Digital-to-analog converter / headphone amplifier
he iFi products iFi have earned their own nickname: "the Swiss Army Knife". And rightfully so - when we take a look at the latest version of the flagship product of iFi Micro series, Micro iDSD BL (Black Label), it will be difficult to argue. This compact device is a DAC, headphone amplifier and preamplifier. The DAC section accepts via the USB input all currently used digital signals, both DSD and PCM:
It also accepts, via the „combo” RCA/optical input PCM signal up to 24 bits and 192 kHz. As far as I know it is one of very few converters that can works with native signals up to DSD512 and PCM 768 kHz, meaning with any downsampling (True Native). It can do it utilizing Burr-Brown DAC chip. A multi-color LED informs user what kind of signal DAC receives in any particular moment. It's a similar, although a bit more elaborate solution is used by Chord and one can get used to this kind of communication.
The device is equipped with variable digital and analog filters, interchangeable output voltage for headphone output allowing user to adjust the signal level to their effectiveness, the processor named 3D+ Holographic Sound System that enhances spacial aspect of the presentation, processor energizing bass (XBASS +) and other features. If this product was made by some other brands we would see dozens of logos, names, technical details. The iFi guys, however, have a special gift of giving proper names and organizing information in an orderly way. Reading the descriptions on their website is so pleasant adventure.
MICRO iDSD BLACK LABEL
The black "label" version (associations with Jack Daniels seem fair) has been carefully tweaked by iFi's designer, Mr. Thorsten Loesch, who says about his new piece of work: "it's been tuned up through the roof" and "sound even better than it looks." It's heart are two, one per channel, latest D/A converters from Burr-Brown, used in this device and in flagship Pro model. They are now clocked with an extremely precise "femto" clock, which was originally developed for high-end AMR CD players and is called the AMR named Global Master Timing. It allowed designers to further minimize jitter.
The analog section instead of the classic integrated circuits features exceptionally rarely used, custom-made OV2627 and used to stabilize the voltage sensor, OV2028. Made by one of the German companies (hence the name OV = Operationsverstärker), they use HCOFC copper lead-frames and 4N Gold bond-wire instead of commonly used aluminum.
The power supply has also been improved by using highly prized electrolytic Sanyo Os-Con capacitors, now manufactured by Panasonic. Originally they were used for the top AMR CD Player, CD-77, because they cost 10 times more than conventional capacitors. iDSD features as much as 12 of them. A new feature are also tantalum capacitors from Kemet and high quality resistors for SMT. The Xbass technology has been redesigned as well as the 3D one, now with a "plus" in the logo. Also headphone output stabilization network offers now less distortion. The latter is able to drive even the most difficult headphones.
The device features an USB input for a computer, a second USB through which one can charge Apple devices, as well as digital RCA and TOSLink (S/PDIF) inputs in one "combo-type" socket. So we can use either RCA or the TOSLink. To use a classic optical cable we need to use an appropriate adapter that is delivered together with the device. It's worth noticing that one gets a lot of accessories with the iDSD - different types of adapters, non-slip mat, small rubber feet that one can stick to the bottom of the device, analog interconnect, short mini-jack / mini-jack cable and two rubber bands one can use to hold the device and a smartphone together.
I left out one of the most important information until now - the iDSD BL is powered by a lithium-polymer battery. That means it can be used as a portable device. In the box one won't a charger, only a USB cable to be used with a smartphone charger. How long the iDSD BL will work on one charge will depend on the volume output and efficiency of the connected headphones. With the most demanding loads, ie. HE-6 HiFiMAN one should be able to listen to music for 6 hours, and with some easier to drive, such as high-efficiency Sennheiser IE-800 even up to 12 hours. Note that if you do not use the converter the device can serve as the Power Bank and should be able to charge an iPhone twice.
Recordings used for the test (a selection)
Japanese issues available at
The "Black" iDSD has been tuned in two ways, by replacing key components for higher quality ones, and by using multiple careful listening sessions to introduce such changes in the circuit that would allow to better utilize the potential of this device. Which is pretty clear. I used this converter in a system where each element, even anti-vibration feet, is more expensive that the reviewed item, and yet I did not feel any discomfort. For a few days, before I proceeded to the formal assessment, I used only the iDSD BL in my listening sessions using both, headphones and loudspeakers.
The sound of the BL DAC was voiced in such a way that it reminded me of a turntable performance. That's my impression, at least. Maybe the components they used as replacement pushed the performance in this direction, and iFi engineers made the best of it. There is also another possibility – maybe the idea was to make the digital files in any format and resolution to sound in a way that we expect from the hi-res files, ie. in a rich, dense way. Regardless of the intention, it worked really well - the sound this device delivers meets all of these assumptions.
iDSD BL replacing in the system some expensive digital and analogue sources fits into this type of presentation perfectly. It delivers dense, big-scale, avid sound that allows for a differentiation of small changes of tone, dynamics and detail. The treble sounded fantastic, as it was resolving, selective and resonant. Since the sound as a whole is bit darker than, for example, my reference Player, one might say that it sounds warmer. But the sound is not rounded. I found it surprising, but the much more expensive Exogal Comet Plus DAC compared to iFi sounded as if it had a rounded attack and warmer sound, despite the fact that the tonal balance with the American converter was set higher.
iFi delivers the density and purity without making the sound brighter. The lower midrange and upper bass are powerful, so the sound doesn't seem lean. Yes, obviously the more expensive devices generate bigger volume of the sound, everything is bigger and more substantial. Even if I'm talking about a CD player compared with iFi playing DSD128 files. It's one of the features of high-end products - the better one, the sound sources, such as vocals and instruments are larger, more three-dimensional, have better defined shape. But even placed in such a difficult situation the iDSD BL did very well, playing music with proper momentum and power.
This powerful bass surely helps. It is not particularly well extended, doesn't go very low, but one can realize that only if (a) compares it with a much more expensive device, and (b) has loudspeakers capable of conveying lowest notes. Under normal conditions, ie. in systems in which iFi will likely be employed, users will not even know about it. Although I wouldn't recommend limiting usage of this device only to entry level systems. We would lose a chance to save a large amount of money - if we accept the limitations I mentioned, the converter is able to play in much more expensive systems, and nobody will realize that our DAC is two or three times cheaper than the amplifier or loudspeakers. It does offer a balanced and refined enough performance to achieve that. But one might use it also with headphones ...
First I listened to iFi as a DAC, then as DAC and headphone amplifier using a digital input. Its performance in a system with loudspeakers was very good, and it left a favorable impression. Nevertheless, as a headphone system it proved it could do even more.
First of all, the manufacturer's claim that iDSD BL is able to drive any headphones is true. I tried it with the HiFiMAN HE-6 and it turned out to be one of few cases when I didn't feel as if these cans were not properly driven. Usually I achieve this with large, powerful amplifiers, and here this little box did the same. With current less demanding and better sounding models of this manufacturer, such as HE-1000 v2 and Edition X v2 iFi delivered an extremely clean and dense sound.
XBass+ | 3D+Every time I used the XBass + system and I'm not ashamed of it. Change in the tone was clear, but at the same time so subtle that it did not change the tone of the midrange. To check that I listened to recordings of vocal Renaissance music, including The Hilliard Ensemble and Alamir. The vocals in these releases are placed quite high, so the XBass + does not influence them directly, at most, increasing the acoustic environment (volume). This system did not affect voice in any negative way, which proved its good implementation. On the other hand, whenever I wanted a punchy, powerful bass, it worked very well not overloading the presentation but rather completing it.
After my initial attempts to behave like a true purist I finally gave up and left the 3D + system also on all the time, just because in this case it clicked perfectly with the nature of the amplifier and the requirements of my headphones. The sound with it on is genuinely more spacious, it comes out from the "head" and remains at the same time tight and focused, which other “space enhancing” systems can't do.
The sound of such a system is excellent because it is well-defined and saturated, refined. It performed really well with both, recording of Röyksopp doe, so the electronic music, as well as with the Master CD with Polish Jazz. Each of them presented its own “face” though. But every time I could hear a great treble and a nice midrange – which is what I described in the section about loudspeaker listening. The scale of the sound is smaller than with the reference vacuum tube amplifier, Ayon Audio HA-3, but that's what I expected, each technical solution has its limitations. Quickly, however, I adopted to this change and after a short time I did not pay attention to this difference anymore.
iDSD BL will be a good match for both, entry-level and much more expensive systems. It sounds a little warm, with an emphasis in lower midrange. Its macro-dynamics is slightly eased, and the bass doesn't go as deep as with more expensive sources. So what? - it still sounds very accurate, tight, focused, rich and resolving. On top of that comes this very musical and highly current efficient headphone amplifier, which can be used with both, inexpensive headphones like AKG Y50 (Polish), in-ear Focal Spear and AKG K3003 (Polish) as well as with the most expensive planar-magnetic cans. Every time iFi will present headphone's own sonic character, never obscuring it with its own problems.
iDSD Black Label is a tiny device featuring an aluminum housing painted black. All the writings were made using an orange lacquer and I have to admit that this combination looks really good. Same combination was previously used by Bakoon, Vovox and Chord and it always worked perfectly for their products.
The Sockets and manipulators are positioned at the front, rear, on the side, and even underneath, which clearly reflects the complex nature of this device. On the front there is a volume control knob, coupled with the on/off switch, “large jack” 6,3mm headphone socket, line 3,75mm "mini-jack" input, as well as two flip switches for XBass + and 3D + systems; Both work only with headphone output.
On the rear panel one finds: analog RCA line outputs and three digital sockets, ie. USB serving as input and charging socket plus a "combo" RCA/TOSLink jack. The latter may serve as either a digital input or as an output. On the side there is another USB input, which can be used to charge an Apple device. On the other side there are three softly but surely working buttons:
- One is used to set a maximum current for the headphone output in three steps depending on cans' efficiency. Time the device will work on one charge will depend also on the chosen setting; Turbo = 6 hours, Normal = 9 hours, Eco = 12 hours.
Underneath there are two more switches:
The electrical circuit sits on a single PCB. The USB input features XMOS chip, and the S/PDIF digital receiver comes from Wolfson Microelectronics. D/A Conversion is handled by two Burr-Brown DSD1793 dual-core chips, one per channel. These latest chips accept DSD and PCM signal in native form, without conversion. The I/U conversion and signal amplification is performed by custom-made OV2627 op-amp with FET input. The OV2028 is used as voltage regulator. The power supply features great Os-Com capacitors. Headphone amplifier features no coupling capacitors, and this solution is called DirectDrive.
Specifications (according to manufacturer)
- Turntable: AVID HIFI Acutus SP [Custom Version]
- Cartridges: Miyajima Laboratory KANSUI, review HERE | Miyajima Laboratory SHILABE, review HERE | Miyajima Laboratory ZERO (mono) | Denon DL-103SA, review HERE
- Phono stage: RCM Audio Sensor Prelude IC, review HERE
- Compact Disc Player: Ancient Audio AIR V-edition, review HERE
- Line Preamplifier: Polaris III [Custom Version] + AC Regenerator, regular version review (in Polish) HERE
- Power amplifier: Soulution 710
- Integrated Amplifier: Leben CS300XS Custom Version, review HERE
- Stand mount Loudspeakers: Harbeth M40.1 Domestic, review HERE
- Stands for Harbeths: Acoustic Revive Custom Series Loudspeaker Stands
- Real-Sound Processor: SPEC RSP-101/GL
- Integrated Amplifier/Headphone amplifier: Leben CS300XS Custom Version, review HERE
- Headphones: HIFIMAN HE-6, review HERE | HIFIMAN HE-500, review HERE | HIFIMAN HE-300, review HERE | Sennheiser HD800 | AKG K701, review (in Polish) HERE | Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, version 600 - reviews (in Polish): HERE, HERE, HERE
- Headphone Stands: Klutz Design CanCans (x 3), review (in Polish) HERE
- Headphone Cables: Entreq Konstantin 2010/Sennheiser HD800/HIFIMAN HE-500, review HERE
- Portable Player: HIFIMAN HM-801
- USB Cables: Acoustic Revive USB-1.0SP (1 m) | Acoustic Revive USB-5.0PL (5 m), review HERE
- LAN Cables: Acoustic Revive LAN-1.0 PA (kable ) | RLI-1 (filtry), review HERE
- Router: Liksys WAG320N
- NAS: Synology DS410j/8 TB
- Interconnects: Acrolink Mexcel 7N-DA6300, review HERE | preamplifier-power amplifier: Acrolink 8N-A2080III Evo, review HERE
- Loudspeaker Cables: Tara Labs Omega Onyx, review (in Polish) HERE
- Interconnects: Acoustic Revive RCA-1.0PA | XLR-1.0PA II
- Loudspeaker Cables: Acoustic Revive SPC-PA
- Power Cables: Acrolink Mexcel 7N-PC9300, all system, review HERE
- Power Distributor: Acoustic Revive RTP-4eu Ultimate, review HERE
- Power Line: power cable Oyaide Tunami Nigo (6m); wall sockets 3 x Furutech FT-SWS (R)
- Power Cables: Harmonix X-DC350M2R Improved-Version, review (in Polish) HERE | Oyaide GPX-R (x 4 ), review HERE
- Power Distributor: Oyaide MTS-4e, review HERE
- Stolik: SolidBase IV Custom, read HERE/all system
- Anti-vibration Platforms: Acoustic Revive RAF-48H, review HERE/digital sources | Pro Audio Bono [Custom Version]/headphone amplifier/integrated amplifier, review HERE | Acoustic Revive RST-38H/loudspeakers under review/stands for loudspeakers under review
- Anti-vibration Feets: Franc Audio Accessories Ceramic Disc/ CD Player/Ayon Polaris II Power Supply /products under review, review HERE | Finite Elemente CeraPuc/ products under review, review HERE | Audio Replas OPT-30HG-SC/PL HR Quartz, review HERE
- Anti-vibration accsories: Audio Replas CNS-7000SZ/power cable, review HERE
- Quartz Isolators: Acoustic Revive RIQ-5010/CP-4
- FM Radio: Tivoli Audio Model One