iFi audio iDSD Signature

General Information

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100+ Head-Fier
iFi Micro iDSD Signature : Breaking All Barriers
Pros: + Excellent Build & Design
+ Great features : 3D+ & XBass+
+ 4100mW output @ 16Ω
+ Balanced output through 4.4mm plug
+ Lower noise
+ Excellent channel separation
+ Excellent Staging & Imaging capabilities
+ Dual Burr Brown DAC chips
Cons: - Separate USB charging required
iFi Micro iDSD Signature : Breaking All Barriers



I have bought this DAC/AMP with my own hard earned money at FULL PRICE and no one has paid me anything or supplied me with any review unit. So, everything mentioned in this review are purely my own based on my experiences with the DAC/AMP.


When I think about iFi DAC/AMPs, the first thing that comes to my mind it that it will be fun sounding. I have bought and used quite a few of iFi products and I loved most of them if not all. They are not the sterile type like studio analytical use - and iFi packs lots of fun & punch into their units that are are just great for music be it on the go or at home.

The iFi Micro iDSD Signature however is a compact powerhouse packed with loads of very useful features which make it very versatile for the price bracket it comes in - $650

Specifications & Technicalities:

Please find below the specifications as published on iFi website:



Digital InputsUSB 3.0 type A “OTG” Socket (USB2.0 compatible/with iPurifier® technology built-in)
S/PDIF (3.5m coaxial/optical)
OutputS-Balanced: 4.4mm
SE: 6.3mm/RCA


DACBit-Perfect DSD & DXD, PCM DAC by Dual-core Burr Brown
ClockUltra low jitter GMT Femtosecond Clock
Octa/Quad/Double/Single-Speed DSD,
DXD (768/705.6/384/352.8kHz),
Double/Single-Speed DXD
PCM (768/705.6/384/352.8/192/176.4/96/88.2/48/44.1kHz)


DSDExtreme/Extended/Standard Bandwidth
DXDBit-Perfect Processing

Line Output

Dynamic Range (Line)>117db(A)
THD & N (0dBFS Line)<0.003%
Output Voltage (Line)>2V
Output Impedance<240Ω
Jitter (correlated)Below AP2 test set limit

Headphone Power Output

Turbo ModePower (max)10.0V/4,100 mW
Power (continuous)>1,560 mW @ 64 Ohm
>166 mW @ 600 Ohm
Normal modePower (max)5.5V/1,900 mW
Power (continuous)>100 mW @ 300 Ohm
>950 mW @ 32 Ohm
Eco modePower (max)2.0V/500 mW @ 8 Ohm
Power (continuous)>250 mW @ 16 Ohm
Dynamic Range (HP)>115dB(A) (Eco Mode, 2V Out)
THD &N (HP 500mW/16R)< 0.008%
Output Voltage (HP)>10V (Turbo Mode)
Output Impedance<1Ω (iEMatch not engaged)
Maximum Output Power4,100 mW @ 16 Ohm Load
Continuous Output Power1,000 mW @ 64 Ohm Load

Other Specs

BatteryLithium-polymer 4800mAh
Power SystemCharging via USB-C, BC V1.2 compliant up to1500mA charging current
Dimensions172 x 67 x 27 mm
6.8" x 2.6" x 1.1"
Weight295 g (0.65 Ibs)

The iFi Micro iDSD Signature is a DAC/AMP for desktop or portable use with practically every feature iFi has implemented into their previous units that worked out well.
It has so many useful features that I am having a rough time finding how to describe them all.

The internal battery that can power the unit for up to 12 hrs depending on the IEM or headphone being used. The battery has a dual function here.
Since batteries don't need to convert AC power to DC, the unit can be charged even with a dirty power source because this unit has iPurifier technology built-in.
You don't need to worry about interference, noise, or voltage anomalies from the power source with this power source design.

Another great upgrade from their previous models is the upgraded iFi custom ultra-low noise OPamp OV2028 on the digital end and another iFi custom chip on the analog side which is labeled the OP2627. These are wide bandwidth capable chips & are low noise devices that very low distortion.

Also, iFi Micro iDSD Signature comes with DUAL Burr Brown DAC chips. Doubling the DAC chips results in a 3-decibel reduction in the noise floor and better channel separation not to forget the improved power supply circuitry design. Noise has been reduced to half the level of past models. Details retrieval and micro-dynamics have also significantly improved over other iFi models.


Also, some of the nifty features that it has but I'm not going deep into are below:
- Selectable Power Output: This let's you choose how much power you want for your IEM/Headphone
- Choose your IE Match Level: This let's you calibrate level of IE match depending on how sensitive your IEM is
- 3D & xBass: This can enable either holographic 3D like surround OR extra Bass or both.


Packaging & Accessories:

The iFi Micro iDSD Signature DAC amplifier comes inside a white box with an outer printed sleeve.


Inside the box you get a USB-C charging wire, a USB wire with full-size plugs for PC connectivity, a set of stereo RCA wires, a full-size USB gender changer, and the 3.5mm optical adapter. You also get a 6.35mm to 3.5mm headphone plug adapter. Some rubber rings to couple the unit to a source are also included. You also get a velvet carrying pouch.



Items used for this Review:

Shanling UA2, IFI Micro IDSD Black Label Signature

DAP/Source : @DUNU-Topsound ZEN, JH Audio Roxanne (Customized IEM), DUNU SA6, TRI Audio Starshine, @FiiO FH5S, @UniqueMelody 3DT, Tinhifi T5, BQEYZ Summer

Streaming Source: QOBUZ

Plugs & Connectors: Both 4.4mm balanced and 3.5mm connectors used for the review





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

Let's now talk about the quality of Sound....


Due to the warmish tuning of the Burr Brown chip the bass is very detailed airy & textured all throughout. It is able to retrieve insane amount of micro-details while retaining quality & texture and rumble and punch. The bass packs some punch & thump also. Even the IEMs that seem to lack Bass body & details on some other gears seem to work well here. This is just a superb quality iFi has


Mid-range is detailed, textured, airy with wonderful micro-details and nuances... one can easily get lost here.
It's just so smooth and beautiful... be it Guitar or Piano or Cello or Violin... there is excellent separation and each of the instruments sound very real.
Both Male & Female vocals sound great with ample amount of details down to the the tiniest nuances like breaths they take while singing can be heard clearly.

The Treble:

While it cannot be considered bright in any way - The iFi Micro iDSD Signature has superb Treble overall and in a very clean and non-fatiguing way.
Even IEMs that have some peaks in the treble region sound much nicer while retaining the details.
Treble here is full of texture, air, micro-details and rich sounding. The sound is just clean and refined here.
No peaks to be found anywhere - and it is quite forgiving for quite a few tracks that have unusual peaks.


The staging capability is amongst the key strengths of this DAC/AMP. It is massive & immersive. Both in terms of width and depth.
Nothing artificial. only as much as the track requires it to. turning the 3D+ ON enables holographic staging... given that your IEM or Headphone is good enough to support it can be truly immersive.

Imaging & Timbre:

Sense of direction is spot n and also gives a notion on depth/height. You can clearly understand where the instrument of the voice sound is coming from and how far it is from you. In terms of Timbre it is amongst the best I have come across so far and very real.


In short I have found this iFi Audio Micro iDSD Signature DAC/AMP to be very resolving, detailed, textured, natural and just superb sounding.
It is clearly the BEST from the house of iFi in terms of portable DAC/AMPs and likely the best in similar category also.
While the price bracket remains quite high - I would say that every penny is well-spent on this taking into account the value that it gives.
It's just a great sounding Desktop grade DAC/AMP that you can easily carry around with you.
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100+ Head-Fier
Pros: Solid build with very nice design

4,100 mW output at 16 Ω!

Balanced output through 4.4 mm jack

Cons: Requires separate USB-C cable for charging

Loses lots of options compared to predecessor

Charge indicator is impractical

Pops when it powers up and down
iFi micro iDSD Signature review.JPG

Just when I thought that iFi was done with the old "micro" line-up, they come up with a new device that promises to make their best portable DAC and amplifier even better. The all-new iFi micro iDSD Signature is an evolution over the previous micro iDSD Black Label that introduces a small yet quite significant addition: a balanced headphone port. Most of what everyone (me included) loved about the Black Label is here as well, sometimes with improvements that make the Signature stand out.

Disclaimer: thank you to Karina at iFi for sending me a unit to review. The official website holds more information.

This review was originally posted on
Soundphile Review.

Packaging & Accessories​

iFi micro iDSD Signature review 2.jpg

iFi kept the packaging identical, with the typical rectangular box shape. Inside the box are a USB 3 cable (with two A connectors, one male and one female), a USB-C cable to charge the device, a black fabric bag, an RCA cable and a manual.

Design & Build​

iFi micro iDSD Signature review 3.JPG

There's not much to say on the iFi micro iDSD Signature that I haven't already said about the Black Label as the two are identical in all respects, save for a few details. The first is the colour of the metal: it is now a dark blue, with text printed in white. The second is the front and the back: they don't have the protrusions that characterised the BL, instead opting for design that reminds me far more closely of the nano iDSD Black Label. The front also has a different arrangement due to the inclusion of a 4.4 mm jack port and a status LED, which are added to the 6.3 mm jack, the XBass+ and 3D+ switches, and the volume knob; the 3.5 mm input is gone. The third is that there is now a USB-C port on the side instead of the USB-A one, so charging the micro iDSD Signature should be easier now. The various switches that were on the bottom (power mode, filter, IEMatch) are now on the side so they're easier to reach. A couple of switches, the preamplifier type and the polarity, are missing.

iFi micro iDSD Signature review 5.JPG

The micro iDSD Signature seems like a modernised, streamlined version of the Black Label. It has a couple of additional options, but it also loses a couple so there's no definite answer as to what is better. If you wanted a device that could work as an amplifier only, for example, then the Black Label is better for you.

A very minor detail which I liked is that the Signature has built-in rubber feet. Those prevent the Signature from resting directly on the surface below it and from scratching it.

iFi micro iDSD Signature review 4.JPG

The knob offers some resistance to turning, so it has a "weight" that makes it possible to turn it with precision. It has quite a large "dead zone" in which no sound is produced even when using very sensitive earphones: it extends from its starting position around 7 o'clock up to 11 o'clock. It doubles as the power button, so once you turn it from its starting position it also powers the device up.

Features & Specs​

iFi micro iDSD Signature review 6.JPG

The iFi micro iDSD Signature trades the coaxial S/PDIF port for a 3.5 mm one, which doubles as an optical input. This lends the device added flexibility as you can use it with a huge number of sources that offer coaxial or optical but not USB (e.g. TVs, just to name the most common devices).

iFi embedded its IEMatch technology in the micro iDSD Signature, so that you can use lower-impedance earphones. It's basically applying a lower gain (e.g. 0.5x) instead of a higher one. One thing to watch out for is that this alters the output impedance and makes it higher than it normally is, so you could actually want to have a real IEMatch device to keep the impedance low if you have earphones with especially low impedance.

Just like the Black Label, the Signature also has a somewhat loud "pop" sound when it is powered up or down. It is far quieter than the previous model, though, so there has been an improvement in that regard, but it's still there. Honestly, I would expect it not to be present at all, given the price point of this thing. On the other hand, the one-second gap that was there on the Black Label is gone, thankfully, so the micro iDSD Signature is actually playing music as soon as you start playback. That's quite an improvement over the previous device!

The largest news in terms of supported formats is MQA, which is now supported out of the box and requires no special firmware installation.

iFi micro iDSD Signature

Input range16 - 32 bit / 44.1 - 384 kHz PCM, 352 - 768 kHz DXD, DSD64, DSD128, DSD256, DSD512, 88.2/96/176.4/192kHz MQA
Suitable headphones impedance16 - 600 Ω
Output impedance< 1 Ω (without IEMatch)
Maximum output power500 mW (8 Ω, Eco mode)
1,900 mW (16 Ω, Normal mode)
4,000 mW (16 Ω, Turbo mode)
1,560 mW (64 Ω, Turbo mode)
166 mW (600 Ω, Turbo mode)
Frequency responseN.D.
THD+N (@1 kHz)< 0.008%
SNR115 dB
Crosstalk79 dB

The micro iDSD Signature is identical to the micro iDSD Black Label from the standpoint of specs: it is built on the exact same foundation and offers the same output and specs down to the bit.

Just like all other iFi products, the micro iDSD Signature also uses Burr-Brown chips; unlike the Neo iDSD, though, it uses two DAC chips that produce a dual-mono signal which is then taken care of by a dual-mono amplification stage. This is not a "true" balanced design in the sense that there is no interleaving, it's a double-mono design with a balanced connector. This means that you can get many of the benefits of balanced designs, but it could be noisier than a "true" balanced signal pathway.

Like its predecessors, the Signature offers three modes: "eco" (low-power), "normal" and "turbo". If you're wondering, yes: the micro iDSD Signature is more than enough to power the HiFiMAN HE6 SEv2. It has in fact loads of power more than is required to bring it to literally deafening levels: with just 700 mW those headphones get to 112 dB, which is enough to make you deaf in less than a minute, and the Signature is more than capable of delivering that power, given it outputs 1,560 mW of continuous power at 64 Ω (meaning that peak power output is even larger than that). You will probably become deaf if you push the device at full volume.

Battery Life​

The micro iDSD Signature offers a full working day of usage in "normal" mode. In "eco" mode you can actually go throughout your whole day, if you exclude meals. That's quite impressive, given the amount of power this thing dishes out! It also takes a while to charge: even using "high-powered" chargers (2 A @ 5 V) it still takes 3 hours. If you use a generic 0.5 A USB charger it takes 12 hours. Luckily most of today's chargers are more than capable of offering 2 A.

That's all good, but there's also a problem: there is unfortunately no way to know how much battery is left, unless you look at the tiny little LED on the side near the USB-C port - though that's not really practical. The micro iDSD Signature has no other indication that you're running out of juice, so if you don't realise in time you will just see the device power off and stop producing any sounds all of a sudden.

The battery also doesn't charge if you simply connect the unit to a computer using its USB cable, like previous iDSD units did. This makes having a second cable almost mandatory if you are going to use the micro iDSD Signature as a desktop device.


I spent a good amount of time trying the iFi micro iDSD Signature with various headphones; among them are the Moondrop A8, the HiFiMAN HE-R10P, the Sennheiser HD 6XX and the Fearless Audio S10 Genie. Most source files stored on my computer were FLACs in 16 bit, 44.1 kHz resolution.

As far as I can tell, the micro iDSD Signature introduces no colouration to the sound. I switched back and forth between it and my Drop THX AAA 789 and I couldn't hear any differences in tone, nor in resolution nor in technicalities. It's dead neutral.

Keeping with its own tradition, iFi provided the micro iDSD Signature with the XBass+ effect: a bass boost which the company highlights as being entirely made in the analogue domain. It works quite well and adds a good oomph to the lower end. In fact it adds quite a substantial amount to the sub-bass section, diminishing it as the frequency goes up. The effect is quite good as it adds some kick to the sound, but it doesn't make bass become overbearing. Among bass boost implementations I've heard, this is one of the finest.

3D+ is the soundstage enlargement tech iFi developed. It makes soundstage much wider by giving more emphasis to frequencies in the upper midrange and lower treble region and the effect is quite astonishing - one moment you are in your own room, the next you are in a concert hall. While it doesn't fix depth, the width increases significantly. It's not perfect, as you can hear that there is a change in tone, but it's extremely fun.

The filter switch allows you to choose between bit-perfect, minimum phase and standard. The difference, if it's there, is so small you can't really hear it. Even with the S10 Genie, which has very low impedance and high sensitivity plus an astonishing ability to render detail, I can't hear any difference between them.

iFi micro iDSD Signature Comparisons​

Although I've already spread bits and pieces of this comparison throughout the review, I'm going to do a more thorough comparison of the micro iDSD Signature and micro iDSD Black Label. The largest differences are:

  • design: the Black Label is black, while the Signature is blue; the latter has a status LED on the front, while the former has it on the top;
  • rubber feet: the Signature has rubber feet built-in;
  • USB: the Signature adopts the USB-C standard, whereas the Black Label uses USB-A;
  • balanced output: the Signature edition has 4.4 mm balanced output;
  • S/PDIF: the Signature only has an input here, while the Black Label offers output as well (meaning you can use it as a bridge between devices);
  • preamp mode switch: the Black Label has a switch to select either preamp mode or direct mode, the Signature does not;
  • polarity switch: the Signature loses the polarity switch;
  • headphone amplifier: the Black Label can also work as a pure amplifier thanks to the 3.5 mm jack on the front;
  • charging: the Signature does not charge when connected to the computer or other source through USB;
  • availability: the Signature is not available as an audio device on the computer while it's powered off, so you have to power it on and then select it in your operating system's audio menu.
Everything else is the exact same in all regards that matter.

Much to my surprise, there is a slight sonic difference between the two devices. I expected them to be 100% identical, so you may say that I started comparing them with a bias, but that turned out not to be the case. The Black Label is in fact a tiny bit warmer than the Signature! It sounds fuller and with better extension in the sub-bass section, whereas the Signature appears slightly more resolving. It's a very subtle difference, yet it's noticeable.

The Signature is not a perfect replacement of the Black Label, so if you are in doubt over what to buy you should think about what features you need the most or if there is any blocking issue with any of the two. Also, if you already have the Black Label, don't think of the Signature as an upgrade: it's a different beast that does different things and it's not a drop-in replacement.

Final Thoughts​

The truth is that, however you look at it, iFi's micro iDSD line has virtually no competition. No other portable device in this size and price class can shell out as much power while boasting a comparable battery life and with similar accessory features. This is really the Ferrari of portable DACs - and you pay for that, but it's a fair price for the features, a bit like Ferrari cars. The streamlined design, the great build quality, the large amount of options and the incredibly high power output all concur to making the micro iDSD Signature a great device, possibly the best portable DAC/amp under $1000. It's an option you should definitely consider if you want a device to power all of your headphones at the desk as well as everywhere you take it.
@Slater91 thank you for a great review and especially detailed comparison with Black Label. In my book this is the best Signature review I've read so far, and definitively best on head-fi.
@alekc Thank you so much for your kind words!


100+ Head-Fier
The Right Signature for Your Sound Signature
Pros: Extremely capable DAC with upgradeable Firmware that can affect SQ
Full bodied neutral sound with impressive detail
Amazing Soundstage
Solid Build Quality
Versatile - many features and sound customizations
Crazy good power capabilities
Can drive virtually any set of headphones with ease
Cons: Size can be a bit big for some for a "portable" device
That teeeeeny tiny little battery indicator
Channel Imbalance at super low volumes
xBass not as versatile as xBassII on xCAN

Before I begin, I just wanted to send out a special thank you to Karina from ifi Audio for providing me a temporary loaner unit for the purpose of writing this review. I am ever so grateful for this wonderful opportunity.

Another little tidbit before I begin, this is my first major review on Head-Fi for any piece of audio equipment aside from impressions of various headphones and the like that I've posted in various threads. So with said, I hope this review will provide useful and educational information for people trying to get an idea of how this DAC sounds and seeing if it's a right fit for them or not. So with that said, lets jump right in!

Packaging and Box-o-goodies!


When I first got the Signature, I was a little surprised at how small the box was. For the amount of power this thing can put out, I was expecting a much bigger footprint. This could be my inexperience or ignorance about never seeing/hearing the micro iDSD BL, but nonetheless, it was a pleasant surprise to see that it wasn't the size of an XBOX 360 power brick. Man those things were huge....!

So inside the box comes with a slew of accessories.

The list includes:
- 6.35mm adapter
- USB OTG cable, adapter OTG
- 2 rubber bands for stacking
- optical adapter
- RCA cables
- carrying pouch
- USB-C cable
- manual
- warranty stuff

I was pretty impressed with the packaging and how everything was neatly packed in smaller boxes in their own compartments. Very neat and organized. The only thing I find missing in this set is a 4.4 balanced adapter. Personally I didn't mind too much because I had 2 of my own, but for someone that only has a 2.5mm balanced cable would need to shell out some extra cash for a quality adapter. But truth be told, if I had to choose between having only 1 adapter, I would have gone with the 6.35mm adapter for sure. For someone like me that only owns IEMs, a 6.35mm adapter is not something I just have lying around. But if 1 adapter is already included, why not the whole set? But no biggie. Just a small nitpick.


Battery Life

Generally I don't pay too much attention to the battery life on my DAC's because I hardly ever use them on the go. I primarily use them as Desktop units when I'm at work and pretty much have them charging while I'm listening to them. But for the purposes of this review, I did let the battery run down a few times on various power stages just to see how long it lasts. And I must say, for it's 4800mAh size battery, it does a great job of providing enough juice for long listening sessions.

When I first got the Signature, I listened to it straight out of the box on Normal mode with no xBass+ or 3D+ for about 2-3 hours straight while it was still on the green indicator. I'd say keeping it on Normal mode listening at moderate volume levels will last for about 6-8 hours from my experience. When put in Eco mode, you'll get even more battery life out of it. But bumping it up to Turbo mode its another story... This is the highest power stage of the Signature and thus, sucks up more juice given its higher power stage and demand on the battery. For the headphone configuration I was using, I found myself putting it on Turbo mode a lot (mainly because I like to listen to music at deafening volume levels), but I found the battery life to be about average. About 4 hours or so tops if solely using Turbo mode. Which again, is fine by me, seeing that I can just plug it in whenever it gets to the red indicator.

Speaking about the indicator, I don't think I've ever seen a smaller one on a DAC this size. Like ever. I can understand the idea of maybe taking the minimalistic approach or putting things in common locations like a battery indicator right next to the charging port, but the indicator is just so darn small that you gotta be looking directly at it at a distance of 6 inches or less to see it clearly! If it was bigger then I wouldn't have listed it as a Con in this review. Or if you wanted to keep it the same size, at the very least move it to the front of the device for easy viewing.

I always find myself physically turning the device as Im listening to it just to get a glimpse of battery indicator. But in the grand scheme of things, it really is a small nitpick. It's more of an annoyance than anything. Now if there was no battery indicator at all, then I'd be docking some points on this review, but that's not the case thankfully.

Before I say anything in this section, I have absolutely zero experience with the SPDIF input, so I will not be covering any information on it. I primarily used the Digital Input as my main source for connecting to my computer.

With that said, the Signature has two main inputs - SPDIF and Digital. Again, I exclusively used the Digital Input with my setup and gear.

On the Output side of things, its a quite interesting affair here. It has 2 headphone jack outputs:
1) 6.35mm SE Output
2) 4.4mm S-Balanced Output

In addition to these two headphone outputs, it also has a Line Out RCA SE Output in the back of the unit.

Now here's the interesting part with the Outputs. All of the Outputs on the Signature can be used to feed into another Amp of your choosing, but the RCA Line Out is the only one that bypasses the amp in the Signature and treats it as a true line out, as opposed to the 6.35mm and 4.4mm outputs where it goes through the Signatures amp and also enables the use of xBass+ and 3D+. The RCA Line Out disables these features. Here's a table to better explain:

OutputSE/BalancedxBass+3D+Bypass Internal Amp

Honestly, I didn't mind which output I used because it all sounded great whether I was using RCA, 6.35 or 4.4. The only thing I will say is that I've noticed when using the 4.4mm Balanced Output, whether using it as a line out or directly plugged into my headphones, there was a noticeable difference in instrument separation and better definition overall - especially in the highs compared to the RCA and 6.35 Outputs.



The Signature has 3 filters that you can select from. Here is excerpt directly taken from the user manual:

DSD: Extreme/Extended/ Standard Range (analogue) filters
PCM: Bit-Perfect/Minimum-Phase/Standard (digital) filters
DXD: Bit-Perfect Processing (fixed) analogue filter

Tip: For PCM we recommend ‘Bit-Perfect’ for listening and ‘Standard’ for measurements. For DSD, select Extreme/Extended/Standard to find the one that sounds best for listening and ‘Standard Range’ for measurements.

Unfortunately I didn't have any music in DSD format to try with the Signature, So I can't speak to that point. I primarily listen to Tidal and Amazon Music HD and tested everything from HD (16-bit 44kHz) to UHD (24-bit 96kHz) to MQA. I found that Bit-Perfect was the "best" and most expansive and spacious sounding filter for me.

After doing the initial test between all 3 filters, I ended up settling on Bit-Perfect and never changed it again.

I have to be honest here. I didn't really pay much attention to the Firmware versions out there for the Signature for the majority of time I had with it, because A) I didn't know the Signature had different firmware versions, and B) I didn't know there would be any sonic difference between the firmware versions.

For the last month or so, I've been listening to the Signature with the base 1.0 firmware out-of-the-box, and I was quite impressed with its performance. When I learned about the different firmware versions available for the Signature, especially the 7.0c GTO firmware, it just made everything sound that much better! The firmware upgrade offerings are as follows:

7.0 - It supports MQA, DSD (up to 256) and PCM (up to 384kHz). This will probably suit most people's sound processing needs, especially if you just stream music and don't have any uber high quality music.
7.0c - The most interesting firmware of the bunch - the 7.0c firmware is the GTO filter variant which replaces the Minimum Phase Filter and upsamples USB audio. The only negative impacts this firmware has is that it has no GTO for SPDIF signal, no DSD512 and no PCM 768kHz. Other than those negatives, this firmware is probably the best of the bunch, adding tighter bass response and more body to the overall sound, and to my ears, improved the attack of each note more accurately.
7.2 - Supports DSD (up to 512) and PCM (up to 768kHz). No MQA support. This is the firmware you want when you have super high audio samples and want to hear them in all their wonderful glory.


Plain and simple, the Signature has power for days... Just like its other sibling, the micro iDSD Black Label, the power specs are very similar. With a max power output of 4100mW (in Turbo mode), the Signature can power virtually any set of headphones out there with ease.

I primarily have IEM's and don't need all the raw power Turbo mode has to offer, but with the addition of impedance adapters in series with some of my IEM's (mainly the Thieaudio Monarch), its almost necessary to use Turbo mode get the volume I want out of them.

Just like the filters, the Signature also has 3 power stages - Eco, Normal and Turbo mode.
Eco Mode - 2V/500mW @8 Ohm (Max)
Normal Mode - 5.5V/1900mW (Max)
Turbo Mode - 10V/4100mW (Max)

For most users that value their hearing, Normal mode is all you'll ever need.

Sound Impressions

Ah yes... The meat and potatoes of the review! Just what I've been waiting for. :)

I'm a man of function over form. Especially when it comes to audio equipment and gear. Sound Quality, to me personally, trumps all. The DAC/DAP/Headphone can be the most beautifully constructed work of art with all the bells and whistles attached with everything that audio technology has to offer, but what is it worth if it doesn't sound any good?

Fortunately for the ifi micro Signature - in addition to the build quality, construction and features, the sound is top notch and puts a smile on my face every time I listen to it.

If I had to pick 3 words to describe the Signature, they would be: TRANSPARENT - DEFINED - FULL BODIED
Ok maybe 3.5 words... :)

Transparency & Definition
The Signature offers a very clean, transparent and well-defined sound to my ears. Listening to it straight out of the box without touching any of the filters, firmware or add-ons (xBass+/3D+), it provides an enjoyable listening experience with no coloration of any kind from Bass to Treble. This creates a cohesive and extremely smooth sound where nothing sounds disjointed. But to me, sounding smooth isn't enough. Smooth sounding DAC's are a dime a dozen these days and this would just be one more added to the mediocracy category.

But with the addition of impeccable definition and articulation - each note is discernable and is crystal clear where a note begins and ends. It also make's it super easy to pick out and clearly discern different instruments as well as heightened instrument separation. This is extremely important when listening to music with a lot of layers.

But even still, this to me is not enough to justify a 5 out of 5 score. Which leads me into my next section....

Full Bodied Sound
With transparency and definition in check, these by themselves would make the sound quite flat and not very exciting. But thanks to the full bodied nature of this DAC, every note has weight, impact and purpose. There isn't a single note that sounds just... "meh". Everything sounds like its meant to be there and with authority.

Another added perk of having such a full bodied sound make's everything sound very three dimensional. There's plenty of space here, and each note takes up every bit of that space - creating very pleasing note texture.

The other benefit of having such a full bodied sound is that it adds much needed thickness to thin sounding headphones.

Personally I have experienced this and is probably the reason why I fell in love with this device. It gave me something that I was lacking with all my other devices. I have the Thieaudio Monarch's which sound amazing by way of its tuning but is also known to sound somewhat thin in the upper bass and lower mids region. I have tried virtually everything in my arsenal of audio equipment to make these IEM''s sound fuller and add more mid bass impact. I've done everything from tip rolling, cable rolling, changing out sources and every possible permutation of the like, and I couldn't quite find that sweet spot.... until I tried the Signature.

As I mentioned earlier in this review; as soon as I got this device, I listened to it for about 2-3 hours straight. Just playing track after track, with no sign of OCD tendencies to "tweak this" or "switch out that". Just pure audio enjoyment and satisfaction. This was with the very same Monarch's that I've tried everything under the sun (well everything that I own anyway...) to realize its full potential, but nothing came close to what the Signature did for me with my Monarch's.

Another thing the Signature did for my Monarch's was that it cleared up some inconsistent coherency issues I had with the bass. The bass driver configuration uses a 10mm Dynamic Driver in conjunction with 4 BA woofers. The issue here is that the blending between the dynamic driver and BA's caused the bass to have inconsistent behavior when reproducing the sound from track to track. Sometimes it sounds amazing. And sometimes, not so amazing...

But with the transparent, defined and full bodied sound of the Signature, it reigned in the bass and made it sound extremely coherent and very well controlled on a consistent basis. Every track I threw at it, it reproduced the bass to sound full and whole - with no questioning about "what's going on down there?" or "Is that the bass or the lawn mower outside??".

Coherency here is simply brilliant.

Sound Add-Ons (Versatility)

In addition to the original sound of the Signature, it also includes a few add-ons that may alter the sound for better or for worse. Generally for the better, but depending on the technical capabilities of the headphones you're listening to, it might be too much for it to handle. iFi Audio has made their in-house technologies, xBass+ and 3D+ available on most of their DAC's.

Personally, I'm a fan of the xBass technology. The beauty of this bass boost feature is that its not DSP, but instead it is ASP. This means that its analogue domain processing and provides sound processing that directly affects the frequency response instead of doing this in the digital realm.

The result are nothing short of impressive. It adds a generous amount of bass boost that sounds clear and natural from sub bass all the way up to the mid bass region.

However sometimes I feel like the xBass+ feature on the Signature can be a bit much at times. And what I mean by this is that if the sound signature of the headphones already have a generous amount of sub bass or mid bass respectively, xBass+ will correct for the entire spectrum and can make it sound a little muddy.

This is why I prefer the combo of the Signature with the xCAN. The xCAN features an enhanced and more versatile version of xBass since its xBassII instead of xBass+. By disabling xBass+ on the Signature and utilizing xBass II on the XCAN, you can set it to "Bass", "Presence" or "Bass + Presence". This gives you the flexibility to correct for sub bass ("Bass") alone without affecting the mid bass ("Presence") and vice versa, while still giving you the option to have both enabled if desired.

I would have loved to see iFi implement the xBassII feature on the Signature instead of xBass+ to allow for the versatility of setting what kind of bass boost you want, but xBass+ is still good in its own right and gets the job done quite well. However, its something that I would have to turn off altogether if it has a negative affect on my music, but most of the time it works well and is sufficient for my needs.

I don't have too much to say about the 3D+ feature, but from my experience, its a welcomed sound altering addition. To my ears, the 3D+ feature is a little more subtle in presentation than the xBass+ feature, but I do find it makes a difference when enabled. I've found that it adds more air up top, thus making the sound brighter and creating the effect of an enhanced soundstage. I generally just leave this setting turned on more times than not.

This really isn't a "sound add-on" per say, but it is a nifty little feature for super sensitive headphones that have a lot of background hiss or require more volume granularity than just throwing it on Eco mode. The point of IEMatch is to create a blacker background and improves the dynamic range, thus increasing the usable volume range.

Personally I don't own highly sensitive headphones such as the Campfire Andromeda to properly utilize this feature, but it hasn't stopped me from trying it out. Honestly, I've had mixed results with IEMatch. I understand the technology behind IEMatch with it attenuating the signal going to your headphones, allowing you to increase the volume and essentially change the tonality, but I've found that the overall sound was a little too muted for my tastes. Even with the volume cranked up, it just sounded like my music was veiled and slightly muffled. But again, for the headphones I own, I'm not the target audience for this feature.

So personally I just leave it off.

So again, the whole point of this section is to show how versatile the Signature truly is. With the inclusion of 3 digital filters, 3 power stages, IEMatch (High and Ultra), xBass+ and 3D+, the Signature has a lot to offer in way of altering your sound to your listening preferences. Simply fantastic.


So to sum things up, I had a wonderful experience with the Signature and truly enjoyed every bit of it. It's a very well built piece of equipment and for the price, its a steal. I've spent hundreds (if not thousands) of dollars in total on various DAC's and this one by far exceeds my expectations and changed my perception of value for what you get in sound quality in this price bracket. I was always of the mind that I needed something in the $1000+ tier to get absolute top tier performance, but the Signature gave me what I was looking for and more.

I've spent a lot of time with the Signature and it is now my go to DAC for when I wanna hear my headphones at their best.

Unfortunately I haven't heard the Signatures other sibling - the micro iDSD BL, but for my tastes and musical preferences, the Signature just does it for me. I've even read other comparisons between the iDSD BL and the Signature saying that the Signature lacks "edginess" and "oompf" compared to the BL, and in relative terms, that may be true. But hearing what the Signature has to offer, I do not find that at all to be the case. From what I've experienced, the Signature is edgy, has tons of body and definition, and may even sound a bit forward at times.

So if you're looking for an all-rounder that has power to drive all your headphones and has an overall well balanced sound, the Signature checks off all the right boxes. I highly recommend!


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its really a shame that they don't tell people that the 4.4mm isn't a true balanced output.... if they had put the guts of the Diablo ( true balanced amp ) into the Signature then they would have had a fantastic DAC/AMP... but they didn't...
Really nice review.
I directly want to upgrade the firmware on my signature :)
Edit: just updated the FW, and the results are amazing. Big thanks @drummguy26 for writing this detailed section in his review
@Dixter yea I agree. It is a shame it's not true balanced.... But nonetheless I still feel like it's a wonderful amp/DAC combo.


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