on the BTR5. Also, it has no button indicators at all.

3) Not water-proof in any way

This is not really a FAIR minus (no other device has IPX rating either, in this category, at least as far as I know) - but considering one of my use cases is doing sports with the Qudelix attached to the t-shirt collar, it gets touched by sweat from time to time, and sweat-proof rating would be a huge addition for reliability and longevity.

4) Although the packaging is nice and unique, a more premium unbox experience would go a long way for brand-awareness

I mean...look at it :)) Check more online photos. Yes, there is some innovation there as it's sort of a origami-type technique to make the box so small, it doesn't really scream "cheap" - but having a much nicer box with some extras inside is what many people enjoy when getting a new device and unboxing it, it makes the experience memorable, and it's a very useful marketing tool for companies that want to build customer retention.
It can be argued that this is cost-cutting decision, and it can be justified, considering the device cost is in-line with the Chinese counterparts, but this is built in Korea (higher production costs). But considering the advantages, I think asking for 10% usd extra and shipping it with a premium box would go a long way and would help Qudelix more in the long-run.

5) OTA software update has some issues

This is something that needs to be fixed URGENTLY by Qudelix. Basically, in order to not have a FAILED update, you need to keep the screen open and the app in the foreground during the entire process. Switching out of the app or letting the phone go into idle mode (screen off) instantly freezes the update process, and you need to either repair or reinstall the app. Frustrating. On the other hand, it's not a minus vs it's direct competitior, the BTR5 - that one has no OTA update (as of yet) and needs to be updated in a very "oldschool" manner using a PC, and that also means you need to check the support page on the FIIO website from time to time to even KNOW if there's a new update. The Qudelix app instantly notifies you when there's an update.

6) No way to configure buttons and no way to access smartphone Assistant (Google Assistant/Siri/etc)

I consider this a big functionality omission by Qudelix. Almost every other product in this category (BTR5 included) has a way to map a button to be used as the Assistant activation in order to easily call someone when doing other activities (for example). NO such option on the Qudelix, you can't even re-map the buttons. I really hope this can be added in a future SW update - QUDELIX - PLEASE ADD ASSISTANT BUTTON MAPPING OPTION! 10X!

And that pretty much wraps my review. For reference, this is the gear I've used in this comparison/review process:

Sources: Laptop (USB) and Sony Xperia 1 mark2 (LDAC BT)
DACs: Qudelix 5K (duh!), Fiio BTR5, Audioquest Dragonfly Cobalt (sold)
Headphones: Campfire Audio Dorado 2020 (main), Campfire Audio Polaris 2 (for sale), Sony XBA-N1AP (sold)

Attachments

  • Screenshot_20210402-114103.png
    Screenshot_20210402-114103.png
    425.2 KB · Views: 0
  • 20210402_113501.JPG
    20210402_113501.JPG
    4.6 MB · Views: 0
Last edited:
Lowtech Trevor
Lowtech Trevor
Thanks for the review! Question: it looks like you can set the ambient level to be active only during voice calls and not while music is playing. Is that correct?
szore
szore
Excellent review. My Q5K is out for delivery! I'm coming from the BTR5...

MatusSVK

100+ Head-Fier
Qudelix 5K-As good as they get right now
Pros: -Very good kind quality for a BT receiver
-Quite tiny
-Solid build
-Stacked App
-Good power output
-Well thoughout controls
-Flawless BT connection
-Good battery life
Cons: -The build is mainly plastic
-The shirt clip is non-removable
-Unexciting design language
-Buttons can be accidentally pressed
-Spec-wise it's near identical to it's competitors
Introduction
Qudelix is a new American company, set up by the former lead engineer of the now famous Earstudio ES100. The Qudelix 5K is a new Bluetooth DAC amp, featuring the new CSR8675 BT receiver, one of its main advantages over its competitors, such as the Fiio BTR5 and Shanling UP4. Otherwise, the three feature the same dual ES9218P DACs, balanced and unbalanced ports and a USB-C port, as well as app support. All this can be had for $109.

Package
The Q5k comes in a very simple cardboard box, which includes the BT device, USB-C to USB-C and a USB-C to USB-C cable, as well as some paperwork. The unboxiing experience is simple, but gets the job done 6/10.
20201220_153900.jpg


Built

The Q5k is made of mainly dark, hard plastic, with only the clip and skrews being made of metal. It feels very solid, but at the same time quite light, lighter than it looks. The whole device is tiny, smaller than the relatively big UP4 and still smaller (by volume) than the BTR5. Considering they have nearly the same specs, this is really quite impressive.

The one downside to the build is that it is made of plastic, as a result it simply doesn't feel as premium as the glass and metal sandwiches of the BTR5 and UP4. I personally wouldn't mind a slightly higher weight, in return for a more premium feeling build, but I do understand the decision. Also, the one aspect that is made of metal, the clip, is non-removable. To me, it feels very solid, like the rest of the build, with good strength, but it could become a problem to replace if broken. Overall, although maybe the not most premium feeling device, it is solid and I have little worries in its long-term durability, therefore it gets a 8/10.

Controls
The device features 4 buttons in total, two on each side. The ones on the right feature a blue light underneath, while the ones on the left have a red light. The light intensity, or when or even if the lights turn on, can be customised to your preference in the app, and so can the functions of the buttons. You can choose which buttons turn on/off the device, skip and go back on tracks and turn up/down the volume, essentially everything you would want. As a result, the controls are very comprehensive and warrant a 8/10 rating, the only real downside again being the plastic build, which include the buttons, as a result the controls are not as tactile as the ones on the BTR5.
info_3.jpg


Bluetooth Connection
Not much to say here. The device features Bluetooth 5.0 with the newest Bluetooth processor, which supports practically all Bluetooth codecs available. The connection occurs automatically once turned on, and is rock solid once connected, with no hiccups. I've had absolutely to issues with its Bluetooth connection 10/10

Sound
As a declaimer, I'am not very experienced in the world of external DACs, therefore my view might be a bit limited. Also, the following sound impressions have been made exclusively using LDAC and a USB connection only.

The Q5k features a 3.5mm unbalanced and a 2.5mm balanced port. They feature a 2.0 Vrms and 4.0 Vrms power output respectively, meaning it is powerful enough to drive just about any IEM on the balanced port, the same as the BTR5 and UP4.

The sound coming out of the device is of very good quality, especially for a Bluetooth device. It is quite neutral, from bass to treble, with just a slight lift on both ends. It's neither warm nor cold and note thickness is neutral as well. There are multiple minor improvements in sound quality, overall improving the SQ a great deal from a simple smartphone.

To start of with, the bass gets a very slight lift, but the main improvement is in speed and impact, which improve quite significantly. The mids remain quite uncolored and experience probably the least change from the overall sound signature. The treble also features a slight lift in quantity, improving resolving power and adding a but more spice to the sound of your IEM, although not by much. Lastly, soundstage improves quite substantially in all dimensions. Width and depth improve and so does imaging and layering, leading to a more detailed and more engaging soundscape. All these little changes lead to a greatly improved sound, compared to a smartphone. There is further improvement to the sound in all aspects, athough very minor, when connected through the USB port. Overall, this is as good as a Bluetooth receiver will sound at this price 10/10. I've also experienced to hiss through the device, although I haven't used it with a pair of particularly sensitive IEMs.

App
This is really the main advantage of the Qudelix compared to its competitors. The app is quite simply fantastic. It has all of the features a user would ever want, including an excellent parametric equalizer. The app is very well done, with a great user interface, and includes things like a battery graph, volume controls, Bluetooth codec selection DAC/AMP mode, DAC filters, output power and even days under warranty remaing. It is miles ahead of what Fiio or Shanling offer and still gets regular updates.

I have to specially mention the PEQ. It is really good quite simply. Its a 10 band one, which can be either parametric or geometric. It changes the sound very effectively, with little effect on overall sound quality. There are now custom presets that can be used by the user, on top of some pre-made ones. All in all, this might be the biggest reason to get the Qudelix over the Fiio or Shanling. The app gets a straight 10/10 for this.
Screenshot_20201220-150528_Qudelix.jpg

Battery
The battery life is actually surprisingly good for such a small device, claiming actually to be better than both the UP4 and BTR5. It has a claimed 6-20 hour battery life (depending on volume and power mode. It usually lasts me about 2 weeks of usage with about 1-2 hours of listening per day. It is charged through the USB-C port, and can be used while charging, which is a really nice feature to have. The app also features a battery graph, which is a nice touch.
Screenshot_20201220-151459_Qudelix.jpg

Conclusion
To sum up, the Qudelix 5k is a fantastic device. There's very little wrong with it. It has a fabulous app, great sound, good built and very good battery life. Compared to the Shanling UP4 and Fiio BTR5, it's smaller, with better Bluetooth connection. To me, this is a absolute no-brainer, if you are in the market for a BT DAC amp. The only real downside for me is just how similar all these BT devices are, but I believe the app on the Qudelix really makes it worth the extra 10-20$ over the latter two. This is as good of a small BT portable amp you can get.

Thank you for reading all the way down here : ) This my one of my first review ever and would highly value any feedback given and I hope that you have enjoyed this review. Also, if any company also enjoyed this review, and would wish to send me some gear to review, I would be delighted to do so.


  • Like
Reactions: Tano

Zelda

Headphoneus Supremus
Pros: Compact design
Separated buttons for playback and volume
Sound quality as wireless source
Excellent volume control, up to 120 steps
Very good battery time
Decent build quality
Cons: Buttons can be too sensitive
Layout needs some time to get used to
REVIEW – Qudelix 5K – Bluetooth Amp-DAC

5k (1).jpg


Website – Qudelix
Specifications

info (1).jpg


info (2).jpg


Price: U$D 109.

Shipping costs will vary depending on the country. It is also available from Amazon US.

Many thanks to Qudelix for the 5K review unit.


5k (2).jpg

Design

The 5K has a compact design with a very rectangular shape. It is made entirely of plastic, main body and buttons, with the exception of the attached fixed clip which is made of metal. The plastic material can make it look plain but it is well built and seems solid enough. While an aluminum body could be tougher and more durable, for the better wireless signal the option is either plastic or glass. Glass may be nicer but more fragile and easier to catch fingertips. The clip is strong enough, though I’d preferred it was removable. There is no official case for the 5K but Dignis had already made one.

5k (3).jpg

The layout is pretty simple, well distributed but not the most comfortable. There is a rocker button on each side of the device. Their defaults functions are described on the box, but can be changed from the app settings. I found them logical enough so didn’t mind anyway.

5k (4).jpg

The right side buttons work for power on/off, playback, Bluetooth pairing and managing calls. The left button is for volume control. Below are the functions of each one by default.

5k (5).jpg

5k (6).jpg

Having separated controls for volume and playback is very comfortable. You can press and hold the volume and smoothly adjust it thanks to the up to 120 volume steps and slight increase of 0.5db each. The Fiio BTR3K and BTR5 are more annoying as the same rocker button works for volume and skipping tracks, where you need to make multiple single clicks to change the volume and hold to skip tracks.

There are LED lights under each button that (by default) turn on whenever the buttons are pressed or when pairing the device; blue to the right and red to the left.

info (3).jpg


The buttons are too sensitive and they are placed exactly opposite to each other, so when pressing one side the other’s side button can be easily pressed. It is not very annoying but needs some time to get used to.

At the upper side are the two audio outputs, single 3.5mm and balanced 2.5mm. To the opposite side there is the USB Type-C socket for charging or for wired DAC use.

5k (7).jpg

There is an issue to note regarding the audio outputs. When using the 2.5mm and then switching to another headphone on the 3.5mm port, the sound will be unbalanced and distorted. The only way to fix it that I found is to turn off the 5K and reconnect it again. This may not happen all of the time but most of it. I’m not sure if it is a particular problem on the unit I received or not, though it seems to be because the device tries to continue to output as in balanced sound mode and does not change back to single-ended.


Software

Like other portable Bluetooth amp/dac devices, Qudelix also offer an application for Android and iOS devices. I don’t own any modern iOS, but with Android it is limited to be used with only 8.0 and higher versions. Well, it was released in 2020 and it is supposed to be used mainly with smartphones so they expect that everyone should own an updated one. Moreover, if you want the best wireless audio quality you’d want a phone that supports LDAC or at least AptX/HD.

The app shows all the technical info about the 5K device, battery time and performance, firmware details and even remaining warranty period. There are various screens that can be accessed by the corresponding icons at the bottom bar, each for a different hardware or software configuration. There is a short description of the many features on each screen. Both the source device and 5K volume can be controlled by the app, as well as changing the buttons’ functions, volume limit, codec, output power and sound quality performance.

A more interesting and probably the most useful feature should be the equalization section. Good news is that all the EQ options can work over BT, including LDAC, and also when used as wired USB DAC. All the configuration and EQ are saved into the flash memory of the 5K so will remain the same when connected to other devices. The EQ is offered in two flavors: Graphic (GEQ) and Parametric (PEQ). On the Graphic EQ are some included presets and 20 extra Custom slots that can be user defined. The Parametric EQ is always much more complex and requires some knowledge and time to use but allows a more precise customization of the sound.

The app performance may depend on the device, and from a Samsung Galaxy Tab with updated Android 8, the app is very stable. Also Qudelix keep releasing updates with high frequency (compared to other companies), and the app is already fairly usable since the recent release of the 5K.

app (1).jpg
app (2).jpgapp (3).jpgapp (4).jpgapp (5).jpgapp (6).jpgapp (7).jpgapp (8).jpgapp (9).jpgapp (10).jpgapp (11).jpgapp (12).jpgapp (13).jpg

Bluetooth quality

The main purpose for the 5K is to be used as a wireless audio receiver, and Qudelix suggest it is better used with smartphones (Android 8+ or iOS) than with other Bluetooth supporting devices (PC, non-Android audio players, etc.). In fact, the wireless connectivity turns out to be better when used from Android 8+ devices and even more when the app is working. With the Galaxy Tab connectivity is very stable and the wireless range is very good even with a couple of walls in the way, even with LDAC codec on.

Battery

The battery performance is very good on the 5K. It is advertised as able to play up to 20 hours, but of course it will depend on the BT codec, volume level, audio output and audio performance set on the app. Using IEMs and earbuds it easily plays to more than 10h in higher performance and 2.5mm balanced, so the numbers seem rather accurate, and anyway is the best battery time among other BT receivers.

5k (8).jpg

5k (9).jpg

Sound Impressions

The Qudelix 5K follows similar sound characteristics to most of the compact portable sources I’ve tried at this price range. Regardless of their purpose or inner hardware components, from audio players, wired or wireless USB amp/DAC, they tend to present a more or less neutral and uncolored sound. There are always differences in their final tuning when compared to each other, but none of them put much coloration to the sound or go overboard sounding too warm or too bright.

Sound quality on the 5K is very positive. Without using any EQ it is clear, very neutral and clean, presenting no hiss with the more picky sensitive IEMs I could try. The very wide volume range of 120 steps allows a perfectly accurate and comfortable listening with very low impedance IEMs, usually multi-BA or hybrids, and can also get loud enough with more demanding sets without showing major signs of distortion. It can drive IEMs like the final E5000, B1 and Dita Twins with more than decent power, and also 120ohm earbuds, on-ear headphones like SM P55 Vento, and if you insist, the new iBasso SR2 will sound decent enough for such a small device; not my choice, though.

Despite the very neutral signal, there is a very slight sense of warmth to sound that gives a more natural texture. While the low-end is nothing elevated, when using the DK-3001 Pro and Dita Fidelity which are very neutral their bass they gain more body and little more solid impact and decay, and even the 3-BA Fibae 3 sounds less bass light. The midrange is very clear, not particularly airy or open, but less congested or artificial than with the BTR3K/M5 or Shanling M0. The treble quality is particularly good on the 5K. Detailed, clean and fairly natural and a bit smooth, and very good for a BT device. A bit surprising from what I’d expected from a Sabre DAC at this price and compared to the other Sabre based sources where the treble has more brightness and is less forgiving. There are still the usual limitations in terms of average soundstage and extension, but it is acceptable for the price and especially being wireless quality, and the more natural timbre and tonality the 5K presents as a sub $200 source makes up for its limitations.

While the single output works with only one DAC chip, switching to the balanced output takes advantage of the dual Sabre DAC. When changing to the balanced option there is a jump in output power that is clearly audible in the louder volume of around 8dB which translates into ~15 steps in the 5K device volume scale. The overall sound presentation remains unchanged but it is a bit better, more open, with more air and sense of space, especially noticed in the treble response. Not a must but worth using if you already have the setup for it and don’t mind the faster battery drain.

cqtek

500+ Head-Fier
The Magic Clip
Pros: Above all, sound quality.
- Balanced 4V RMS output, in addition to the classic 3.5mm.
- APP control, totally comprehensive, robust, yet simple and very well explained, from the screens themselves.
- Very low weight.
- Clip.
- Easy to use.
- Reduced size.
- Logical operation of the buttons.
- Graphic and parametric equalizer, 10 bands.
- Very high sound quality via Bluetooth.
- Huge amount of configuration options.
- Battery life.
Cons: USB DAC limited to 24-bit/96kHz, does not play DSD
- No ASIO drivers.
- Cables are rigid.
- 3.5mm output limited to single DAC use.
- No case to protect it during transport.
Introduction

Qudelix, as highlighted on its website, is an audio systems engineering company, based in Seoul, Korea. They are also a technical partner of Sony LDAC™. They have developed the LDAC solution for the Qualcomm QCC512X platform, which is one of the best chips for audio playback via Bluetooth. This platform, besides offering the best quality codec for Bluetooth audio, has an ultra low power consumption. On the other hand, it has a powerful DSP, capable of maintaining a high bitrate during transmission, in a safer way and for longer. As a result of this effort, Qudelix provides such LDAC codec solution to other brands and/or headphone manufacturers.

All this technical capacity has resulted in one of the most interesting devices on the portable Hi-End market, which combines the best Bluetooth option, with an excellent Dual DAC/AMP by SABRE (ES9218P) and a high output power. This is the Qudelix-5K: a small Bluetooth receiver of very high quality and a DAC/AMP. It can be used as a sound card, connected to a PC or laptop. It can also be connected, via Bluetooth, to a Smartphone or DAP, to be used as a Bluetooth receiver and headphone amplifier. Finally, it can also be connected, via USB-C, to a Smartphone or DAP, to be used as an amplifier. It even has a high-sensitivity microphone as a Bluetooth communication solution.

It has 3.5mm (80mW to 32Ω) and balanced 2.5mm (240mW to 32Ω) outputs.

Another great advantage of this small device (it only weighs 25g) is that it can be governed, completely, by way of an attractive APP, which can be downloaded from the official Google and Apple shops:

https://play.google.com/store/apps/details?id=com.qudelix.qudelix&hl=en_US

https://apps.apple.com/kr/app/qudelix/id1515641059?l=en

It is very easy to use and is capable of getting the most out of the 5K, controlling the volume, output, codecs used, power supplied, sound quality... it even has a graphic and parametric equalizer, 10 bands, which works, even if the source is Bluetooth.

In the present review, I'm going to go through all the details of this versatile and very complete product.

Qudelix-5K 01_resize.jpgQudelix-5K 02_resize.jpg

Disclaimer

I want to thank Qudelix and especially the support staff for giving me the opportunity to try this product.
I also want to clarify that I have no relationship with Qudelix, beyond the information they have provided me, so I could make this humble review.

Specifications

  • Maximum output power 3.5mm Unbalanced: 2.0V RMS (80mW per channel)
  • Maximum output power 2.5mm balanced output: 4.0V RMS (240mW per channel)
  • SNR (A-weighted): 3.5mm -118dB. 2.5mm -122dB
  • THD+N: 3.5mm 0.004%. 2.5mm 0.002%.
  • Separation: 3.5mm 79dB. 2.5mm 117dB (1kHz/32Ω).
  • Output impedance: <1Ω.
  • Bluetooth: 5.0 Class 2 (25mW 4dBm) up to 10m. 2.4Ghz.
  • Bluetooth chip: Qualcomm QCC5124
  • DAC: Dual ES9218P SABRE HiFi®. The 3.5mm output works in single DAC, only. Dual DAC is only available for 2.5mm output.
  • Bluetooth Codecs: aptX Adaptive, LDAC, AAC, aptX-HD, aptX, SBC
  • Battery life: 6 to 20 hours (500mA Battery)
  • Use as USB DAC: maximum resolution 96KHz/24-bit
  • Double Precision 10 Band Equalizer PEQ/GEQ
  • LDS (Laser Direct Structuring) antenna, high sensitivity and 3 dimensions.
  • Technology used for noise cancellation: Qualcomm® cVc™
  • Microphone: High sensitivity MEMS.
  • Firmware update via Over-the-Air (OTA).
  • Complementary mobile application iOS/Android.

Qudelix-5K 03_resize.jpgQudelix-5K 04_resize.jpg

User Guides

https://drive.google.com/file/d/1Z7sMD4v_8P1zYGW7-hrHvHVJRdm-3bQA
https://drive.google.com/file/d/1LD4-w-bbJv3y0XpQjvOh6iaw2bcp_O61

Qudelix-5K 05_resize.jpgQudelix-5K 06_resize.jpg

Packaging

Surprisingly, the Qudelix-5k comes in a small, unpainted, pure cardboard box. Its dimensions are 91x55x55mm. It is sealed with two transparent stickers, on the top and bottom. On the different sides of the box, there are different notes on the product. On the upper side is the brand name, logo, slogan, where it was manufactured (Korea) and the different guarantee certificates. On the lower side there is an EAN13 code. On the other sides, there are drawings of each side of the product, explaining its basic functions, as a quick guide.

After opening the box, on the upper side, you can see the DAC, wrapped in a bubble bag, located in an area adjusted to its size. If you open it from the bottom, you will find a zip bag containing two black cables. One is a USB-C to USB-C type and the other is a USB to USB-C type. They are all male. The full length, including connectors, of each one is approximately 150mm. And that's it, no instruction manual or warranty card is included. On the other hand, the user's manual and the operation note, can be downloaded through the APP or with the existing links on their website (which I have previously linked). These documents are very complete and excellently explained.

The guarantee is for one year and their condition can be checked through the APP.

The content, as you can see, is the minimum required. The packaging feels like an industrial, rather than a commercial product. However, it does not cease to have its charm. The box and its design, through a single sheet of untreated cardboard, its drawings in black ink and its schematic explanations, give an idea of a different product, where the effort is inside and not in other less superfluous things. In any case, I like very much, that austere, simple but ingenious presentation and so reduced in size.

Qudelix-5K 07_resize.jpgQudelix-5K 08_resize.jpg

Construction and Design

The Qudelix-5K is a small regular parallelepiped, measuring 52.8x26.7x15.6mm. Its weight is 25g. Its body is made of very hard black plastic. It also has an anti-scratch UV coating. It has a dark grey aluminium clip at its base. On it are written, in white ink, the model, where it has been manufactured, as well as the different certifications that it complies with. In a vertical position, on the upper face, the one that is closest to the clamp's ball joint, are the audio outputs, 3.5mm and 2.5mm (balanced), as well as a hole for the microphone. On the opposite side is the USB-C connection. On the left side, there is a button with a double function: if you press on its top, the volume increases. After pressing the lower part, it is lowered. It is translucent and lights up in red with each press. On the left side, there is another button, with the difference that it has a bulge at the top, to make it easier to identify by touch. On this occasion, its light is blue. Pressing the upper part for 3 seconds, you enter Bluetooth pairing mode. Pressing the bottom part, also for 3 seconds, turns it off or on, as appropriate. Finally, at the base of the front panel, you can read "qudelix" in inscribed letters.

Despite the fact that the body is made of plastic, with the exception of the clamp, its high rigidity gives a rather hard feeling. Even, with the paint, it seems that its body is completely metallic.

Its construction is extremely compact, only two screws can be seen on the face where the USB connection is. Although, it is possible to see the slots and joints, these are either very small or are very well assembled and do not offer any sensation of weakness. Despite the simplicity of the form, the device has a very effective and functional design, more than striking or spectacular. Above all, its small size, weight (I repeat, 25g), as well as its efficient ergonomics and ease of use, stand out.

Qudelix-5K 09_resize.jpgQudelix-5K 10_resize.jpg

Connectivity

The 5K has two basic functions:

First, as a Bluetooth receiver/headset amplifier: in this case it will be necessary to connect to a Bluetooth source. The audio codecs used are SBC, AAC, aptX, aptX HD, aptX Adaptive and Sony LDAC™. In this regard, it should be noted that Qudelix, is Sony's LDAC "Official Technical Partner" and has developed the LDAC solution for Qualcomm's QCC512x platform, which is a best-in-class SoC for high-end Bluetooth applications. The QCC512x's ultra-low power consumption and more powerful DSP capability allows application devices to maintain a more secure, high-bit-rate LDAC stream for longer. All this information is explained in detail on the brand's own website. It should be noted, of course, that the 5K is the first LDAC receiver to display the active LDAC bit rate.

Second, as a USB DAC/headphone amplifier: the 5K can be connected, via the built-in USB cables, to a PC, a smartphone or a DAP with a compatible USB-C output. In this connection mode, the 5K supports the following sampling rates: 44.1/48/88.2/96kHz. Using the APP, you can choose a single rate or all of them. The bit depth is 24.

Connected to a PC, no drivers are required. For configuration, e.g. with Foobar2000, it will be necessary to choose the "WASAPI" (push) or (event) output and 24-bit. It can also be used with ASIO4ALL.

When connected to a smartphone, it is necessary to choose, in the playback APP, that the audio output be through the Qudelix-5K.

It should be noted that both connections can be established at the same time. The 5K can be connected to the Smartphone, either via Bluetooth or USB. The audio source can be chosen at any time via the playback APP or the Smartphone itself. When this is chosen, it becomes exclusive.

It can also be connected via Bluetooth, through the Smartphone and connected as a USB DAC to a PC. In this case, the Bluetooth source is the main source and the USB DAC connection is the secondary source. Simply by pausing one source and resuming the other, it is sufficient to switch the audio from each source.

The Qudelix-5K has two audio outputs, one 3.5mm and one 2.5mm balanced. The 3.5mm output offers an output voltage of 1V or 2V, selectable through the APP. Using this output, the 5K works in Single DAC mode.

The 2.5mm output offers 2V or 4V, also selectable through the APP. If this output is used, the 5K offers its best technical virtues, as it uses the Dual DAC configuration.

When the high power output is selected, the volume is not increased, but extended to +6dB, instead of 0dB.

The 5K has two profiles or modes: Standard or Performance. The Standard mode provides the best balance between sound quality and battery consumption. Basically, this mode uses the standard operating clock of the DAC and the standard output bias current. The Performance mode gives priority to sound quality as opposed to battery consumption, which may be shorter. In this case, the DAC clock works in its maximum position and the bias current is also the highest.

If connected as a USB DAC, the mode automatically switches to Performance mode, even if the Standard mode is selected.

Qudelix-5K 11_resize.jpgQudelix-5K 12_resize.jpg

Operativity

The Qudelix-5K is an extremely versatile product. In addition to the above, connected via Bluetooth to the Smartphone, the high-sensitivity MEMS microphone can be used, which is built in. In this way, it is not necessary for the connected headphones to have a microphone. However, by means of the APP, it is possible to select the use of one or the other, including the sensitivity level, if the 5K microphone is used.

The operation of the 5k, is quite simple, it has 4 buttons, grouped one on each side, under a transparent casing. Each of them has an LED: blue for the right side (which also has a protruding mark on the top), red for the left. As a quick summary, their functionalities are:

Upper blue button:
  • Pairing mode (long press 3 seconds)
  • Play/pause (one click).
  • Next song (double click).
  • Answer incoming call (one click)

Lower blue button:
  • On/off (long press 3 seconds).
  • Previous song (double click).

Upper red button:
  • Volume up (+0.5dB)

Lower red button:
  • Volume down (-0.5dB)

To pair the 5K via Bluetooth, simply turn on the device and enter pairing mode. At this point, the red light and the blue light come on alternately to indicate this status. It is recommended that LDAC mode is chosen from the Smartphone, for maximum sound quality.

It is also possible, from the development options, in Android, to select the LDAC bitrate. The 990kbps/909kbps, 660kbps/606kbps, 330kbps/303kbps modes as well as the adaptive bitrate mode are supported and can be used. Even the used bitrate can be displayed from the APP.

The Bluetooth range is up to 10m.

The volume has an option, called "Absolute volume", which allows total control of the volume, both of the source (Smartphone) and of the 5K. This allows for fine adjustment and the best possible sound quality. The sound jumps of the device are measured in 0.5dB, obtaining a very high precision, as well as being simple to operate. The maximum volume is 0dB, but when the high gain is set, the maximum is +6dB, which means doubling the amount of volume.

The 5K, on the other hand, has a high volume protection, which protects the connected headphones, when switching between different audio sources. If the volume differences between them are too great, the system adjusts the volume as a protective measure.

The APP can also be used to limit the maximum volume as well as the volume of each channel.

As is usual with many DACs, it is possible to select between different filters. They are as follows:

  • Linear phase fast roll-off.
  • Linear phase slow roll-off.
  • Minimum phase fast roll-off.
  • Minimum phase slow roll-off.
  • Apodizing fast roll-off type 1.
  • Apodizing fast roll-off type 2.
  • Hybrid fast roll-off.
  • Brick Wall.

They can be chosen from the PPP and there are explanatory charts for each one.

The 5K has a 10-band equalizer. Thanks to the use of the QCC5124, which is the neurological centre of the device, it is possible to use such advanced audio processing. Inside is a 32-bit dual-core KALIMBA DSP, which runs at 120MHz. The use of the equalizer is independent of the source used, whether Bluetooth or USB.

The equalizer can be used parametrically (PEQ) or graphically (GEQ). Its equalisation processing is 64bits, with double precision.

It has a large number of pre-set presets and up to 10 individual presets can be saved. All of them are stored in the device's flash memory.

It should be noted that the current status of the device is also stored in the internal memory and when it is switched on again, the system remembers this status.

The battery of the 5K, is 500mA, from Li-Polymer. Only a current of 200mA is required to charge it, a current which limits the device itself. This means that the entire charge takes 2.5 hours (pure and simple mathematics). The included battery charger can be activated at will, except when the battery charge is less than 20%, in which case it will be activated automatically, provided it is connected to a USB.

Connected as a USB DAC, the device uses 200mA for charging, if enabled, and 300mA for operation.

The power mode can be configured, among 4 options: Do nothing, turn on when connected as USB DAC, turn off when charging or turn on or off depending on whether or not it is connected to the charger. All these options can be chosen from the APP.

The battery life can vary between 6.71 hours (Performance mode, Balanced 4V LDAC 96kHz @990kbps) and 20 hours (Standard mode, Unbalanced 1V AAC 44.1kHz) depending on the tests performed in the laboratory.

As usual, the battery life will depend on each individual use, the volume used, the mode, the gain, the codec used and the transfer rate.

My experience of use, based on 70% connected as a USB DAC with the charger switched off and 30% via Bluetooth or connected to a DAP or Smartphone, via USB-C, is that the battery life is, practically, as the tests promise. After two weeks of daily use (1 to 4 hours a day), I have reached 20% battery life. It's true that the connected headphones have been low impedance IEMS or low or medium impedance earbuds. I have alternated use, both by balanced and unbalanced output, switching between high and low gain. In addition, the 5K can be connected to the PC as a USB DAC and when not in use the battery consumption is minimal.

Finally, from the APP, there is a specific section to monitor the use of the battery.

Qudelix-5K 13_resize.jpgQudelix-5K 14_resize.jpg

APP

As I have already insisted, the use of the Qudelix-5K is extremely simple. And the maturity of the APP makes it very easy to have absolute control of the device, and also provides a lot of information: help, links to manuals, to the forum, technical support, warranty management... It also allows the firmware to be updated, through OTA.

The version of the APP used during the writing of this review has been v1.5 and the firmware v1.3.2.

The APP works very smoothly and I have not detected any hang ups or abnormal functioning.

It has 5 large sections and within each section, there are several sub-sections. In summary, the distribution would be something like this:

Section
Sub sections
DeviceDeviceBattPowerMiscAbout
InputStateCodecUSBMIC
VolumeMainOption
DAC/AMPModeFilter
EqualizerEqualizerOption

In addition to the options, each screen has detailed information about each of them.

Personally, I love the theme with black background used, with the text in a soft white and the options selected in red.

One of the most interesting things about this device is its multifunction: it can be connected to the PC at the same time, via USB, as a DAC and connected to the Smartphone, via Bluetooth. All this, while having complete control, by means of the APP. You can listen to music via the smartphone, pause playback and resume playback on the PC, without having to touch the device or the APP at all.

To go into detail about the functioning of the PPP would be excessive for this review. So I prefer to put screenshots of practically all the screens, grouped in groups of 4 screenshots per image. The text is completely in English.

But I would like to mention some virtues and/or curiosities, related to the PPP and the configuration of the device:

  • The operation of the buttons can be programmed, offering alternatives of use to the pre-set one.
  • You can control the activation of the 5K microphone, as well as its gain level or choose to use the headset microphone.
  • It has a guarantee control, specifying the days remaining until the end of the period.
  • You can choose how the device works, when connected as a USB DAC or to a charger.
  • You can control the volume of the Smartphone, the device and display the Bluetooth codec being used, as well as its bitrate and transfer speed.
  • The equalizer can be used even if the selected source is Bluetooth.

Qudelix-5K-Screenshot-01-04_resize.jpg

Qudelix-5K-Screenshot-05-08_resize.jpg

Qudelix-5K-Screenshot-09-12_resize.jpg

Qudelix-5K-Screenshot-13-16_resize.jpg

Qudelix-5K-Screenshot-17-20_resize.jpg


Measures

All measures have been taken with the Performance option activated. The voltage measurements are RMS.

In the following table the 3.5mm output voltage has been measured (selecting the "Normal" or "High" option) with a digital multimeter, using a sine wave of 100Hz and amplitude 1, in FLAC 870kbps to 96kHz.

3.5mm Output
32Ω
100Ω
240Ω
320Ω
620Ω
No-Load
Normal
1.015V​
1.026V​
1.028V​
1.028V​
1.028V​
1.028V​
High
1.97V​
2.02V​
2.02V​
2.02V​
2.02V​
2.02V​

In the following table the voltage of the 2.5mm balanced output has been measured (selecting the option "Normal" or "High") with a digital multimeter, using a sine wave of 100Hz and amplitude 1, in FLAC 870kbps to 96kHz.

2.5mm Output
32Ω
100Ω
240Ω
320Ω
620Ω
No-Load
Normal
1.86V​
2.04V​
2.04V​
2.04V​
2.04V​
2.04V​
High
3.55V​
4.02V​
4.05V​
4.05V​
4.05V​
4.05V​

It can be seen that, at 32Ω, the output voltage does not reach the maximum. It is possible that at low impedance, the amplifier will reach current saturation. It should be remembered that, in the specifications, the maximum power is:
  • 3.5mm: 80mW.
  • 2.5mm: 240mW.
In order to visualize the pure waves, reproduced by the 5K, I used the oscilloscope.

The 3.5mm output, connected to 32Ω at 0dB volume, offers a slight saturation, at 1.06V.

Max-01-3.5mm-a-32-Ohms-a-0dB_resize.jpg


The 3.5mm output, connected to 32Ω at -0.5dB volume, is unsaturated, at 1V. This means a power of 31.25mW.

Max-02-3.5mm-a-32-Ohms-a-0.5dB_resize.jpg


The 3.5mm output, connected to 32Ω at 6dB volume, offers visible saturation, at 2.07V.

Max-03-3.5mm-a-32-Ohms-a-6dB_resize.jpg


The 3.5mm output, connected to 32Ω at 5dB volume, has no saturation, at 1.85V. This indicates that the power of the unbalanced output is 110mW, higher than the 80mW declared. The current required to obtain this power is 57mA.

Max-04-3.5mm-a-32-Ohms-a-5dB_resize.jpg


The 3.5mm output, connected to 100Ω at 6dB volume, does not present saturation, at 2.1V. The power measured at this point is 44.1mW.

Max-05-3.5mm-a-100-Ohms-a-6dB_resize.jpg


The 2.5mm output, connected to 32Ω at 0dB volume, has a clear saturation, at 1.79V.

Max-06-2.5mm-a-32-Ohms-a-0dB_resize.jpg


The 2.5mm output, connected to 32Ω at -2dB volume, has no saturation, at 1.68V. The power at this point is 88.2mW.

Max-07-2.5mm-a-32-Ohms-a-2dB_resize.jpg


The 2.5mm output connected to 32Ω at 6dB volume, has a clear saturation at 3.22V.

Max-08-2.5mm-a-32-Ohms-a-6dB_resize.jpg


The 2.5mm output, connected to 32Ω at 3dB volume, provides a clean signal, at 2.92V. The power measured at this point is 270mW, which is more than the 240mW declared. The current in this case is 91mA.

Max-09-2.5mm-a-32-Ohms-a-3dB_resize.jpg


The 2.5mm output, connected to 100Ω at 0dB volume, has no saturation, at 2.14V.

Max-10-2.5mm-a-100-Ohms-a-0dB_resize.jpg


The 2.5mm output, connected to 100Ω at 6dB volume, has no saturation, at 4.13mW, and the power is 170mW.

Max-11-2.5mm-a-100-Ohms-a-6dB_resize.jpg


It can be seen, then, in spite of the visual measurements, that the Qudelix-5K, for the 3.5mm output, at 32Ω, offers more power than stated (110mW), clearly exceeding the 80mW indicated in the specifications.

Something similar happens with the 2.5mm output, capable of reaching 270mW, for 32Ω, which is a great power figure, higher than the 240mW declared.

In the following picture you can see the frequency response, from 5Hz to 40kHz. You can see that the response is completely flat, from 20Hz to 30kHz:

Qudelix-5K.png

Finally, below are the measurements taken with the oscilloscope, without load, making a frequency scan, from 20Hz to 20kHz, using the maximum volume (0db and 6dB), for both outputs.

3.5mm Output at 1V:

FR-01-3.5mm-1V-20Hz-500Hz_resize.jpg

FR-02-3.5mm-1V-1kHz-20kHz_resize.jpg


3.5mm Output at 2V:

FR-03-3.5mm-2V-20Hz-500Hz_resize.jpg

FR-04-3.5mm-2V-1kHz-20kHz_resize.jpg


2.5mm Output at 2V:

FR-05-2.5mm-2V-20Hz-500Hz_resize.jpg

FR-06-2.5mm-2V-1kHz-20kHz_resize.jpg


2.5mm Output at 4V:

FR-07-2.5mm-4V-20Hz-500Hz_resize.jpg

FR-08-2.5mm-4V-1kHz-20kHz_resize.jpg


Sound

Thanks to the ability to connect to multiple sources at once (Bluetooth and USB DAC), it is easy to switch quickly between them, just by pausing one and resuming the other. In this way it is very easy to make comparisons between the two connections. The fundamental conclusion is that there are hardly any differences between the two sources. With medium or low range headphones and MP3 files at 320 Kbps, I would dare to say that the differences are almost indistinguishable. If I were to carry out blind tests, playing the same files, I don't think I would be able to distinguish either the differences or the origin of the source. This is something that has really surprised me. With the Qudelix-5K it is no longer necessary to have a DAP, if our Smartphone has LDAC and a sampling rate of 660kbps, or more, it is totally sufficient. And it doesn't matter if it has been tested for the 3.5mm or the 2.5mm output.

To find some differences you would have to go to great files, very well recorded music and use the best headphones you have. But even so, the results are very similar, bearing in mind the limitation that, by USB, you can only play files of up to 96kHz (a value which, on the other hand, is quite high). My feeling is that, via USB, there is a greater sense of dynamics and that the recreation of the scene is more rounded, with greater depth and three-dimensional effect. But the extraction of detail and the presentation of the sound are really on a par.

Speaking purely of sound, the profile of the Qudelix-5K is quite neutral, I don't find it to be an amplifier, either warm, dark or overly bright. Its balance is perfect for respecting the signature of the connected headphones. In this sense, you can notice that the DACs used are SABRE, where the quality of the details and the resolution capacity are quite exposed. On the other hand, I think that the 5K is not completely analytical, but it is true that it has quite an inclination towards that profile, more than another declared soft. In my case, this type of sound is very much in line with my preferences, which is why, from the very first moment, the device has taken over most of the time, as an audio player, on my desk.

The reproduction of the lower area is perceived as extremely clean, very well shaped, with a good resolution drawing, but without too much roughness, showing that more analytical and defined presentation. The depth is good and the separation of planes is on a par. But, really, it is not an amplifier that enhances the bass or gives it a higher weight than other bands. The balance it has is very noticeable, as well as the respect for executing the area with greater resolution, allowing its background to be quite clean and airy, achieving a fairly decongested and luminous sound.

These qualities benefit greatly from the needs of the mid-range. I do not understand that the 5K is a mid-center amplifier, but its characteristics are capable of enhancing the details and nuances of both the voices and the instruments. Its dark background, above all because it is balanced, gives great dynamics to the sound, as well as definition, transparency and quite high resolution capacity. Thus, the voices appear very natural and very well defined, accompanied by the perfect distance, between the accompanying instruments.

I find that one of the best qualities of the 5K is the respect it has for the sound of the connected headphones. It is very capable of extracting many of the virtues of each one of them, but in a very natural way, without the sound feeling forced or artificial. Its high resolution capacity offers a calm listening. Its level of definition does not overwhelm at all. And a good reason for this is the treatment it offers to the treble, drawing them very well exposed, thin, sharp, brilliant, but docile, with a definition at the height of the neutrality offered, accompanied by a large dose of air and separation. From this, we obtain that declared analytic character and its level of separation, which, in sum, is capable of generating a scene of appreciable width, remarkable depth and adequate height. The level of three-dimensionality is not very high, since the stage is observed from the front. But, in this way, the scene persists naturally, escaping any forced unreality.

Qudelix-5K 15_resize.jpgQudelix-5K 16_resize.jpg

Comparisons

Sabaj DA3, Tempotec Serenade iDSD


A three-way comparison between different devices, but of the same price, may be somewhat inconsistent. But, speaking purely of sound, it is totally justified.

Used, all, as USB DACs, the profiles differ between the iDSD and the 5K and DA3. The first is eminently warm, while the other two are more neutral.

Continuing with iDSD, it has the darkest sound of the three, with a more subtle brightness, where details are less exposed. Its sound feels more congested and cohesive, less clean.

The DA3 is harder, its edges are sharper, it's almost the opposite of iDSD. It doesn't have its softness, nor is it as wide, which enhances the feeling of a sharper, even more shrill profile. It has a higher resolution, but its sound lacks the finesse to respect the nuances, in a more polite way, without losing an ounce of the extracted information.

The 5K, stays in the middle, although closer to the profile of the DA3, but clearly improving the resolution level, the cleanliness of the sound and the delicacy of the reproduction. The DA3, however, can be unsettling because of its more punchy sound; with the 5K, you don't get the same feeling. The sound is analytical, but delicate, executed with calm, light, definition and a lot of sharpness. In this way, the notes are appreciated more separated, with more air. The result is bigger, as well as pleasant and not at all tiring. The scene looks bigger than its competitors, with a higher level of three-dimensionality, easily one step above the other two. It can be seen that, the sound is more mature and refined, with more dynamics and transparency, which gives it a more absolute neutrality, allowing a more prolonged use, without neglecting the pleasure that causes its analytical capacity, totally peaceful and calm.

Qudelix-5K 17_resize.jpgQudelix-5K 18_resize.jpg

Fiio BTR5

I do not have this model, but being its maximum potential rival, I think it is interesting to attach its differences, shown in the following image with the comparative table:

Qudelix-5k-vs-Fiio-BTR5.png


Conclusion

I haven't been this excited about an audio device in a long time. This lightweight device has stolen my audiophile heart, from the very first note. I would say more, since the first Bluetooth wave. I must confess that I am a sceptic of Bluetooth: I think there could be better data transmission alternatives, with higher bandwidth, better bit rate and speed. Bluetooth has been extended and stretched, to meet some needs, based on a specification that, initially, was not intended for such use, at least with great quality. But then, comes that codec, called LDAC and the implementation of Qudelix, based on the Qualcomm QCC512X platform. And here, is where things change. With the 5K, I was able to combine USB and Bluetooth sources immediately. In this way, it's very easy to look for the 7 differences... or rather, not find any. This has been the myth that has demolished the 5K: the shortcomings of Bluetooth are not in the specification, but in the codec and the subsequent amplification. And that is where Qudelix has embroidered it: it does not matter where the music comes from because its quality is practically the same. And I'm not talking about average quality, but in absolute terms, even higher than its selling price.

The Qudelix-5K is a complete and highly versatile device: it is USB, DAC, amplifier, Bluetooth receiver and has a microphone for making calls. In addition, it is ultra simple to use and has a high level of APP, which allows you to control every detail of all the functions it has. It has a 10-band PEQ/GEQ equalizer, long battery life, 3.5mm and 2.5mm outputs and plenty of power, plus a host of configuration options. A technological achievement and, most importantly, a great sound. Needless to say, nothing more is needed.

Qudelix-5K 19_resize.jpgQudelix-5K 20_resize.jpg

Earphones and Sources Used During Analysis

  • HiBy R3 Pro
  • Xiaomi Redmi Note 8 Pro
  • Tempotec Variations V1-A
  • SWD2LE
  • Smabat ST-10
  • Ikko OH10
  • NF AUDIO NM2
  • BGVP ArtMagic VG4
  • ISN H40
  • NS Audio NS5 MKII Extra Bass
  • Moondrop SSR
  • TFZ Live 1
  • Takstar Pro 80

Qudelix-5K 21_resize.jpgQudelix-5K 22_resize.jpg

Ratings

  • Construction and Design: 80
  • Accessories: 55
  • Connectivity: 93
  • Sound: 93
  • Quality/Price: 95

Qudelix-5K 23_resize.jpg

Purchase Links

Main Store:
https://www.qudelix.com/collections/frontpage/products/qudelix-5k-dac-amp

Amazon US:
https://www.amazon.com/dp/B088F7C976

AudioHeaven Poland:
https://allegro.pl/oferta/qudelix-5k-dac-amp-2x-es9218p-ldac-aptx-adaptive-9418697083

Munkonggadget Thailand:
https://www.munkonggadget.com/product/dac-amp-Qudelix11365001_5415.html

THZC Trading Limited Hongkong:
https://item.taobao.com/item.htm?ft=t&id=624617682597

XChesser Audio Russia:
https://xchesser.ru/catalog/product/qudelix-5k


You can read the full review in Spanish here
Last edited:
meringo
meringo
Incredible review. Thanks!
  • Like
Reactions: cqtek
cqtek
cqtek
@meringo, thank you very much for your words. However, the review of the comrade @Zelda, was on the cover of Head-Fi.org and mine never came out. I must understand that his review is better, so read his review too, it's very interesting.
Greetings.
Pancakess
Pancakess
hi, would 5k be worth it for $170? i really like the look companion app.
Top