iFi audio iDSD Signature

I really liked the little hip dac from iFi but I still ran into power issues on more demanding full size headphones. The iDSD Signature fills that need by offering a middle of the pack(in physical size) unit that still allows you to take it in a bag with you out and about yet it still manages to give a good amount of power output as well. Alright, let's get into the review of the Signature!


Thanks to iFi and @Sebastien Chiu for hooking me up with a review unit. While I always appreciate stuff being sent in to test and review, It never affects the rating of my review.

Gear used​

S.M.S.L. SU-9/SH-9, iFi iDSD Neo, THIEAUDIO Clairvoyance, DUNU EST 112, DCA Aeon Noire, Focal Radiance.

Looks and Feel​

I absolutely love the looks of the Signature. It’s a nice long brick that comes in a really nice dark metallic-ish blue color and feels wonderful and well built. The device isn’t too hefty and while you can technically take it out for portable use, It would be harder to fit in a normal pocket with an attached source device. All the space was well utilized as well inside of the casing. One side of the device has switches. The front has the jacks, volume knob and switches all close together and the back has enough room to fit the USB in, RCA out and 3.5 optical in.

Accessories and unboxing​

Inside the box we get an abundance of accessories. iFi includes a set or RCA cables, USB cable, USB-B to A adapter, short USB-C charging cable, optical to 3.5 and rubber rings and a pad to keep things from scratching. I always feel like iFi includes a good chunk of accessories with their gear.

Switches and volume knob​

On the unit's right side we get a power mode switch which acts as low, medium and high gain. The next switch is a filter switch which goes standard filter, minimum phase filter and bit perfect filter. I can only assume the bit perfect filter is a linear phase. I can never really tell the difference between all of these filters on any DAC honestly. The final switch is for the famous IEMatch that helps with super sensitive headphones. Unfortunately I don’t have my set of andromeda anymore for hiss/floor noise testing but the DUNU ZEN picks up hiss via balanced fairly easily so that’s what I used to test the IEMatch. While I can’t confirm it, I could swear the off position provided the best sound. I also didn’t get that much annoying noise out of the 4.4mm jack compared to other gear so it will be personal preference on how quiet the floor noise needs to be. This wasn’t a problem on the ECO mode which was as high as I was willing to go on sensitive IEMs in terms of available power.

Sound(overall)​

These final impressions were done off the iDSD Signature with no external amp usage. This will be what the micro iDSD Signature sounded like with all the headphones I used. Things like headphone pairings or using different external amps will produce different results and impressions vs what my ears hear on my specific gear.


The Signature has a fairly musical sound to everything I plugged in. This is one of the better DAC/amp combos for chilling out and simply listening to music. The lows come in with a slight boost to the sound which makes all the headphones I tried have a little extra thump down low. Mids come in clear with a little warmth that helps with some of the more intense sounding vocals. Same thing with the treble. While it’s fairly clear and resolving, It has a nice warmth that can take the slightest edge off sibilant sounds. The Signature overall sounds like a nice warm amp but it still sounds fantastic and at its price point I have zero complaints about the sound.

Imaging/Soundstage​

The staging has decent width and depth. Not quite as good as some larger desktop gear I’ve tried but I think for a transport device like this, it’s fine. I’ll take a balanced width and depth any day over something that sounds way too wide or way too deep. Imaging is always something that’s headphone dependent IMO but I had no issues with the headphones I tried.

Inputs and outputs​

We get a USB(male) input, 3.5mm optical in and a set of RCA outputs. I think the option for the RCA outputs is a nice touch for a “portable/transport” device like this. I would still like to see Bluetooth in something this expensive since devices like the FiiO Q5 which comes in cheaper and has Bluetooth(at the cost of power output”. I would also prefer a USB-C input instead of their weird full size usb male input. They stay consistent and use it on everything so I’ll at least give them that.

Personal grips with the Signature​

The only issues I have with the Signature are small nitpicking issues. I wish the ECO mode had less power so if I accidentally adjust the volume, I don’t die or kill a set of IEMs. I also wish iFi would use stiffer volume knobs. This is an issue I had with the hip dac. I don’t take the Signature outside in a pocket so it gets a pass in this instance. The volume knob channel imbalance is noticeable from 9(close to off) to 11-ish o’clock. I didn’t have anything super easy to power that produced any imbalance issues but this could possibly be an issue as one set of IEMs was at my preferred volume between 11-12 o’clock.

Single ended/balanced power outputs​

Since the unit isn’t truly balanced, we get the same power output via the 3.5mm and 4.4mm jacks. The power output is fairly impressive and we get a max output in eco mode of 500mW, 1.9 watts in normal mode and finally 4.1 watts in turbo mode. iFi has a terrible habit of not using mW into 32ohm numbers and I didn’t feel like trying to do the calculations personally. What I will say is that eco mode is usually too much for sensitive iems(use IEMatch to solve this), normal mode is good for pretty much everything and turbo mode is only for extreme uses.

IEM pairing opinions​

DUNU EST 112​

The EST 112 is one of my new favorite IEMs for regular use around the house. I found the Signature did a great job of keeping the lows nice and strong. The mids still sound fantastic and the Signature didn’t do much to bump up the treble which is the most lacking part of the 112. There was a little hiss coming from the 4.4 jack.

THIEAUDIO Clairvoyance​

One thing I love about the clairvoyance is how spacious and airy it sounds while still maintaining both a detailed and smooth sound signature. The Clair and Signature make a very awesome pairing IMO and I probably used the combo the most. The balanced staging of the Signature meant the Clair could really shine with its staging without anything sounding off. I got to about 12 o’clock on ECO. Those looking for something to spice up the top end of the Clair will probably wanna look elsewhere however.

Over ear pairings​

Focal Radiance​

The radiance is super warm and super relaxed with its tuning. I found the Signature to be a pretty good pairing. The Radiance isn’t super hard to drive but there was a noticeable difference when I went from the hip dac to the Signature. Lows maintain a nice thumpy impact and the mids still remain somewhat detailed but just a bit warmer than normal. Treble seemed to come in a little clearer and I actually really liked the combo. The staging had a nice balance of width and depth.

DCA Aeon 2 Noire​

The Aeon 2 Noire is a fairly well tuned closed back planar. It does lack a bit of life in the low end so it can come off somewhat lifeless on certain source gear. The same issue remains with the stock iDSD Signature. The overall sound is a little warmer sounding but the lows are still lacking a little life. When the xBass is activated, this brings some of the lifeless bass to a more dynamic sound without causing any distortion. Staging stays the same as compared to my daily amp that I use. Good pairing here.

Amps comparisons​

iFi iDSD NEO​

I’ll paste what I said in my iFi Neo review here.
The Signature comes in around the same price as the NEO. How does it compare sound wise? I think the Signature sounds way better than the NEO. The stock tuning from the amp is somewhat warm but with a nice airy sound. There seems to be more life to whatever headphones I plugged into the Signature after using the NEO. The biggest difference between these two devices will mostly be the inputs and outputs. More input and output options for the NEO which make it a better desktop amp. If you could care less about XLR outs, bluetooth in or coaxial in then I would say grab the iDSD Signature. I think it's worth it over the NEO if you can live without the things I just mentioned. You also get around 4 watts at peak with the Signature which is wonderful for a device so small.

S.M.S.L. SH-9/SU-9​

Both the S.M.S.L stack and the iDSD Signature were competed well here. Both have wonderful detail retrieval for their prices. The biggest difference will come down to staging and the sound signature of the two. The iDSD Sig is warmer and has an in your face sound. The S.M.S.L stack goes for the more treble oriented sound signature. The SMSL feels a bit better in depth as well. Both have a good amount of power output. The biggest thing will come down to what you need for your desktop. The stack has XLR outs, the iDSD Sig only has RCA outs. The Signature is also missing bluetooth which the S.M.S.L stack has.

Overall thoughts​

So at the end of the day would I recommend the Signature? I found no real issues with the Signature outside of wishing it had Bluetooth and a little lower volume output for the eco mode. The device is well built, works well as a desktop unit and can be moved around as a portable-ish unit. The power output is wonderful for a device this size and it sounds great. I think iFi did really well with this release. I had issues with the desktop NEO iDSD and recommended the Signature over it. I think this is a well rounded Swiss Army knife DAC/amp from iFi and the micro iDSD Signature gets a full recommendation! Good job to iFi and thanks for reading!

The packaging is very similar to the BL, its efficient and looks good too,
The Accessories inside includes:
- 6.35mm slimline adapter
- ifi Blue USB OTG cable, adapter OTG
- 2 rubber bands for stacking
- optical adapter
-ifi purple RCA cables
- carrying pouch
- USB-C cable
- manual
- warranty papers

Some specs:
iFi micro iDSD Signature
Input range 16 - 32 bit / 44.1 - 384 kHz PCM, 352 - 768 kHz DXD, DSD64, DSD128, DSD256, DSD512, 88.2/96/176.4/192kHz MQA
Suitable headphones impedance 16 - 600 Ω
Output impedance < 1 Ω (without IEMatch)
Maximum output power 500 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 response N.D.
THD+N (@1 kHz) < 0.008%
SNR 115 dB
Crosstalk 79 dB

The signature is built well as with all ifi products care is taken to design something that will be a lasting a valued piece of equipment for years to come. The amount of controls are really impressive to me at least. I like the options and both front and rear IO doesn't disappoint.

I finished my review of the Diablo and was super impressed, I really wasn't expecting the signature to be this well rounded. That said it just checks all the right boxes for me, the IEmatch is one of the best implantations I've ever used, throwing at it my really sensitive all BA and lower ohm IEMs to find the worked exceptional. then finding normal mode was all I needed for the Fostex T50RP and other headphones. I was very pleased with the idsd ability to power everything high and low without a problem.
The Sound:
The idsd sig has a nice open and airy sound with that warmth I've come to like from ifi's Burr-Brown chips.
The Bass has details and texture it give a nice bottom end punch without over doing it. Bass boost or Xbass works well it might be one of the most useful Bass enhancers out of everything I have used , very tastefully done. the 3D works well too boosting the upper mids and lower highs to create a larger sound field.
Mids while warm have a great amount details to them, vocals are clean and filled with emotion and texture. Instruments have superb separation making this excellent for every kind of music.
Treble: Is far from harsh but maintains its details and sparkle, it is more neutral than bright and like the other frequencies is rich with micro details and a airy presentation.
Soundstage: Is naturally wide and imaging is very accurate with good separation.

Conclusion:
Battery life , build quality, sound and features make the iDSD signature the most well rounded portable or desktop DAC/ Amplifier I have used , its more than a jack off all trades as there is little if no trade off with its abilities.

iFi Micro iDSD Signature : Breaking All Barriers



Disclaimer:

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.

Introduction:

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:

https://ifi-audio.com/products/micro-idsd-signature/


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.

NOW LET'S TALK ABOUT THE SOUND PERFORMANCE....

Items used for this Review:

IEMs: 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....

The BASS:

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

The MIDS:

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 SOUNDSTAGE:

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.

Conclusion:

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.

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 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​

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.



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.



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​

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.



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.

Sound​

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.

Introduction

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.

Hardware

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.

Inputs/Outputs
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:


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.

DAC

Filters
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.

Firmware
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.

AMP

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.

xBass+
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.

3D+
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.

IEMatch
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.

Versatility
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.

Conclusion

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!

Micro iDSD Signature is the latest evolution of the iDSD series. Its predecessor Micro iDSD Black Label is widely regarded as a great device which contributed to building out on the expectaction regarding its evolution.

I did take my sweet time on this one as I’m particularly sensible to the topic. If one thing I learnt of this hobby is that source quality comes ages before drivers quality. I won’t anticipate the conclusions but in a nutshell Micro iDSD Signature is a remarkable player, sporting some great and even some unique features.

Physical endowment​

Infrastructure​

The device is easily transportable, but nowhere near to pocketable. Not really eligible if you are looking for a walker. Good as a sitter though.

Battery​

Micro iDSD Signature exclusively works from its internal battery, it never gets power from the USB VBUS bit.

This is good from the sound performances standpoint as while playing it relies solely on local battery generated power which is apriori less electrically dirty compared to the power coming from an uncontrolled host, or from a budget power supply unit.

On the other hand this means Micro iDSD Signature needs to be charged, and this happens from a separate USB port, a USB-C one.

The battery charging circuit is compatible with quick chargers and protected vs excessive voltage. Based on a direct interview I had with iFi tech people the maximum exploited charging amperage is 1.5A – whatever above that will not harm the unit, but will be wasted.

Next to the USB-C port dedicated to battery charging there is a tiny color-phased led: that is the sole visual indication informing us about the battery charge level.

Battery capacity is above decent. iFi declares circa 12h on Eco mode, 9h on Normal mode depending on load and volume of course. My experience matches such values, give or take.

Lastly, micro iDSD Signature has no “sleep” feature: if you leave it on while not playing batteries will go on discharging.

Inputs​

Micro iDSD Signature has no analog input. So unlike its predecessor Micro iDSD Black Label it can not be used as a standalone amplifier. Which is a pity, as the amp section is not bad at all as you’ll read later.

Two digital input are available: USB and S/PDIF.

The S/PDIF port accepts either 3.5mm coax or Tosink optical connections (a Toslink mini-plug adapter is supplied), but exclusively supports PCM only up to 192KHz sample rates.

The USB port is iFi’s “usual” recessed-USB-A-male connector (same as on Nano iDSD BL, Hip Dac, etc). Depending on firmware, up to PCM 768KHz / DSD512, in addition to MQA, are supported through this channel.

As mentioned above, the USB-A port is for data only and no power charging happens from this end. Which is good, as VBUS is usually a major source of electrical noise and therefore distortion.

The bad news though is that Micro iDSD Signature includes only limited, anyhow insufficient, “USB filtering” features. And it shows.

Ifi’s description talks about an “intelligent memory buffer” relying on a high precision internal clock. The presence of a (legacy) iPurifier circuitry inside is also in the specs. That said, I tested Micro iDSD Signature both natively plugged onto my PC and plugged through my Nano iUSB3.0 conditioner – and the output quality difference is significant. USB dejitter inside Micro iDSD Signature is sadly not something to write home about and this is bad when looking at its DAC module quality (more on this later) which does deserve a much better effort on this front.

My assessment has been conducted using Nano iUSB3.0 upstream. For your curiosity, here you can find some info on Nano iUSB3.0 and the general digital stream conditioning topic.

Outputs​

Micro iDSD Signature offers both 6.3mm and 4.4mm phone analog output, and 2xRCA line output.

The Line output works on fixed parameters: > 2V voltage, < 240 Ohm impedance, > 117dB (A) are the key declared values.

Phone outputs come with some very interesting modulation features such as the option to select 3 different amplification power levels (labelled Eco, Normal and Turbo mode), and engaging a built-in iEMatch circuit. Much more on these down below, in the Amp module section.

Very appealing is also the adoption of a full-analog volume control, technologically offering better quality compared to a (cheaper) digital volume modulation option.

Finally, Micro iDSD Signature offers 2 switchable sound shaping options called XBass+ and 3D+, which I again I will cover in better detail later below.

Power mode selection, iEMatch circuit, Xbass+ and 3D+ only apply to headphone outputs. All of these are totally uneffective on Line output.

Differently to what happens on most similar devices, Micro iDSD Signature provide exactly the same power levels either on its 6.3mm or on its 4.4mm phone out ports.

This is evidently not unrelated to the fact that both ports are actually linked to the same “S-Balanced” internal circuit.


I’m a strong supporter of the S-Balanced concept. So much so that I think iFi should dedicate more attention to it and better “close the loop” in terms of offering their users all the tools needed to fully exploit their technology. Let me explain.

For how hard I tried, I never found a 6.3 TRRS M connector available for purchase. Nor I would know where to buy a 4.4mm TRRS M to 3.5mm TRS F adapter, for that matter. iFi themselves do not offer any of such adapters on their options catalogue – and this is really odd to say the least.

Long story short, while and right because I understand the value of the S-Balanced option included on iFi Nano iDSD Black Label much better – where no 4.4mm nor 2.5mm native-balanced port is available – in the Micro iDSD Signature case I think no user possibly can take advantage of the connectivity flexibility opportunity, which will rest as an unexploited value.

So in daily practice the user will expoit Micro iDSD Signature’s balanced-ended and single-ended phone outputs “the old way”, “as if” they were a single-ended-only port (6.3) and a balanced-ended-only port (4.4).

Unlike what happens on most competition the user will get equal power from either port, and very similar cleannes too (the S-Balanced circuit behind Micro iDSD Signature’s 6.3 port will deliver uncommonly low crosstalk to single-ended loads as per design – you did read the whitepaper didnt you?).

The DAC module​

Firmware options​

Like most if not all other iFi DAC devices, Micro iDSD Signature can run a range of firmware variants, each offering specific features or optimisations. I find iFi’s approach of leaving the user free to choose amongst such different options a very welcome added value.

Firmware packages and the apps required to flash them are freely available on iFi’s web site, here. The flashing process is really easy and straightforward, at least on Windows platform (did not try on Mac).

The 3 significant versions to choose from for Micro iDSD Signature are:

I’m not much into DSD (I’ll explain why in a later article maybe) and I don’t de facto currently own nor plan to own music files sampled above 192KHz, so the two options which get my attention are 7.0 and 7.0c.

Their fundamental difference is one only but a significant one at that: with 7.0c iFi’s own GTO (Gibbs Transient Optimised) filter replaces Burr Brown’s native reconstruction filters.

I strongly recommend you read iFi’s whitepaper about why and how this may be technically desireable, or not.

Did you read the paper? C’mon do it! Seriously…

As you’ve seen the paper focuses on throughly illustrating GTO’s output features while leaving another important aspect in the background: with 7.0c Micro iDSD Signature will systematically upsample all digital input coming from the USB port up to 32 bit / 384KHz resolution prior to feeding the DAC chips. For what I seem to have understood this is fundamentally required for the GTO filter itself to work as intended.

It’s at this point worth noting (or remembering, for those who follow my articles) that I already experienced iFi’s GTO implementation in conjunction with Micro iDSD Signature’s smaller sibling, the Nano iDSD Black Label.

My full take on that is here, but in short: on Nano iDSD BL the GTO option “sounds worse” than the native ones – for my tastes at least. My suspect is in that case the upsampling effort ended up not adequately turned into higher sound quality delivery due to inherent dac bandwidth limitations.

DAC performances​

Micro iDSD Signature on firmware 7.0 offers very nice DAC performances.

Range is superbly extended, sub-bass is fully and correctly rendered, bass is bodied and especially phenomenally controlled, mids are present without exaggerations and trebles are powerful and vivid.

Particularly significant are cleanness, note separation, imaging and layering.

Directly compared to my reference DAC which is Apogee Groove (my take here), Micro iDSD Signature on firmware 7.0 has a deeper lowend extension on one side, a less extended treble span on the opposite side. Tonally it comes accross even more controlled than Groove on the bass (up to delivering a “leaner” flavour there), very similar on the mids and trebles. Draws on 3D space very, very well, although still not precisely at Groove level. On space rendering alone, Micro iDSD Signature is the single DAC that comes closer to Groove that I heard as of yet, and that’s saying quite something.

A very evident feature of Micro iDSD Signature DAC which is worth underlining is tight transients.

The “Bit Perfect” option is very tight. All notes are snappy, razor cut. Switching onto Minimum Phase or Standard transients get a tad more relaxed, less “dry”, yet the general impact stays way into “analythical” territory, especially when compared to a more “musical” alternative e.g. Apogee Groove.

In terms of transients rendering Micro iDSD Signature is actually more on Chord Mojo ballpark – for those who have experience with that. Mojo stays a bit ahead of Micro iDSD Signature on its unique capacity to close the gap between front and back instruments, however Micro iDSD Signature provides quite evidently better results in terms of extension, lack of coloration, and detail, and seriously beats Mojo on space rendering (which never was Mojo’s specialty, there’s that…).

With firmware 7.0c Micro iDSD Signature will upsample all digital traffic incoming from the USB line prior to passing it to its DAC chips.

While this does not produce any “dramatic” difference when the original samples come at an already high resolution (96, 176 or 192 KHz), an evident improvement is audible when 44.1 or 48KHz material is being supplied, and especially so of course if the track mastering is good.

The improvement is of course mainly on spatial reconstruction, size shaping and imaging.

Pulling back the comparison vs Apogee Groove, firmware 7.0c comes out as a major point of advantage for Micro iDSD Signature. Both DACs show great mastery beyond the 40KHz mark (where most of the information on space, reverberations etc come from) but that only is applicable if there actually is some digital data in that region to be decoded. On native 96KHz++ material the two DACs compete head-to-head. On lower sample rate material Micro iDSD Signature offers a built-in, automatic and very well implemented (!) upsampling option, while Groove has to rely on the same happening on the host (if ever.

Another interesting note: Micro iDSD Signature is very much able to exploit the GTO upsampling and convert it into a tangible benefit to the user when busy with sub-hires music at the very least, while the same does not happen on Nano iDSD Black Label. Why? I don’t know. I suspect this is either because the GTO algorithm is better implemented on fw 7.0c (usable on Micro iDSD Signature) vs fw 5.3c (usable on Nano iDSD BL), or because Nano’s lower-tier DAC section is unable to exploit the opportunity. Or both.

Another very important note to make about GTO is that it renders transients even tighter compared to the already tight Bit Perfect option on non-GTO 7.0 package. And, there’s no escape: when 7.0c is installed only one filter is available – no Minimum Phase or Standard alternatives are attainable. You better like it as is…

And simply put, I don’t. I find it excessive. I do appreciate of course clarity and cleanness, and precise rendering of each note – it’s a matter of “levels”. This is of course totally subjective. I have friends considering GTO’s reconstruction “supremely natural”. I’m afraid I can’t anticipate which one you will prefer.

One dufitul last note: I don’t use MQA, so I did not try / test Micro iDSD Signature’s proficiency on that. Not big loss for you as due to what I just wrote I honestly haven’t got any decent experience / opinion to offer on this topic, other than the trivial comments you can easily find everywhere and don’t certainly need me to paste here.

Summarising: Micro iDSD Signature offers very, very good DAC performances. Imaging and spatial drawing in particular are nothing short of spectacular. GTO firmware offers automatic well-executed upscaling to sub-hires audio tracks. Transients are rendered from quite to very tightly, which more musical-sounding presentation lovers might not like.

The AMP module​

As I quickly pointed out up above, Micro iDSD Signature offers some very interesting features when it comes to its internal amp section.

Firstly, its internal S-balanced architecture is equally available on both the 6.3 and 4.4 port, although for the reasons explained above in the real world scenario you can bet the two ports will be used as if the former was single-ended only, and the latter balanced-ended only. Too bad.

Secondly, and obviously related to the previous point, both ports provide the same output power levels – so choosing either is not a matter of power delivery, rather of convenience, and of a little cleaner output (better xtalk value) when a balanced connection is established on either port – so de facto on the 4.4 one for lack of avaialble 6.3 trrs connectivity options.

Finally, it allows for power level reconfiguration at the click of a switch to optimally supply high impedance cans – requiring as high voltage swings as possible – or low impedance and low sensitivity ones, like planars – requiring little voltage and very intense currents – or even IEMs. Three different “powering levels” are available, selectable with a switch on the device side, and a built-in IEMatch module is also available for added measure.

At the Normal power level – the intermediate one of the three total – Micro iDSD Signature outputs something short of 2W max power (a bit less than 1W RMS @ 32 Ohm) and 5,5V max swing. That’s already great power.

My Shure SRH1540 (46 Ohm 99dB, but much more current hungry than spec facevalues tell) are biased very satisfactorily on Normal level: bass is full while also staying very controlled, trebles are nicely sparkly – within the limits of a treble-polished driver like 1540 of course.

Indeed, switching iEMatch on makes the situation even better as it tames a further bit of the unneeded voltage swing, making bass come out futher controlled and cleaner. A real pleasure to hear. IEMatch High setting is already sufficient in this case, which is consistent with SRH1540 impedance being still significantly higher than IEMatch-H’s 2.5 Ohm output impedance.

Switching Micro iDSD Signature to Turbo is not a good choice for SRH1540 – and that’s perfectly in line with logic too. The effect of excessive voltage swing on a low impedance load like that is similar to a taxing “Super High Gain” option: dynamics get closed-in, range is compressed, highmids get glary and expecially midbass goes too bloomy.

Same situation takes place with Koss KPH30i (60 Ohm 101 dB). Best biasing is obtained from Normal power + IEMatch-High. Eco power makes them sound muddy(er). Turbo power is totally excessive, KPH30i presentation gets unnatural.

As those who follow my articles probably already know, I’m not into high impedance cans, nor into extremely power hungry planars so I won’t comment on how the Turbo option does in those cases. Suffice here to say that Turbo setting promises 10V max and a tad more than 4W max power (1.5W RMS @ 64 Ohm), not peanuts at all for a portable device and many budget desktop ones either!

On the opposite end of the spectrum, I must stand and vigorously clap hands at how iFi solved the IEM equation instead: the combined benefits of the Eco power option and the built-in IEMatch module are nothing short of spectacular.

As all technically aware audiophiles know, IEMs despise high voltage and most times high power altogether. Impedances below 32 ohms – sometimes as low as 8 Ohm or less – like those on IEMs require (require, not simply prefer) low voltage swings, which is the exact opposite of what a voltage modulation amp powerful enough to drive higher impedance headphones is designed for.

When up to driving IEMs the very first thing to do on Micro iDSD Signature is to set the power switch to Eco setting. This makes sure the maximum delivered voltage is limited to 2V, and the maximum power is 500mW on an 8 Ohm load, which is way more than 99.9% of IEMs out there requires.

All of my IEMs are in facts perfectly driven by Micro iDSD Signature, on Eco mode and – on a case by case basis – with IEMatch set to Ultra or High. Same for my final Sonorous-II (16 Ohm 105 dB) which are closedback overears electrically behaving very much like IEMs: the best setup for them is Eco, with IEMatch turned off, although Normal + IEMatch Ultra is also a strong contender.


Micro iDSD Signature already comes with a number of features making some of its IEMatch built-in circuitry redundant, read useless: I’m talking about very low output impedance, support for loads as low as 8 Ohm and a volume pot in the analog-domain. That said, the IEMatch module stays beneficial to 2 main purposes: further reduce output voltage swing, and eliminate sibilance on hyper-sensitive IEMs.

The former of the two benefits is especially intriguing: on a case by case basis some drivers do sound better under Eco power other sound better under Normal power with IEMatch Ultra switched on on top. And for some others… it’s hard to tell – e.g. final Sonorous-II, Tanchjim Darling, final E5000.

Mind you: from a purely technological standpoint the topic is arguable upon to say the least. Post-attenuation does come with benefits and drawbacks like, I guess, everything else in life. The information I want to convey here is not how exactly I recommend to set Micro iDSD Signature to work best with this or that IEM, rather that the device offers the flexibility to try different ways to that target.

A truly multipurpose amp – finally!​

As I mentioned before, to my knowdge at least there’s no single amp implementation out there yet which is capable of feeding different impedance/sentivity drivers with equally optimal results. And to my understanding, there’s a solid technological reason for this : high impedance cans “sound better” when submitted to high voltage swings, low impedance HPs and IEMs distort in the same condition. Simple as that.

Conceptually we have 3 possibilities then:

1. Use different amps for the various cases.
2. Use a high voltage amp, and aposteriori cut its output voltage down. That’s where attenuators e.g. IEMatch may help.
3. Use a sort of “configurable” amp…

Micro iDSD Signature’s amp can be reconfigured to optimally support very high impedance cans (Turbo mode) or low sensitivity cans (Normal mode) or low impedance + high sensitivity IEMs (Eco mode) offering each category its own best welcome powering profile.

When facing low impedance loads, in addition to selecting Eco power mode there may still be need to engage the built-in IEMatch module to furtherly reduce output voltage, which will benefit current delivery to particularly sensitive drivers, and/or cancel some hiss out of the most sensitive of those.

Of course a curious question as this point might be “which of the two features should I preferably use before the other: Eco power mode, apriori limitating voltage swing, or IEMatch, cutting it down aposteriori” ? I had my own opinion on that already but I asked iFi’s designers’ take on this.

With regards to Turbo/Normal/Eco modes vis-a-vis headphone matching, our AMR audio background means that we are of the opinion that while the impedance of a headphone is a factor to consider in matching, the over-arching one is actually power > sensitivity.
This is why we developed the headphone calculator which takes the power output of a headphone amplifier and compares it to the headphones to be used. The resulting volume level will give the customer the best insight into the ‘matching’. Just like a 1,000W Mark Levinson would be a poor match for high-sensitivity horns rated at 110dB sensitivity. Or a 10W 300B SET would not drive 87dB Magicos.

Click to expand...

iFi’s headphone calculator is indeed an informative but most of all educative tool. Playing with it we can find out how wrong are common assumptions about this or that driver (IEMs or Headphones alike) requiring “high power”…

I can’t stress enough how brilliant I find iFi’s choice to equip Micro iDSD Signature with what it takes to allow the user to substantially change its amping behaviour to cope with the dramatically diversified nature of those drivers out there. A really, really welcome idea, and a unique one in the mid-tier segment this device partakes into at the very least, but to my knowledge in the one above too.

Sound shaping addons​

Similar to what is also offered on other iFi devices, Micro iDSD Signature’s amp section features two optional circuits providing bass enhancement and imaging improvement at the flick of a switch.

Both features are according to iFi’s documentation entirely implemented in the analog domain. No DSPs are involved which promises the minimal impact on sound quality of course.

“XBass+” behaves like what an EQ expert would call a low shelf positive filter. By ear I would say it pushes lows up by 2dB-ish from 100Hz down. Very personally speaking, I don’t like these types of options in principle – irregardless of their implementation quality that is – my fundamental position being: if I want more bass than the one delivered by the driver I’m using right now… I swap on a different driver. In the special Micro iDSD Signature case, XBass+ may be actually welcome to “compensate” the device super-lean bass presentation, especially as delivered by the GTO filter (fw 7.0c).

“3D+” is a “crossfeed filter”, i.e. a function that puts “some” of the right channel output into the left one and viceversa, simulating on headphones what happens when listening to loudspeakers. Within its limits (it’s not parametric, configurable etc – just a mere on/off) and situationality (effects are totally evident on some tracks, minimal on others) the trick is really nice, and I used it quite often. My main application case are those original jazz masters from the 60ies where mixing tended to be executed by hard panning each instrument on a single channel only: 3D+ sounds almost magical in those cases.

Conclusions and evaluations​

Well, I’m certainly not known for generosity when it comes to assign good scores. This time I must say that from the technical standpoint Micro iDSD Signature deserves a very high remark.

DAC reconstruction quality on high-res lossless material is at the absolute top I found below 1K$ and possibly above. The sole other devices who can play an even match with Micro iDSD Signature on this part are Apogee Groove and Questyle QP1R, all the rest being a full class below at the very least. My experience is not oceanwide, so there may be others of course, but still....

Not only: adopting firmware 7.0c Micro iDSD Signature automatically upsamples all USB input thereby granting a significant share of the same quality to sub-highres tracks. Upsampling is not black art, it is very possible to implement that on the host, and feed competing DACs with the same improved input, and obtain improved output from those too – but it must be done, and done right, which is an extra burden and cost, while Micro iDSD Signature does it “out of the box”, and does it right too, and this is a major value on my scorebook.

Micro iDSD Signature’s DAC is so good that a no brainer rec is to exploit the Line Out option and interconnect into a serious quality desktop amp any time that’s possible (nothing short of a Jotunheim-2 at the very least will make Micro iDSD Signature’s DAC decent justice), but mobile DAC+AMP standalone operation will not disfigure at all when compared to no matter which top alternative device in its same price class.

Always talking about standalone mobile features, Micro iDSD Signature’s ability to reconfigure its amping section on the fly to optimally cope with IEMs, or low impedance cans, or high impedance hps, or “nasty” planars is totally brilliant, and deserves – that alone – a standing ovation for the idea, and the implementation quality too.

As always where there’s light there’s shadow too.
The DAC section is so good that the lack of adequate built-in USB dejitter becomes very evident, and frankly I find it almost disappointing.
On an even more subjective level, all filters in general and the GTO filter in particular deliver extremely tight transients – some may find them “more natural”, I find the opposite.

Last but not least, the price – and the value.
At € 699,00 EU list price Micro iDSD Signature is not an inexpensive device.
And please add another € 50 at the very least (iSilencer) or better another € 150 (iPurifier3) to add some improved USB cleansing.

Is it worth it?

Well, evaluating it in terms of a truly mobile (if not pocketable) device, not relying on host batteries, offering top class DAC competence, and truly capable to optimally bias anything, from the “easiest” IEM up to the “nastiest” planar overear well… Micro iDSD Signature is an easy win.

Such consideration does not make its price tag cheaper of course, but finding another battery driven device with similar output quality at a significantly lower price – at least to my knowledge – is today a hard task.

Totally different is of course the perspective if we plan a mainly static, “desktop” application. In such case Micro iDSD Signature stays a very significant device, but the price of its unexploited portions would make its convenience score poorer.

Disclaimers​

This Micro iDSD Signature device has been provided as a temporary loaner unit by iFi for the sole purpose of my assessment.
This article is also published here.

Ifi micro signature

Very neutral and flat sound signature (especially compared to zen can and hip dac ) reminds me of a good THX amp ( not weak on bass or sterile ) does not color sound at all that I could hear
Good technicalities, dynamics and punch
Excellent build quality and looks
6.3 and 4.4 both offer full power , balanced or single ended
( don’t have to use balanced cable )

4,100 mW output at 16 Ω
Balanced output through 4.4 mm jack 6.3 offers single ended but same exact power output
Transportable vs Portable ( it is kinda big and heavy, fits in bag and on a desk but not in pocket really )

500 mW (8 Ω, Eco mode)
1,900 mW (16 Ω, Normal mode)
4, mW (16 Ω, Turbo mode)
1,560 mW (64 Ω, Turbo mode)
166 mW (600 Ω, Turbo mode
Output impedance is less than 1 ohm with iem match disabled
Supports MQA out of the box
Front panel Status Led has 7 different colors that will light up.
Magenta is MQA, and red indicates DSD512.
The volume dial also acts as an on/off switch. Feels great and is responsive, again quality.

Front panel also includes XBass and 3D mode. Along with a built-in IEMatch,on the side which allows sensitive IEMs to be used without hiss and 3 power modes. ( ECO, NORMAL, TURBO)
These offer more power and thus drain the battery at corresponding levels. A digital filter switch is also included, but this has no function with the current firmware.
3D Mode tends to brighten the sound to my ears and could be a use on certain pairs to enhance treble.
Xbass (as always with ifi) is the best bass boost I’ve ever heard but I do not use it most of the time ( works great on p1 and heart mirror )

On the back of the Signature is a S/PDIF 3.5mm coaxial input for the Toslink mini-plug connection. RCA output and a USB 3.0 type A input port. Works with android and IOS with the correct cables

Included in box
6,35mm jack adapter, USB OTG cable, adapter OTG – USB-B, two rubber bands, optical adapter, RCA cables, soft pouch, and 10cm USB-C cable

4-10 hours of battery life depending on usage, power level and volume used.

Cons

Audible pop noise when turning on and off ( didn’t have to be necessary imo )
Is kinda hard to tell what level the battery is at.
Its kinda expensive but replaces most my desktop amps.

This is a one of a kind on the market, nothing else like it.
It’s awesome.

iFi sent me the Micro iDSD Signature, without any prerequisites, for review.

I've long been curious about the Black Label series of portable iFi DAC/amps, given their popularity. Quite a few people have wanted me to review them as well, so when iFi offered me the Micro iDSD Signature, the last, limited edition release of the range, I jumped on the chance.

Hardware



Externally, the iDSD Signature comes across more as "transportable" than portable, being larger than even Chord's Mojo/Poly combination. Adding to this is the range of inputs and outputs, the front 6.3mm (1/4") socket being the most prominent on the front, and the RCA jacks likewise on the back.

With the Signature, a 4.4mm Pentaconn port is added. While the iDSD Signature doesn't use a balanced circuit internally, this means that you don't need to use the 4.4mm socket to get full power out of the device. The 6.3mm socket will do just fine for that.



Except for the USB-C power socket on the side, iFi has yet to move away from their strange, if cleverly logical use of a full-size USB-A plug as the main input. While initially odd, it makes sense when you see the included USB 3 extension cable in the box, chosen for its better shielding (the input is only USB 2).

Unlike the previous Black Label version, the 3.5mm input on the front is no longer available. Only digital input is possible.



If you decided to do an old-school "stack" of phone or DAP with the iDSD Signature, then all you need is a USB-C or Lightning to USB-A socket adaptor, both readily available. Not to mention, a USB-A plug-socket is more reliable than a USB-C one, in my experience.

If USB is not preferred, a combo 3.5mm S/PDIF and mini-optical jack is included, though the high-res support is somewhat more limited with these.

Speaking of which, the highest input resolutions of DSD512 and PCM768 are only available if you downgrade the firmware to 5.2, and eliminate MQA. Given that these are unicorn formats, and up-sampling to that level will add no benefit above the DSD256 and PCM384 limit with the stock firmware, the point is rather moot.

Features

One of the keys to iFi's popularity has been their inclusion of features such as the XBass and 3D modes in their products. Along with a built-in IEMatch, allowing sensitive IEMs to be used without hiss, and 3 power modes. A digital filter switch is also included, but this has no function with the current firmware, and, like the ultra-high-res input, only works if you downgrade the firmware to the non-MQA version.

The XBass feature adds a nice, but not excessive amount of bass, filling in things nicely with headphones that are more neutral in tuning, such as the Final D8000 Pro, which I used with the iDSD Signature.

The 3D mode, on the contrary, has the perceptive effect of brightening the music, even though it uses crossfade and doesn't change the frequency response, making it sound more open. Combined, you get something of a v-shaped sound, which can be good if you're like me and listen to a wide variety of music, and tweaking the sound in this way can make genres that are less compatible with one's headphones more enjoyable.



The three gain modes, labelled Eco, Normal and Turbo, allow one to trade battery life for power, or provide a better range of volume adjustment for one's headphones or IEMs.

Of that, the volume control is one of the negatives of the iDSD Signature. Including the power switch, it has serious channel imbalance until you get to about 10 o'clock on the dial, leaving little over 180 degrees of movement for volume adjustment, a fair bit less than if a separate power switch had been used.

The other, main negative, is a lack of any indication of battery level. While it's readily possible to get up to 8 hours, or possibly more, of listening time, not knowing when one is about to run out of battery can be a bit frustrating. The only indication of anything power-related is a light showing that the unit is charging next to the power input USB port.

In Use

I usually start with IEMs when testing a portable device, and so I brought out the 2020 Campfire Andromedas to do my regular hiss test. Even with the unit at full volume in Turbo mode with the IEMatch off, the blood running through my head was louder than the minute amount of hiss that was audible, and the IEMatch cut even that! A great pass there.

Powering the Andromedas, while a couple of Ohms output impedance doesn't usually change their sound signature, the IEMatch seemed to drop the bass a bit in the first "High" mode, with it coming back more somewhat in "Ultra" mode.

This was mildly regrettable, as there isn't much volume range to begin with in Eco mode, and the IEMatch allowed the volume knob to be adjusted to a more useful position with the Andromedas.

Listening impressions

I had the Neo iDSD here at the same time, which provided an interesting, and quite dramatic contrast.. Unlike the Neo iDSD, the iDSD Signature is quite warm and engaging, with a stronger sense of bass presence than even the Chord Mojo, which is slightly on the "warm" side of things. While not providing quite the sense of sharp relief that the Mojo does with good acoustic recordings, the iDSD Signature gives the sound more body, even as a DAC, and makes for very engaging listening.

Full-sized headphone drive is very good for a portable device, with a generally clear and punchy sound, even with the high-end planars I have here, such as the Final D8000 Pro and Meze Empyrean. The results aren't as good as using a dedicated headphone amp, such as the Schiit Jotunheim, which is on another level altogether. However, sans comparisons, the enjoyment factor is very high with the iDSD Signature.

In the world of portable audio, there are always sacrifices at any price point. Want a conveniently device? You'll sacrifice power and/or battery life. Want functionality? Fidelity may be the sacrifice instead. With the iDSD Signature you get plenty of headphone-driving power and work-day battery life, but you need a transport, such as a phone, DAP or computer to use with it, and it's not readily pocketable.

Likewise, rather than the sharper fidelity and wireless convenience of a Mojo/Poly combination, you get an optional bass boost and 3D mode. This is where the iDSD Signature succeeds, in making the music enjoyable, even if not delivering absolutely the most fidelity available as you can get from something like a Hugo 2 or desktop rig.

The D8000 Pro is tuned towards "neutral", which can make it less entertaining to listen to some music with. Yet, engaging the XBass brings a pleasant boost when some more warmth benefits it, giving the headphones a character more like the Empyreans.

Likewise, I tried the iDSD Signature as a DAC into the ALO Audio Studio Six and Audio-gd Master 9 with good results, the sense of warmth and engagement coming through strongly, adding a sense of joy in combination with the better amplification.

Conclusion

I've enjoyed my experience with the iFi iDSD Signature. I understand now why the Black Label version was so popular. Providing plenty of power for full-sized headphones, yet almost complete silence even with sensitive IEMs, the iFi Nano iDSD Signature has a punchy, warm and engaging sound that makes it a joy to listen with, and options to bring out a bit more entertainment from the music.

iFi iDSD Signature is the newest transportable DAC made by iFi. It pushes 4W of power into the headphone output, decodes MQA, and it is priced at 649$.

Sound quality for the price
Rating: 8.5 out of 10.

Build quality
Rating: 8.5 out of 10.

Value
Rating: 8.5 out of 10.


Packaging

Long list, but short USB-C cable.

iDSD Signature, same as the iDSD Neo, has refreshed design of the box. It is grey with the Signature’s photo on the front.
Inside you will find a long list of useful accessories:
6,35mm jack adapter, USB OTG cable, adapter OTG – USB-B, two rubber bands, optical adapter, RCA cables, soft pouch, and 10cm USB-C cable.
As always, it is packed inside in smaller cardboard boxes.

Build quality

This new color is gorgeous.

iFi again shows how it cares about the details and build quality, but there’s one thing that could be better. It is almost the same as iDSD Micro Black Label but in the new navy blue color, which looks definitely better in real than on the renders. iFi also removed some switches on the device, but that doesn’t change much at all.

Beginning with the front, you will find the 6,35mm jack output and the 4,4mm one. iFi cut the 3,5mm analog input. The next thing is a pretty huge LED indicator that shows the quality of the files. It is matte and quite dark, but I don’t have any problems recognizing the color in the daylight. Thanks to the low brightness, it also doesn’t light up the whole room during nighttime. Going further, two switches – XBass mode and 3D. I’ll talk about them more in the next paragraph, here I can say they’re delicately too small for me, sometimes I have to try a few times to change their position. The last thing placed on the front is the potentiometer, which also turns on the iDSD Signature. It isn’t the best I’ve ever used. After turning for about 30 degrees, it starts playing, but with disbalance – only the left channel is working. I have to rotate it for another 10 degrees for the right channel to begin working. After that, it is working linear, but the first step isn’t encouraging.

On the right side, there is only a USB-C connector for charging. It is placed pretty deep, I have problems with some cables to work correctly, and the attached cable is too short to charge it comfortably.
The left side is equipped with three sliders, the same you can find on iDSD Micro BL – power mode, digital filter, and the iEMatch.
On the rear there are placed USB Type-A, SPDIF input, and RCA outputs.

I’m missing the 3,5mm jack input.

Functionality

Those logos of used technologies are a nice addition.

iFi is a company that loves to put new technology into its devices, and it isn’t different this time.
As the first, but an obvious thing, MQA decoding for Tidal Master Quality files. The second thing that is definitely worth to be mentioned is S-Balanced output circuitry. It means that Signature delivers improved sound quality, usually reserved only for balanced output, within both outputs, even the single-ended one. It cuts crosstalk and distortions in half based on the iFi’s words.
The functionality behind the two front switches, which were also in iDSD Micro BL, was hardly improved. XBass function works way better than ever. It isn’t only a loudness. It truly warms the whole sound, without any echo feeling.
The 3D function is also useful in the music when in the iDSD Micro BL, I would use that only for games or movies. It doesn’t work such strikingly in iDSD Signature, but it is way more accurate. It is hard to get used to it in one minute, but after some time, in my case, after about one hour, it began being useful also in gaming.
On the left side, you can see three switches that work in the same way as in iDSD Micro BL. Power Mode, which is similar to the gain, iEMatch to use the Signature with low impedance IEMs, and the filter – Bit-Perfect, Minimal Phase, and Standard. It is basically from the sharpest to the most natural.
Battery life is also great at about 12 hours.

Sound

Maybe the color is more saturated, but the sound is flatter.

It is time for the essential part of every audio device, the sound. iFi iDSD Signature is a pretty nice upgrade compared to iDSD BL. It has the same sound signature, so it is natural to neutral (depends on the filter), wide soundstage, great holography, but it is different in one thing. iDSD Micro BL isn’t imposing much from itself, and it lets your cans sound just how they are meant to. The new Signature came up a little less saturated, more technical, keeping the headphone of choice a little bit tempered down.

The bass isn’t the party king. It isn’t much saturated, but really flexible. It doesn’t matter if you prefer the speedy bass or the sloppy one, iFi provides both of them. If you prefer the juicy bass just turn on the xBass option, it will be closer to the Neo bass, but with extra weight.
Lows aren’t as highly textured as I like, but I love how they disappear after the strike—just boom and silence, but only when it has to. In the other situation, it can be slower but never gets muddy. It all depends on the mix and the song. In two words, this bass is clear, tight, speedy, and very flexible.

The midrange has delicately more life than the bass, but it isn’t on the iDSD Neo level. It is pretty smooth with female voices and provides a lot of air with excellent separation, which can be really surprising. The midrange doesn’t have any charming feeling, more like the natural flat. Lower vocals are nicely textured, without dryness. For me, it is the best part to get focused on. Even the awful recordings of Rammstein provides fantastic impressions after listening to the Till Lindemann voice.
As I mentioned above, the Signature doesn’t impose almost anything, but it doesn’t get way too technical and transparent.

It’s just very detailed, very accurate, and correct.

I think the “Signature” is a wrong name for the new iDSD as long as it doesn’t really have its own sound signature.

The treble is spot on, again. Not sharp, not smooth, just natural with lovely sparkles and click. All wind instruments, drum plates, or even some triangles have a full body. There’s no feeling of emptiness at any point. Click is awesome in the calm, slow songs where it behaves like the bass. Clicks and disappears in the black background.
All the sparkles are pretty calm, without any chance to sibilance.
My favorite song for the treble last time is “Pristine” by Snail Mail and it sounds wonderful also here. Listening to this pretty bright song, with pretty bright Craft Ears Four doesn’t cause pain, it pleases my ears for long hours.

The soundstage is very similar to the Micro BL overall but is broader and more profound. Also, the height is way better, it can go way higher and lower compared to iDSD Micro BL. The Signature’s soundstage is definite, without any false markings around. It doesn’t fly around with many sound sources changing their place to make the listener immerse himself in the performance. All sound sources are holding their positions, which is also great, just different.

As I mentioned in the “Technical” paragraph, the 3D function is great in gaming, but you have to get used to it. The iDSD Signature didn’t trick me even once, letting me play peacefully with a trusted sound source.

Different products, different playstyles.

Short comparison to the iDSD Neo
iFi iDSD Neo and iFi iDSD Signature are absolutely different devices.
The newest stationary iFi DAC provides a lot more fun, saturation, and it is vibrant. The iDSD Signature is more technical and flat. The Signature has more body in some situations, with heavier sound overall. Neo has a more innocent playstyle. It is like comparing the strict father and the one that prefers a stress-free upbringing.
The soundstage is similar in terms of width and depth, but as I mentioned above. The Signature is more spot-on when the Neo gives a lot of magic, and it just swims around.
I’ll go once again with a comparison, Signature is like the F1 race, where everything has to be in place, and the Neo is like free-roam with friends at night, where you can ride how you like to.

Summary

Changes aren’t big, but it is a fantastic device.

The iFi iDSD Signature is a great successor of the iDSD Micro Black Label, but it isn’t a revolution. It provides better features, micro details, and the soundstage but overall doesn’t kill its predecessor. It is a totally different device compared to the iDSD Neo. Still, it is definitely a great refreshment that provides very high SQ with flattened natural sound signature, wide, high, and profound soundstage, but without much juiciness and vibrance. It isn’t a sound signature for everybody, but it is great if you’re looking for a flat sounding device.



Gear used during this review for the sake of comparison and as an accompanying equipment:

• Headphones – Philips Fidelio X2HR, Kennerton Odin, Vision Ears EVE2020, Audeze LCD-3, Bqeyz Spring 2, Craft Ears Four, Hifiman HE400i 2020,
• Sources– Topping DX7 Pro, SMSL M300+SP200, Chord Mojo, iFi iDSD Neo, Topping DX3 Pro, EarMen TR-Amp