Pros: Plus sound quality, copious amounts of power, fantastic finesse, plays power hungry cans all the way down to sensitive IEMs with no hiss, supremely flexible, true fixed line-out, XBass and 3D+ not necessary for best sound anymore—they are truly optional augmentations, MQA compatible, improved aesthetics over Micro iDSD BL, solid construction

Cons: transportable not really portable, channel imbalance at bottom quarter in the volume knob (easily fixed with changing power and IEMatch settings), treble loses some detail to blending (cymbals etc.), mids a hint dry and forward, forward mids reduce dynamic movement of vocals, some artificial depth increase in the soundstage

List Price: £699

Acknowledgment   

I’d like to thank iFi for loaning me the Micro iDSD Signature. I have received no compensation for this review and the insights are my own.

Introduction

Anyone who’s been following me for a while knows that I’ve reviewed two full sheds of iFi gear. This one makes eight after the following: iFi Micro iDSD Black Label, iPurifier2.0, iDAC2, iCAN SE, Micro iUSB3.0, iFi IEMatch 2.5, and iFi DC iPurifier2. I’ve also spent some time with the original iDSD and the original iCAN. I hope to keep working with iFi as they are a fantastic company full of great people.

Useability: Form & Function

Unboxing

The unboxing experience is basically identical to the Micro iDSD BL married with the Nano iDSD BL (more details in those revieww). TLDR; it’s not particularly pretty, but you get a lot of stuff in the box; all the things you need to hook up to a computer. It’s still missing a USB-OTG cable. Feel free to buy iFi’s very well built and high compatibility USB-OTG. I’ve used multiple USB-OTG cables and adapters and they are not all plug and play as you’d expect them to be. The iFi USB-OTG is plug and play, it worked with every device I tried. No they don’t include an apple camera connect kit either. Jibbers Crabst help you if you are running with an Apple device as your source; they’ll rob you blind.

Aesthetics and ergonomics

The major ergonomics critique of the iFi Micro series is that calling them portable is a bit of a joke. They are portable like your laptop and less convenient to carry, as the bag that works for iFi’s unique signature shape has only just been made by iFi (link to thread). I loved the iFi Micro iDSD Black Label, but it was about as transportable and ergonomic as a pet brick. Don’t throw your Black Label, it’s so much better than Father Jack’s brick. It’s a shape that grows on you. Love who your Micro be, iFi.

From an ergonomics perspective the new Signature is smoother, sleeker, with more attractive printing and a more durable frame than the Micro iDSD Signature. I say more durable for a different reason than one might think. It is made of the same aluminum, it has the same anodized finish (albeit in blue), but it has some key differences. The Micro iDSD Signature adopted the improvements in design made by the Nano iDSD BL by having chamfered edges, in addition to this it also replaced the large metal switches of the Micro iDSD BL with small plastic switches that are harder to hit while adjusting the volume and impossible to snag when plugging in any inputs or outputs. The Signature has lost the Micro iDSD BL’s 3.5mm analog input and moved all inputs to the back of the unit. This will be a welcome change for most, but it does prevent people using the Micro iDSD Signature as strictly a headphone amplifier. I’m not mourning the loss. The font on the bottom of the enclosure is just slightly more legible than the BL. Please do better on this iFi.

Build quality

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The iFi Micro iDSD Signature has a lot of things embedded in its case: 5 plastic switches in two types, 2 headphone outputs, a mini-SPDIF/coaxial digital port, a USB Type-A male jack, and RCA line-out. Not all of them are perfectly centered in their slots, but this is a minor cosmetic thing—the tolerances are fine. When using a 4.4mm male to 2.5mm female adapter from Cayin and 4.4mm cables from Campfire, I did experience some sensitivity to depth of placement in the 4.4mm jack. Sometimes I would lose the left channel if not placed perfectly and would have to pull the 4.4mm plug out of the slot a little, which was unexpected. This probably tells me that pushing too far in makes the left channel hit the divider or the L- in the diagram below.

Features and functionality

The iFi Micro iDSD Signature is chock full of features:

• plays well with all kinds of headphones and IEMs,
• built in analogue tuning effects for more bass (tastefully done) and more treble (also tastefully done) reminiscent of Micro iDSD BL
• the magic hiss-busting of iEMatch built in (review of iEMatch2.5 here)
• iPurifier built into the USB
• separate power and signal USB inputs (this matters)
• extreme format compatibility with nice indicator lights (green PCM up to 96kHz, yellow PCM to 176-384kHz, white PCM 768kHz, cyan DSD up to DSD128, blue DSD256, red DSD512, magenta MQA)
• and loads of power for demanding cans and IEMs
• USB-C charging
• iFi’s proprietary S-Balanced circuit; designed to get closer to balanced sound out of single ended outputs. Here’s what iFi says about the tech: “Both headphone outputs utilise our ‘S-Balanced’ output circuitry. This delivers the sonic benefits of balanced connections with all headphone/earphone types – even those with single-ended connectors – cutting crosstalk and associated distortion in half.” If you want to read more, see their Tech Note press release.

I love that the Swiss Army knife tradition of the Micro iDSD BL has been continued. The Micro iDSD line-up are still the most versatile amp in terms of headphones and IEMs you can hook up to them and have them play nice. The output didn’t hiss with the Campfire Ara or Solaris LE when set to the right level, but I did use IEM match set on the lowest available setting (high) to get a little more play in the volume knob. The Unique Melody Mason v3, which hisses on some sources was silent on Eco mode and got plenty out of the volume knob to not need to engage iEMatch (sounds fabulous as usual).

Power Output

Turbo (8.0V max/4,000 mW @ 16 Ohm) Normal (4.0V/1,000 mW @ 16 Ohm) Eco (2.0V/250mW@16 Ohm)

To exactly the same as the iDSD BL, so to be honest; I’m not sure what to tell you with regard to what to buy while there are still Micro iDSD BL on sale in the wild. I don’t know if there was a silent revision on the Micro iDSD BL, the site is in error, or they just found a way to get more power out of the same amplification. I’m really wishing I had both in house now. Stats on the website for both Micro iDSD BL and Micro iDSD Signature now read as this:

Headphone out
Turbo Mode	Power (max)                      10.0V/4,100 mW (back-calculates to 24Ω resistance) Power (continuous)         >1,560 mW @ 64Ω; >166 mW @ 600Ω
Normal Mode	Power (max)                      5.5V/1,900 mW Power (continuous)         >100 mW @ 300Ω; >950 mW @ 32 Ω
Eco Mode	Power (max)                      2.0V/500 mW @ 8Ω Power (continuous)         >250 mW @ 16Ω

Two features that the Micro iDSD BL has that the iDSD Signature has lost are analog input (headphone amp only mode), and digital output (for connecting to Sonos, etc.). Most people will use the Micro iDSD Signature as a DAC/Amp with their phone, and won’t be looking to have a separate DAC, but for the folks who want to use their high end DAP, but with a more robust and more flexible output stage, your DAP will just be a transport as you’ll need to bypass the DAC function of your DAP, if you even can. This makes the iDSD Signature less flexible than the previous Black Label line. It can still function as a DAC only, but you shouldn’t buy it just to be used as a DAC. The iFi Nano iDSD BL performs identically as a DAC only in my living room speaker tests to the iDSD Signature. Both the Nano iDSD BL and this also run with MQA and when you do MQA you are limited to DSD256 and DXD. If you don’t care about MQA you can get a different firmware that allows DSD512 and double rate DXD. My personal opinion on DSD512 is that it offers no detectable sonic benefits for double the storage space of DSD256. The science behind it backs up this conclusion, DSD256 already moves DSD noise shaping into inaudible ranges. I think MQA is a better option, personally, especially if you are a Tidal streamer. My Nano iDSD BL review does some testing on this and is worth giving a read if you want more discussion of the MQA feature of this DAC/Amp. I’m not going to repeat myself here. Also, MQA may be the most controversial audio format ever, for lots of reasons. Darko Audio has addressed loads of MQA stuff on his blog; it’s well worth a read.

Given the price of portable amps that can output the kind of juice that the iDSD Signature outputs, it would have been nice to include an input. Personally, I would have forgone the RCA output and had a 4.4mm input and a 4.4mm balanced output; but I understand why they didn’t do this. Providing an adapter that allows using single ended outputs could result in people trying to use single ended inputs with the same adapter and damaging the device and whatever it is connected to. It’s a relationship that is just asking for disaster.

It’s a little disappointing that the iDSD Signature doesn’t included a true balanced circuit, as both the Hip DAC and the iDSD Diablo are true balanced. I understand that to hit a price point and size for the features there have to be trade-offs. Both their true balanced portables lack iEMatch (though this can be added via an external iEMatch), and lack 3D+ (the Hip DAC has xBass, while the Diablo lacks this). The Hip Dac is available at $149, while the Diablo will set you back $899. The Diablo is $200 more than the Signature, but it comes with a $50.00 case designed for iFi gear, true balanced head and line outputs, and a 4.4mm to dual XLR balanced output cable. Word on the street is that the iDSD Diablo has a colder, sharper reference tuning, so the power difference isn’t the only difference, but the power difference may matter with some headphones. For reference, if I use Owenduffy.nets convertor, I get 9.9 watts into 16Ω as the Diablo’s max output (using 12.6V RMS and 16Ω load). The output will be less than that, but that tells you how much comparative energy the Diablo has with its power level vs. the 10 volts on the Micro iDSD Signature (6150 mW into a 16Ω load, mathematical conversion, not actual performance). Unfortunately, I’ll not be able to get both the Signature and Diablo in house unless I buy both. I’m not made of money, and if I were made of money spending that money might be deadly.

Here are some things I didn’t test:

• Battery life. I used this mostly as a desktop setup, and I’ve had it plugged in via it’s nice little USB-C power plug for a month at least. The battery hates me right now. During this pandemic there hasn’t been a whole lot of cause to throw this on a desk in an office. I got ten hours with the Micro iDSD BL in my usage, I would expect this to be identical. It does have a cool battery level indicator feature: white >75%, green >25%, red >10%, red flashing ≤10%.
• Ultra Sensitivity iEMatch setting. In my experience nothing needs this. I only use it to give more volume play when I have amplification mismatches. The multiple amplification settings obviate the need for the Ultra Sensitivity setting most of the time.
• The filters. I’ve always preferred iFi’s Bit Perfect setting (which confers Extreme DSD setting and Bit Perfect DXD setting at the same time), no need to go messing with it. My past experience was that smoothness and warmth were increased at the cost of fidelity using the other settings.
• MQA, see iFi Nano iDSD BL review for more on that.

It’s about time for some listening notes.

Audio quality

As noted earlier, I don’t have the original Micro iDSD BL in house, only the Nano iDSD BL. I put the iDSD Signature in my living room setup feeding into my amp and speakers (no need for names) as a DAC only and compared against the Nano iDSD BL. They sounded exactly the same to me on the setup. If there are differences, they can’t be detected with a modest 2-channel setup. I’ve heard DAC differences on the same 2-channel setup before in iFi reviews (see iDAC 2 review).

I tried out uber sensitive IEMs like the Campfire Audio Solaris SE and Campfire Audio Ara. I also tried out the power-hungry but not power needy AME Custom Radioso.

I’m still working on my thoughts on the Campfire Audio Solaris SE, which will probably cement itself in my top 3 listening devices. With my current top 2: the HiFiMAN Susvara and the AME Custom Radioso, the Signature performs superbly. Both the Susvara and the Radioso love power (Susvara ‘requires’ Turbo and the Radioso wakes up on the iDSD Signature only when you jump to Turbo). The amp throws out lots of current and voltage. Most amps tell you how much current they output, but not how much voltage they throw out. The iFi Micro iDSD Signature (and their new Diablo) both tell how much they output in both counts (see below in Specifications), and it is an excellent amount on both counts.

I also tested with the hiss-inducing Noble Encore. With nothing playing I got a slight hiss in Eco mode with no IEMatch. As soon as the music started this dropped below audibility. Turning on IEMatch resulted in a slight bass boost in the midbass making the sound a touch warmer and the bass a bit less muscular while listening to Alvvays – Dreams Tonite (16/44 FLAC). The combo sounds good with a nice wide soundstage. Not bad at all when being fed by LG G8S and iFi USB OTG (my hard-drive died, thus knocking out my Roon library—always back-up your music, don’t run risky like me). I’ll do the Susvara comparisons with the Cayin N6ii (forget to turn it off, even while not playing music and it doesn’t turn off).

xBass and 3D+

Most of the time I don’t use these, as the sound straight out of the box is so good. The bass boost provides a boost that is mostly in the upper part of sub-bass and the lower part of the midbass. It is out of the zone where you would hear the sound signature turn warmer or less clear. The 3D+ feature brings cymbals and tinkling instruments forward in the soundscape and adds a little bit of stage width. It doesn’t sharpen sounds particularly and I don’t note a particular increase in sibilance. Both boosts are tastefully done and great features to have for enhancing matchability of your headphones to your music. As with any tone control, there is still such a thing as too much of a good thing; your mileage may vary. As these boosts are done using analogue methods, there is no digital loss to deal with and the overall fidelity of the music is preserved.

Susvara comparisons

I tried the iDSD Signature with the Cayin N6ii as a source, and found that I preferred it hooked up to my computer with a generic USB3 cable hooked into the iDSD Signature. Thankfully, I found the hard drive that I was using two years ago and have plugged it into my computer for use with JRiver. I’m still crossing my fingers that a data recovery service will recover my 4TB hard drive of music and video. I put 100s of hours into tagging. Roon 1.8 owns the version of JRiver I have for general music playback, and allows grouping zones, which my ancient JRiver doesn’t. On Roon I would be able to have same point instantaneous switching, which you can debate is the only way to compare, or the worst way to compare—psychoacoustics is a far from perfect science with many badly designed experiments trumpeted as having ‘the answer’ on a wide variety of legitimate scientific questions. For this comparison, I have to start playback for two devices in JRiver and switch between them, so there is a little bit of time lag in the playback of the two (positive/negative, who knows?).

I volume matched the two setups to approximately 70dB using an SPL meter and white noise. The HiFiMAN Susvara was used for all the comparison tracks below. The signal chains share the Micro iUSB3.0 and computer. The CMA600i volume knob is set at 14 (I’ve noted this is a good setting to avoid hiss or other artefacts of double amping). The P1 is fed by Blue Jeans Cable Canare 4S11 starquad balanced XLR interconnects. The iDSD Signature was set at about 12:00 on the volume knob. The volume knobs of the final amplifier, are basically the same.

I use Macy Gray – The Heart (24-192, binaural) to test a number of factors: sultry vocals, instrument placement, and speed of treble resolution because of all that cymbal brushwork and speedy tapping. The recording makes the cymbals sound like rolling or crashing rain. It’s stunning. The Questyle/P1 (reference setup) has wonderful reverb on guitar and big body on the stand-up bass when it comes in. Macy’s vocals have a touch of dryness. Switching over to the iDSD Signature. I can’t tell the difference on first switch. With more switches, either my brain convinces me of differences, or I actually hear something. Unfortunately in this case they are so similar that it is really difficult to tell what is truth and delusion. At around 2:50 there is a moving vocal, both figuratively and literally. Macy is moving her head while singing. This movement is a little more defined on the reference setup than the iDSD Signature. The soundstaging of Macy’s vocal has more 3-dimensionality than on the iDSD Signature, but it is not definitive. The stand-up bass on the reference setup is a bit more fluid and organic; while the iDSD signature is a touch dryer and sounding. The reference setup is a touch richer, but I would not define it as a rich sounding setup; neither would I describe the iDSD Signature as dry. With staging, the centre image has more dynamics on the reference setup, but the iDSD Signature places Macy further in front of the other instruments. We’ll have to watch the other tracks to figure out if the mids are more forward, or if the stage is bigger. Forward mids can create the illusion of the latter. The reference setup sounds like it has less depth in the intro passage, the reverb of the room from Macy’s singing is harder to pickup on the iDSD Signature, as if the distance is different. However, the reference setup has more precise sounding cymbal work. It’s faster, while the iDSD Signature sounds smoothed, in comparison. All in all, the presentations are more similar than different, with technical leadership hard to award to either. To my ear, the reference setup is the better sounding on this track, but it isn’t more than triple the price better sounding.

Both the reference setup and the iDSD Signature picks up some mids noise on Leonard Cohen – Leaving The Table (24-44) in the intro. The reference setup has more expressive vocals with more resolution. The same dryness is found here as on Macy Gray’s vocals. The reference setup has more defined note edges, but never sounds etched. On the iDSD Signature there is some smoothing of detail, especially in the treble. Both setups pick up the movement of clothes on Leonard as he sings into the microphone. I wonder how these will do with a really bad recording.

“You called for a really bad recording? Gotcha covered!” says Green Day – Walking Contradiction (16-44). This track has absolutely dreadful mastering. It’s a clear signal that crest factor (see The Loudness War Dynamic Range Database), doesn’t tell you everything there is to know about sound quality. This track is 8DR (dynamic range, difference between loudest and quietest sounds) on crest factor, but is 1.5 loudness units on R128 DR. A crest factor DR of 8 is pretty good for pop-punk. In this case, R128 tells you way more about the sound quality. The cymbals are all sharp short and gratingly metallic. There is next to no sound stage depth or width. It’s a wall of sound, intentionally. The reference setup is honest to this presentation, but manages to still sound okay for a bad recording. Strangely, the more defined presentation of the reference setup makes the cymbals less grating. With the sharpness of the cymbal mastering, having a little break between the strikes is a welcome respite. The iDSD signature blends the sharpness together but doesn’t remove the edge, so it’s like nails on a chalkboard level annoying. Turning on 3D+ doesn’t up the detail, it just makes those nasty cymbals louder, so don’t do it with tracks that have atrocious cymbals (this is true for much of modern metal, you’re welcome, metalheads). This Green Day song doesn’t have any stage depth or width really, but Billie Joe Armstrong is still more out in front of the rest of the band, so the observations on other songs are reinforced here. The iDSD Signature has a slightly forward, but slightly thin vocal presentation.

Schizoid Lloyd – Suicide Penguin (16-44) tests amplitude, aggression and delicacy. The big swells of guitars in the intro punch well on the iDSD Signature. The reference setup is more delicate in the background details with more detailed texture on the guitars. Guitars are a little more forward on the iDSD Signature, which gives the sound a bit more aggression. The iDSD Signature does a good job not smudging together the complex melee of instruments. It does well here, but the reference setup has more full notes and better spacing around instruments. On the reference setup individual vocalists stand out far better. The iDSD Signature is great for it’s price, but the reference setup tops it fairly easy.

The reference setup places Michael’s vocal perfectly on Billy Jean (24-96, vinyl rip), in the middle of the stage with instruments and effects spread around him. Interestingly, Michael’s vocal is a touch further back on the iDSD Signature, very slight. The reference setup does have more expressive vocals while also having more fluid spacial elements. The overall sound is more impactful and better delineated on the reference setup.

The big synth bass in Yosi Horikawa – Wandering (16-44, binaural) comes through delightfully clear and textured on the reference setup with no degree of added warmth or extra sub-bass push on the Susvara. The nature sounds are wonderfully spread around the stage. Comparatively, the iDSD Signature doesn’t reach as deep or with as much body in the big synth bass and the overall stage is further back from the listener. The iDSD Signature is like being in the 6th row, while the reference setup is like a front row seat with synths dripping over you like sweat from a stage musician. I measured both headphones in the same manner, but the manner is imprecise, so on this and the last track, I tried turning the iDSD Signature up to see if it changed the staging or bass impact. It did not, it only changed the volume, the presentation was the same. The bass note and drums in particular have more hollow, boxy presentations, which actually get less refined when I increase the volume of the iDSD. Pushing the Soundaware P1 harder did not change the presentation. Bass was round and full with loads of texture. The iDSD is missing some of the sonic character of the bass. The percussion which sounded a touch boxy on the iDSD sounds more snappy on the reference setup.

Burr Brown Loving?

The Cayin N6ii T01 audio motherboard likely has the same Burr Brown chip in it as the iFi iDSD Signature, but iFi has a ton more experience implementing Burr Brown chips, given that they use them in basically their whole line-up. I mean, iFi is basically single-handedly keeping these chips in production. I’m not complaining. I like the T01 and the iDSD Signature a lot. In order to test out the differences in implementation using a something on the polar opposite end of the spectrum from the Susvara, I plugged in the Campfire Audio Solaris Special Edition (Flower) and volume matched with some good ol’ white noise at 78ish dB.

It takes some work to get the volume down low enough on the iDSD Signature. When queing up Yosi Horikawa – Wandering (16-44, binaural), I actually had to put it in Eco with iEMatch set to High sensitivity. I even considered Ultra sensitivity. With iEMatch not engaged, the volume has to go down into the bottom quarter of the knob, which is where I noted channel imbalance. The Cayin N6ii had similar struggles getting down to low volume. It required Low gain and only went up to 37 out of 100 volume steps. Soundwise, I struggle to tell the amplifiers apart. Any differences I’m hearing are likely to be volume driven, or related to the fact that I’m using iEMatch on one, and not the other. I’ve observed iEMatch to change the sound on some IEMs (not noticeably all). I do note that the synth bass is further back on the iFi, which is consistent with observations vs. the reference setup. Maybe expectation bias, maybe actually a difference in tuning. I will say that I dig the XBass on this track with the Solaris SE. That’s some tasty bass. Turning on 3D+ gets immediately fatiguing, though.

Rebecca Pidgeon – Spanish Harlem (24-96, binaural) is an imperfect, but lovely sounding recording. It’s a real live space with real live people moving and reverb dripping off the walls. The iDSD Signature in concert with the Solaris SE does a wonderful job picking up the charming imperfections of this track. The Solaris SE has a massive soundstage, and the iDSD doesn’t restrict this. In comparison, the bass is more forward on the Cayin N6ii, otherwise, presentation feels pretty similar. Both have black backgrounds and a great feeling of space around instruments. The slightly forward mids of the iDSD Signature make foot steps of musicians moving into place a little more clear, but the tonal character is the same.

Overall, I don’t have a preference between the two Burr Brown setups. The Cayin N6ii is probably a better match for sensitive IEMs, but it is not much difference in chunk-factor compared to the iDSD, but is a fully featured DAP. The soundstage presentation is a matter of taste between the two. If you like slightly accentuated mids the iDSD Signature will match with that preference while the N6ii is a touch more vanilla. I don’t always want vanilla sound, it varies by track and genre.

Specifications

Specifications
Price	$699 (£699)
DAC	Dual Burr Brown Multi-bit
Formats Supported	DSD64-DSD512, DXD384/352.8kHz, PCM 44.1-384, MQA 88.2/96/176.4/192kHz   OR   DSD64-DSD256, DXD768/705.6kHz, PCM 44.1-768kHz. No MQA.
Filters	DSD:      Extreme/Extended/Standard Bandwidth PCM:     Bit-Perfect/Minimum-Phase/Standard DXD:      Bit-Perfect Processing
Digital Inputs	USB 3.0 Type A “OTG” socket with built in iPurifier® technology (USB 2.0 compatible), 3.5mm SPDIF coaxial/optical (optical adapter included)
Battery	4800mAh lithium-polymer, charging via USB-C
Dimensions	172 x 67 x 27 mm (6.8″ x 2.6″ x 1.1″)
Weight	295 g (0.65 Ibs)
Warranty	12 months
Headphone out
Turbo Mode	Power (max)                      10.0V/4,100 mW Power (continuous)         >1,560 mW @ 64Ω; >166 mW @ 600Ω
Normal Mode	Power (max)                      5.5V/1,900 mW Power (continuous)         >100 mW @ 300Ω; >950 mW @ 32Ω
Eco Mode	Power (max)                      2.0V/500 mW @ 8Ω Power (continuous)         >250 mW @ 16Ω
Dynamic Range (HP)	>115dB(A) (Eco Mode, 2V Out)
THD &N (HP 500mW/16R)	< 0.008%
Output Voltage (HP)	>10V (Turbo Mode)
Output Impedance	<1Ω (iEMatch not engaged)
Maximum Output Power	4,100 mW @ 16 Ohm Load
Continuous Output Power	1,000 mW @ 64 Ohm Load
Line Output
Dynamic Range (Line)	>117db(A)
THD & N (0dBFS Line)	<0.003%
Output Voltage (Line)	>2V
Output Impedance	<240Ω
Jitter (correlated)	Below AP2 test set limit

Conclusions

Up to now, the most ‘WOW!’ product I’ve heard from from iFi is the iDSD Micro BL. It was also the classiest and most decked out offering. It’s a desktop dynamo with a Swiss Army knife selection of audio features. I can’t say if this is better, but it is a worthy successor. It is similarly loaded with features to the iDSD Micro BL, adds s-Balanced 4.4mm headphone out, while losing the ability to be a standalone amplifier.

The ability to flip a switch and get more bass or treble presence and the built in iEMatch and boss amp on the iDSD Signature are traits not matched by most DAPs or DAC/Amps in any price bracket. The iDSD is easy to embrace for just about any use-case outside of strapping to your arm in a gym.

I’ve reviewed a couple powerful iFi transportables. I found that the iCAN SE didn’t really do the very best headphones justice. It’s 4W into 16Ω power didn’t sound as fully developed as other similarly powered amps I have heard or have on hand with headphones like the HiFiMAN HE-6 or the Susvara. At the time of that review I didn’t have any demanding in ears in house, now I have some electrostatic hybrids that just love power. This is what I said about the iCAN SE:

“Yes, you can drive an HE6 or a K1000 with this (and probably the Abyss and LCD4), but if you are printing money to buy those headphones, you probably want to hear them at their best and probably have heard them at or near their best. I can’t imagine using my top-tier power hungry full-size cans while traveling, unless I had an amp that made them sing enough to make me feel like I couldn’t part with them. The iCAN SE is not that amp for me. It is an excellent amp for $299, but it is probably unreasonable to expect it to make the rare beasts above sound their best.”

I can’t say that about the Micro iDSD Signature. I did my primary comparison against my current favourite signal chain for the Susvara and it didn’t beat it, but it did well enough that I would be happy to take my best demanding cans and hook them into the iDSD Signature if I was headed away from home for a while. The sound is refined with a little bit of mids accentuation that makes bass sound slightly more distant and gives the impression of a deeper stage. This iFi iDSD Signature is dynamite in a teeny tiny package.