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A Review On: iFi Audio micro iDSD

iFi Audio micro iDSD

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Pros: Octa-speed DSD, femto clocks, overall sound quality, gain options, digital filter options, discrete XBass+ and 3D+ sections, battery powered

Cons: Flimsy-feeling plastic switches, male USB A USB input, bulky size for true portable use

This is a review for the micro iDSD Black Label edition, not the original micro iDSD

I firstly want to thank Lawrance at iFi for letting me use the micro iDSD Black Label for a few months. I had originally requested the micro iDSD, but the timing of the request was right in line with the launch of the Black Label edition.

This was a brand new unit, so I let it burn in for quite some time in case I receive any scrutiny about that. : p

Product Score Summary:
Value: 5/5
Audio Quality: 4.5/5
Quality: 4/5
Design: 4/5
Overall: 4.375/5

Video Time Markers (Click to show)
Video Time Markers:
0:11 - Thank you to iFi
1:02 - micro iDSD vs micro iDSD Black Label differences
2:01 - Usage of the micro iDSD BL
2:23 - IEMatch
4:23 - Polarity switch
4:41 - Digital filters
5:24 - DAC architecture
6:04 - DAC sound quality
7:47 - Imaging and femto clocks
8:55 - Soundstage
9:10 - Price and affordability
9:17 - Amplifier power output and sound quality
10:41 - Ocata-Speed DSD
11:41 - Upsampling to DSD256
13:48 - micro iDSD vs Black Label appearance
14:27 - XBass+ and 3D+ switches
16:36 - Digital filters
18:07 - Price/performance evaluation
18:58 - Male USB-A connector
20:06 - [Problem fixed from firmware upgrade]

Most people don't know this, but the orange paint on the micro iDSD Black Label fluoresces under UV light. It makes for a cool photography subject, hahaha.

Box Contents (Click to show)

I made an unboxing video to explain what goodies are included with the iDSD BL box, as well as a basic overview of the unit. Like most, if not all, iFi products, you will be equipped with all of the items you would ever need for the product inside of the box.
Video Time Markers (Click to show)
Video Table of Contents:
2:12 - iFi disclaimer
2:44 - Box sleeve overview
3:15 - micro iDSD Black Label overview
4:24 - Back panel input/outputs
5:07 - Bottom labels and switches
6:33 - Warranty card and user manual
7:11 - Accessory box 1 contents
7:35 - Female USB-A to female USB-B adaptor and explanation
9:02 - Accessory box 2 contents

Or for a too long; didn't watch overview:
  • RCA - RCA cable
  • 3.5 mm - 3.5 mm right-angle stereo cable
  • mini-TOSLINK adaptor
  • Female USB A - male USB A cable
  • Female USB A - female USB B cable adaptor
  • Female USB A - female USB B adaptor
  • Silicone mat
  • iFi-branded silicone feet
  • Velour carrying pouch
  • Silicone caps for the RCA and S/PDIF jacks
  • 3.5 mm - 6.3 mm adaptor
  • 2x silicone bands

Design (Click to show)
Design: 4/5
One of the things that sets the micro iDSD Black Label apart from other DAC/amps is its design. Using the same chassis as the other micro line of products, the iDSD BL carries its unique shape and form factor. This is, however, why I docked a point from the Design score. Although the iDSD BL is portable, there is no way it would fit comfortably in a pocket. This is more of a transportable DAC/amp than a portable one, and that limits its functionality. On the other hand, since transportable DAC/amps are smaller than desktop-sized ones, it does have the benefit of being able to fit on a cramped desk more easily.

If you want to use the micro iDSD BL as a truly portable DAC/amp, there is a battery inside of it that lasts 6-12 hours depending on usage. I almost exclusively used it as a USB-powered DAC/amp with my laptop though since that's how I would use it.

With the idea of portability in mind, the use of a male USB A connector makes sense since you can just use a Lightning - female USB A adaptor, or an OTG cable for Android-based devices. However, since I consider this more of a transportable unit than a portable one, having the use of a male connector is an inconvenience if you want to use your own USB cables, or audiophile ones at that. iFi's own Mercury nor Gemini cables are compatible with the micro iDSD BL without the use of an adaptor.

Outside of these issues, I think the design of the micro iDSD BL is pretty solid. From the outside, the whole chassis is utilized in terms of inputs/outputs/switches. The Black Label edition goes for a stealthy black-orange appearance and I like that very much. On the bottom of the unit, there is some print in a glossy black paint such that it's very discrete, yet available if you need to refer to it. One small complaint I have is the lack of a clear indicator of where the volume knob is at: there's only a very small, uncolored, dimple near the edge of the front part of the knob.

The whole concept of the micro iDSD BL being the "Swiss Army knife of audio" is really exciting to see. It has so many inputs and outputs, gain and power output settings, and audio tweaks in general that it should satisfy anyone who likes to modify their systems' sound. The only set of options you won't see in this device are balanced inputs/outputs, but given the size of the chassis and the sheer amount of stuff crammed into the device, it is quite understandable. The combo S/PDIF/coaxial input/output port should be quite useful to many.

Moving to the inside, the Black Label edition adds some improvements to the circuit that should be appreciated. Having femto-second global master timing clocks is not a trivial thing to be added in a sub-$1000 device, let alone sub $600. That to me is just mind-blowing. Upgraded components both in the digital and analog sections of the device are also welcome, in addition to the XBass+ and 3D+ additions, which I think are well-done. The XBass+ and 3D+ features are separate analog effects done on the headphone output, so it's not just a DSP effect.

The design choice to use a hybrid R-2R/ΔΣ Burr Brown DAC chip is fascinating! Basically this DAC chip takes the 6 most significant bits of your PCM source file and does a digital-to-analog conversion process through a R-2R resistor ladder, true multi-bit, process. The remaining bits go through a typical Delta Sigma modulated pathway.

The DAC chip also decodes DSD natively in a true 1-bit fashion that only involves a single low-pass filter.

On top of all of this, the DAC is capable of playing back DSD512 (Octa-speed DSD) and 24/768 PCM. Not that there's any music in this format, but a 24/768-capable DAC is able to transfer DSD256 via the DSD over PCM protocol without any problems for Mac OS users.

The use of 3 different filters for your music also allows the user to tune the device to their own liking and to experiment with the concept of filters. In my review video, I had mentioned that the filters seemed to be more like digital filters. This is only half-right. The filter switch acts as a digital filter selection during PCM playback. For DXD playback (which is actually still PCM), a fixed analog filter is used. Likewise for DSD playback, a selectable analog filter is used. This is a very unique set of features for filters that I have not seen in any other device in any other price range. Kudos to iFi for including this as a design feature!

Furthermore, the inclusion of not one, but two gain systems allows the micro iDSD BL to have an incredible amount of versatility for use with headphones. Eco, Normal, and Turbo gain modes are kind of your standard low/medium/high gains respectively. However, the micro iDSD BL has an additional 2-stage gain stage meant to be used for sensitive headphones and in-ear monitors specifically: IEMatch. I think this design is simply brilliant, and more devices should have something like this, seriously.

Quality (Click to show)
Quality: 4/5

Since this category is really arbitrary, I will use this section to rate the micro iDSD's overall build quality and feel.

The only reason why I docked a point from this category is that the switches don't feel very robust minus the metal flip switches for the XBass+ and 3D+ settings. The rest of the switches are rather cheap-feeling since they're just plastic and they don't have a lot of resistance. I didn't add the silicone feet to this unit since I am not the owner of it, so I mostly just placed the micro iDSD BL on the silicone mat instead.

I don't mind having buttons or switches on the bottom of a unit as long as they don't accidentally get activated. Unfortunately most of the switches on the micro iDSD BL tend to get moved easily, and this adds to the problem of having this unit in a pocket for portable use.

For everything else around the device, things seem to be of top-notch quality. The chassis feels diamond-solid [better than rock-solid] and super robust, the paint seems to be of high quality and I don't see it chipping off in the long-run, the inputs/outputs feel solid and not flimsy or loose, and the volume knob is silky smooth to use (actually it's pretty addicting to turn since it feels smooth but it has a very, very, very nice sense of resistance; seriously, try it out!).

Audio Quality (Click to show)
Audio Quality: 4.5/5

I'll start by mentioning the amplifier section. I am personally not a huge advocate for amp matching with headphones. If it gets loud enough, that's usually good enough for me since I listen to music at fairly low volume levels.

With this in mind, I think the amplifier section of the micro iDSD BL is great. It can drive my Etymotic ER4SR and OPPO PM-3 with ease, specifically in Eco/Ultra-Sensitivity settings. Again, if it gets loud enough, it's good enough for me; there is absolutely no reason for me to use higher gain settings for these headphones. The background is dead silent without any traces of hiss at all. Only when I turn off the IEMatch and turn the volume all the way up on Normal gain do I start to hear background hiss. However, at this point, you wouldn't be using such sensitive headphones from the get-go.

I did get the chance to hear the micro iDSD BL with a Sennheiser HD800. I just used Normal gain mode and it drove them just fine like a typical solid state amplifier without any issues. I'm still not a huge fan of the HD800 myself, but at least the micro iDSD BL can do a comprable job at driving it.

I have no idea when anyone would ever use the Turbo gain mode on the micro iDSD BL. Perhaps to be able to drive the infamous HiFiMAN HE-6, or maybe even the AKG K1000? I didn't get the chance to use the micro iDSD BL with such insensitive headphones unfortunately. Those headphones aren't easy to come by in the first place, but it's, again, good to know that the micro iDSD BL has a gain mode for them: 4 watts of power into a 16-ohm load is not a trivial thing to do in a battery-powered audiophile-targeted device.

XBass+ and 3D+
Briefly mentioning the XBass+ and 3D+ switches, I actually really liked them. Unlike some devices, the micro iDSD BL uses discrete circuit pathways for these two settings, which are also all analogue and not digital (AKA not DSP).

The XBass+ might not be for everyone since it's a pretty substantial boost, but I liked it because it was in the lower-/mid-bass area and it didn't affect the upper-bass/lower-midrange a whole lot. This is my preferred way to do a bass boost since it stays more true to being a bass boost.

The 3D+ switch is essentially a crossfeed effect, but again, it is all analog. I typically don't like using crossfeed since it sounds weird to me, but the micro iDSD BL seems to do it more justice than not. I should give a warning that it does seem to make recordings brighter-sounding, so if you have a bright music, it might be too much. That being said, enabling the 3D+ switch sounds like it angles the music 30˚ inward from the horizontal, kind of like speakers pointed at your head. Neato!

Now on to the DAC portion of the micro iDSD BL. I think this is where the sound aspect gets interesting. I spent most of my time listening to the micro iDSD BL as a DAC with the STAX SRS-2170 system.

I firstly want to make it clear that most of my listening sessions were done with the Standard digital filter. These filters could arguably affect how people perceive the sound. Between the three digital filters, the Standard one sounded the best to me. Here's a summary of how I felt between the filters, although I must stress that the differences are pretty subtle and not everyone may hear them:
  • Standard: The least harsh-sounding filter to my ears, with a larger sense of space, but at the cost of a limited ability to image
  • Minimum-Phase: Harsher-sounding to me compared to the Standard filter, and has a reduced soundstage, but better imaging (having more space between instruments)
  • Bit-Perfect: I really couldn't hear a difference between this filter and the other ones

Playing PCM files in this manner, I noticed that the micro iDSD BL kind of has a "Goldilocks" sound compared to other DACs I'm used to hearing. The ESS-based DACS typically have a bright and more detailed sound ("SABRE SOUNDTM"). On the other end, AKM-based DACs tend to sound really warm. Perhaps it's due to iFi's use of the hybrid Burr Brown chip, but I find the micro iDSD BL to sound a bit warm as a whole while having a somewhat detailed sound: it's a blend of both the AKM and ESS DAC chips' sound.

Perhaps it's due to the Global Master Timing of the micro iDSD BL's femto clocks, as I've found to be the case for other femto clock-carrying DACs, but I really marveled how well the micro iDSD BL can image. It didn't have the largest-sounding soundstage that I've heard in a DAC, but being able to determine where an instrument is within the soundstage and how clear that instrument is from another is more important for how I listen to music.

Playing DSD, I really like how the micro iDSD BL sounds. Smooth is the best way to describe it. Again, the Burr Brown chip that the micro iDSD BL uses has a true DSD playback loop in that a 1-bit digital-to-analog conversion is done with a single low-pass filter. The filter switch in the case of DSD only changed the volume to my ears, so there's not really much to say about those.

I liked the sound of the micro iDSD BL's DSD playback so much that I used software to upsample my music to DSD256 throughout most of my listening tests. One of the original reasons why I wanted to hear the micro iDSD in the first place was because I was interested in iFi's "Octa Speed" capability. In OS X, you can only play DSD music through the DSD over PCM (DoP) protocol in which the DSD source is disguised as a PCM file so the computer can transfer it to the DAC to be decoded as DSD (note that this is NOT a conversion process). Therefore, playing back DSD256 music... Math (Click to show)
DSD256 data rate = 2 channels * 1 bit * 44.1 kHz * 256 = 22.5792 Mbps

Equivalent PCM data rate = 2 channels * 16 bits * 44.1 kHz * 16 = 22.5792 Mbps (AKA 16-bit/705.6 kHz)
requires a DAC capable of reading a 16-bit/705.6 kHz signal. Obviously the micro iDSD BL can accept a 32-bit/768 kHz signal, so this is probably one of the only DACs that can play back DSD256 music on OS X! Unfortunately in Windows 10, I couldn't get the DSD512 stream to work properly as it kept stuttering for me.

Upsampling even CD-quality files seemed to make them sound smoother to my ears. Daft Punk's "Derezzed" song is one of my favorite test tracks to use for bass and brightness. When I talked to the iFi folks at CanJam at RMAF last year, they mentioned that they liked "Derezzed" too, but it can be pretty harsh-sounding at times, in which I agree and that's why I use it as a test track. I asked them about their "Octa-Speed" feature since there's probably like 5 music tracks in the world that are recorded in DSD512 and they mentioned that upsampling "Derezzed" to higher DSD rates actually helped reduce its harsh sound. This is exactly what I heard when upsampling any music track to DSD256: things just become less harsh overall and the sound seems to become smoother and more pleasing to the ears because of this.

One theory I have for this phenomenon is due to the nature of DSD decoding. All of the songs' original frequency content is still retained, but higher rate DSD sampling rates have higher signal to noise ratios. This in combination with the Burr Brown's true DSD pathway might benefit the digital-to-analog conversion process.

Value and Conclusions (Click to show)
Value: 5/5

If you couldn't tell by this review, I really, really, really like the micro iDSD BL, and especially for the price. Considering all of the features this device has, combined with all of the included accessories, and its overall sonic performance, I think this device could be double the price and I would still recommend it. Seriously, this is one beast of a device.

Outside of the largish/portablish design, the kind of annoying male USB A connector, and the somewhat flimsy-feeling plastic switches, I'd whole heartily give the micro iDSD BL two thumbs up. I still can't believe iFi is only setting this at a $549 USD MSRP. That's just mind-boggling.

Thank you for taking the time to read/peruse through this review! : )


Awesome review! I too used to transcode poor recordings to DSD with the original Micro. Found I had to increase latency settings a bit to make DSD512 sound stable.
Thank you for a very detailed review: I can skip reading the manual now :-)
Two quick questions, if I may:
1) How do you suggest to connect the BL to a Mac Mini since the USB 3 cable provided is     male-to-female and the USB ports are female on both sides?
b) How do you upsample to DSD512 (or 256), again on a Mac?
Thanks again
My first question was answered by watching your excellent unboxing video :)) 
Thank you! I tried to change the buffer settings a bit, but I couldn't find one that worked out for my computer.

Thank you for the kind words!
You firstly need the appropriate media player. Audirvana+ or JRiver Media Center support the upsampling feature. In A+, open the preferences, go to the Audio Filters tab, click on the DSD button and set the option to DSD256. In JRMC, go to the options, Audio tab, Settings section, DSP & output format, check the Output Format tab, click on the Output Format tab, and select 4xDSD in DoP format from the drop down menu under Output Encoding.
I tried Audirvana+ for a while, but I was not happy with its library import and management features. I am in fact about to give JRiver a try, so I will definitely follow your advice and see how it pans out.
Thank you!
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