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Positive Feedback ISSUE 69
september/october 2013


iFi Audio (Micro), iUSB POWER, iDAC, and iCAN
by Wojciech Pacuła, translation by Andrzej Dziadowiec


iFi Audio Micro iUSB POWER iDAC and iCAN

USB Power Supply+ USB D/A Converter + Headphone Amplifier

"Small is beautiful" stands in opposition to "Size matters", doesn't it?

Thorsten Loesch (assisted by Pat Wayne as a co-designer), head of Abbingdon Music Research (AMR Audio) and now also of iFi Audio  has ambitions to parallelly explore these two seemingly disparate directions. AMR offers swanky, large, really large audio components—amplifiers, CD players, and DACs, a phono preamplifier and speakers. They are all very traditional in terms of finish style, size and applied design solutions. They are what is routinely associated with audiophilism and high-end. iFi's product lineup, on the other hand, the latest child of Abbingdon Global Group, is focused on tiny micro-components that work with computers and are most at home on a desk of a young but already demanding music lover.

There's plenty of such components on the market. Chinese and Taiwanese manufacturers excel at this type of production, having found a gap in the market. A large initial capital outlay is not required as common circuit designs and small repeatable enclosures can be used. The units are powered by mass produced wall-wart style power supplies. And it works—the products are reasonably priced, look good and bring lots of joy to the user.

iFi Audio Micro iUSB POWER iDAC and iCAN

Thorsten Loesch has years of experience with manufacturers from the Far East and is well versed in their capabilities. He put his knowledge to good use and has iFi products manufactured in China. The circuits are designed in the UK, however, where AMR is headquartered. This way iFi can offer interesting design solutions at very attractive prices. The company current product lineup includes the iDAC USB D/A converter, the iUSB Power USB audio power supply, the iCAN headphone amplifier, the iPhono MM/MC phone preamplifier and the iLink USB to SPDIF converter. The system can be set up by using a dual-headed USB cable with two Type A connectors, called the Gemini ("twins"). At the time of writing this review the manufacturer's website was running the countdown to showcasing the latest and perhaps most ambitious yet-to-be-named component. I was looking at it with a self-content smile as I had already been testing it for a few days. It's the iTube, a tube buffer to correct impedance and improve soundstage reproduction. This is one of the best additions to my reference headphone system! I received for a review the iUSB Power, iCAN, iDAC and iLink. Since the first three form a natural system, I left the iLink for another review.

Testing Methodology

Testing methodology was especially important with this system. The source was my HP Pavilion dv7 laptop running Windows 8 Pro x64, with 8GB RAM, 128GB SSD + 520GB HDD, and JPLAY/foobar2000 software audio players. The iDAC was compared against the Asus Xonar Essence STU and the Jeff Rowland Aeris (see HERE). Having auditioned the DAC on its own I hooked it up to the iUSB Power. To connect the computer I used two USB cables interchangeably: the Acoustic Revive USB-1.0PLS and the Wireworld Silver Starlight. To connect the power supply I used the Acoustic Revive USB-1.0SPS with two Type A connectors. The amplifier was connected via the Wireworld Equinox7 interconnects. They came in handy as the iFi input connectors are very close to each other, which precludes using oversized connectors.

Finally, I connected the iDAC—powered from the outboard power supply—to the iCAN headphone amp. To assess the sound of the headphone amp and of the whole system I used four pairs of headphones: the HiFiMAN HE-6, the HiFiMAN HE-300, the AKG K3003 and the AKG Q460. For a comparison I had the Bakoon HPA-21 amp coupled via the iFi's iTube buffer.

In addition to the reference system I also used another system in which the iFi is more likely to be used—that of my son. Its basic component is the all-in-one Arcam Solo Mini driving the Castle Richmond Anniversary. The source is a classic desktop PC with Windows 7 x64 and foobar2000, connected via USB to the Hegel HD11 DAC and from there to the Arcam.


Albums auditioned during the review

(CD rips)

Assemblage 23, Bruise, Accession Records A 128, Limited Edition, 2 x CD (2012).

Audiofeels, Sounds of Silence, WAV 16/44.1 from Audiofeels, Uncovered, Penguin Records, 5865033,

Bach, Violin Concertos, Yehudi Menuhin, EMI/Hi-Q Records HIQXRCD9, XRCD24, CD (1960/2013).

Black Sabbath, 13, Vertigo/Universal Music LLC (Japan) UICN-1034/5, 2 x SHM-CD (2013).

Clifford Brown, Memorial, Prestige/JVC VICJ-41562, Digital K2, CD (1953/2006).

John Coltrane, A Love Supreme (Deluxe Edition), Impulse!/Verve Music Group 589 945-2, 2 x CD (1965/2002).

Kraftwerk, Minimum-Maximum Kling-Klang Produkt/EMI 3349962, 2 x SACD/CD (2005).

Mills Brothers, Swing Is The Thing, History 20.3039-HI, The Great Vocalists of Jazz & Entertainment, CD.

Patricia Barber, A Distortion of Love, Verve/Mobile Fidelity UDSACD 2100, No. 01083, SACD/CD (1992/2012).

The Mills Brothers, Spectacular, Going for a Song GFS275, CD.

(Hi-res files)

Random Trip, Nowe Nagrania 005, CD + FLAC 24/44,1 (2012); reviewed HERE.

SATRI Reference Recordings Vol. 2, Bakoon Products, FLAC 24/192.

T-TOC Data Collection Vol. 1, T-TOC Records DATA-0001, 24/96+24/192, WAV, ripped from DVD-R.

Al Di Meola, Flesh on Flesh, Telarc, 24/96 FLAC, source: HDTracks (2011).

Charlie Haden & Antonio Forcione, Heartplay, Naim Label, 24/96 FLAC, source: NaimLabel.

Dead Can Dance, Anastasis, [PIAS] Entertainment Group, PIASR311CDX, Special Edition Hardbound Box Set, CD+USB drive 24/44.1 WAV (2012).

Depeche Mode, Delta Machine, Columbia Records/Sony Music Japan SICP-3783-4, FLAC 24/44.1, source: HDTracks (2013); reviewed HERE.

Miles Davis, Tutu, Warner Brothers Records, FLAC 24/96, source: HDTracks.

Persy Grainger, Lincolnshire Posy, Dallas Wind Symphony, Jerry Junkin (conductor), Reference Recordings, HR-117, HRx, 24/176.4 WAV, DVD-R (2009).

Sonny Rollins, Tenor Madness, Prestige, WAV 24/96, source: HDTracks (1956/2012).

Stan Getz & João Gilberto, Getz/Gilberto, Verve, 24/96 FLAC, source: HDTracks (1963/2012).

Stardelay A New High Fidelity, Ozella Music OZL22006CD, FLAC 24/44.1 source: Linn Records (2008).

In addition to the previously mentioned size-related sayings, there is another one in the audio world that can be summed up this way: it sounds the way it looks. In other words, if it's small it sounds small and if it's big it sounds big. While at first glance the notion that the outward appearance should affect the sound may seem absurd, on further reflection, knowing the reality of audio products design, we will admit that there is something to it. If we want an amplifier with a high output power or at least high current efficiency (to provide large phantom images and volume), we need a large transformer and even larger heat sinks. The only exception is Class D amplifiers. Preamplifiers and DACs face similar requirements relating to their power supplies. If the speakers are to reproduce low bass and their presentation offer a large volume of sound they need a big woofer. I must say that although I'd rather be wrong and not build my knowledge on such—at first glance—esoteric foundations, small components do sound small and large components offer a large sound. The latter is not everywhere and not always true, but it is common in the case of miniature components. And that's why in what Thorsten Loesch did in this regard, I see his uncanny sense of musical material, as I assume that his components design and the resulting sound is his merit.

iFi Audio Micro iUSB POWER iDAC and iCAN

I began the review by connecting the iCAN to my reference system, or in other words plugging a midget into a giant (in terms of both size and price difference). What I heard was very satisfying. It was so good that I could focus on music and on how it was presented as such, without trying to deconstruct the sound. It was possible to fairly quickly verify the converter's quality and just as quickly come to the conclusion that those who preach high-end for the buck don't know what they're saying. Only that this is not the point as comparing the IFI components to swanky products costing a fortune is not fair and does not make any sense. What is most important in all this often gets lost: I don't think young people and generally those who use audio systems based on a PC as a source have ever had access to such good sound (assuming of course that they don't want to spend more than 10,000 zlotys per component). All previous attempts were cool, successful and interesting. Yet here for the first time I heard something plugged into my mega-expensive reference system that, while clearly disclosing its own weaknesses, offered the kind of sound I could happily live with.

The iFi's presentation was based on panache, a well-judged tonal balance and micro-dynamics as well as a perfectly captured relationship between selectivity and resolution. The panache was reflected in building a large and expansive soundstage. It was mostly located behind the speaker line, and the counter-phase effects were not localized too precisely. Nevertheless, the size, breath, panache and a seeming lack of restrictions on the ability to convey the size of instruments (or actually their phantom images, but let it be) were above average and beyond what many expensive, full-sized components can do. The iDAC will provide real fireworks at our home, which will be particularly appreciated by all those who have their speakers placed on a desk, close to each other. They are in for hearing a real soundstage, as if they discovered it for the first time in their life. Everything they've heard before will seem to be its shallow imitation, fake in comparison.

Everything was also in its place tonally-speaking. The low bass on Assemblage 23 and Dead Can Dance recordings was conveyed with authority and power. If looked at closer, its very bottom was not particularly strong and not as well-controlled as with expensive DACs and digital/CD players. It's just that such poking one's nose into it didn't make sense here. The whole presentation was consistent and logical, with one thing resulting from another. And, for example, the other end of the frequency range was a reflection of what's going on at the bottom—there was the panache, nice color, lack of distortion or coloration and a good separation.

iFi Audio Micro iUSB POWER iDAC and iCAN

Compared with something expensive, though, iDAC's highs may have seemed somewhat withdrawn and concealed behind the rest. Not so much behind the midrange but perhaps generally behind the presentation. Usually, a weaker treble automatically promotes midrange as it seems to highlight and bolster the vocals. This can also help to improve vividness—if there's less information in the presentation, what remains has more weight. Thorsten Loesch has chosen another way. It quickly turned out that all sub-ranges were even, which was even better brought out by connecting the iUSB Power. It's actually difficult to talk about particular sub-ranges, as there wasn't a point where something would be weaker or stronger. Still, there was a feeling of a weaker treble. In my opinion the problem was in the tangibility of sound, in building 3D textures with rounded surfaces and depth. Or perhaps it's not what I meant—it's not a problem that affects iFi's reception in terms of its relative quality, dependent on its price. In this respect, it is at least as good or even better as other manufacturers of such (micro) components. The problem relates to the absolute evaluation, with the iFi compared to the best available products. And that's probably the most important difference between the high-end and the products from Thorsten Loesch's stable. After placing them in their natural environment, in a computer system, it is drastically minimized. Still, their quality can be further improved, which has been taken care of by the manufacturer itself.

iDAC + iUSB Ppower

The effect of power supply on the sound is known and easy to measure and explain. It is much more difficult to apply it in practice. The issue has already been recognized and worked out in classic audio products and the efforts exerted in this direction and the accepted compromises seem to have been successful. Computer audio has proven much more of a problem. This is the area dominated by computer-oriented companies that manufacture computers, sound cards and other peripherals. They employ a kind of "digital is digital" approach even including power supply. A noble exception seems to be Asus with its Xonar Essence One converter and the cheaper Xonar Essence STU I'm just listening to, which demonstrate what happens after combining the production capabilities and knowledge of computer experts with audiophiles' expertise and practice. That's an exception, though. Tests aimed at improving the quality of power supply indicate how deeply mistaken other companies are.

iFi Audio Micro iUSB POWER iDAC and iCAN

What changes the rules of the game is replacing the computer PSU that powers the USB receiver chip in the D/A converter via the USB cable with an outboard power supply coupled via a dedicated USB cable and thus feeding the DAC with a dual-headed A → B USB cable.

As I said before, the upper treble seemed hidden behind the presentation. I had no problem with that, especially in the computer system (see "Testing methodology" above), and it only attracted my attention in the reference system. Hooking up the outboard power supply showed what was going on and why I was missing anything. The tonal balance remained unchanged. It's not that the extra power acted as a filter or equalizer. Something else was happening. The instruments took shape and filled with content. The somewhat less clear 3D I mentioned before was now markedly improved. The presentation was more tangible with phantom images more vibrant and natural in their mass, weight and energy. Macro-dynamics was better, too. Micro-dynamics was surprisingly good even earlier, resulting in the sound that was lively and inspiring (to further auditions). Macro-scale dynamics, however, was rather averaged, at least in comparison to expensive components from other manufacturers. Now it was improved to a similar level. The iFi still seemed to me somewhat calmed, at least where it needed to show the true scale and power of music, irrespective of its style. And yet, by imparting a real body to the events on the soundstage there was nothing to worry about, which left me more than satisfied and happy.

The iDAC is absolutely sufficient when used on its own. I think that swapping what one has at home for the iFi DAC brings a qualitative change enough to last it a long time. Adding the iUSB, however, will give it a kind of imprimatur and push it even further. And it will be heard irrespective of the system in which we use these components.


Whether on its own or in duet with the iUSB, the iDAC is an essential component in any computer system. Without it we are left at the computer sound card's mercy. The iDAC quality is so good that it allows us to forget about other solutions which no longer make sense in this configuration. It could be done differently, using DACs from NuForce or Hegel, but would it be necessarily better? I'm not quite convinced. The role of the iDAC in the system, however, does not end in converting the USB digital signal to analog. Its front panel features a headphone mini-jack next to the volume knob. This is not a "switching jack" that disconnects the RCA line output when a plug is inserted. The iDAC can thus be used as a headphone amplifier. It will prove most satisfactory in that role, provided we don't use our headphones too often and are not their biggest fans. However, if that's how we listen to music on a daily basis and have decent headphones, we will need to buy an external amplifier, such as the iCAN.

iFi Audio Micro iUSB POWER iDAC and iCAN

It sounds large and lively, similarly to the iDAC. Its user-selectable gain can be adjusted to match the headphones. The machine is dynamic and strong, and has a very nice bass – but only with the XBass switch on. I used the latter in the intermediate position with the majority of headphones, but I see no problem for people who like energy and power to go immediately for the highest level. Equally important was the 3D HolographicSound. As I'd already known it from my experience with the iTube, my reaction wasn't so spontaneous and I resorted to nodding my head. What these two functions bring in can be considered spectacular. The sound doesn't really sit in your head and is fleshy. The treble has a nice, creamy color, but is quite abundant. That was why pairing the iCAN with the HE-300 from HiFiMAN, while great in terms of dynamics, space, and bass, was not exactly in line with the objective truth. But the fantastic AKG K3003 and AKG Q460 from the Quincy Jones line sounded in a very balanced, controlled manner.

iFi Audio Micro iUSB POWER iDAC and iCAN

The iCAN will easily satisfy all those who don't want to spend more than 2,000-3,000 PLN on a headphone amp. There is no momentum and depth of the Leben C300 XS [Custom Version] and the Bakoon HPA-21, but I never suspected it anyway as other amplifiers can't do it either. What the iCAN does give is a freedom of sound, excellent space and a good tonal balance, except perhaps for a pretty strong treble. The latter can, however, be controlled by a judicious selection of headphones.


Thorsten Loesch has his audio components manufactured in China. I envy the Chinese for their ability to do something like that. It's top of the line, world class stuff on a par with Apple whose products are in fact manufactured in similar plants. It actually seems that the iFi packaging comes from a nearby, if not in the same, factory as the packaging of the iPad line. The sound is spectacular. Nothing less, nothing more, period. Or maybe I'll just say: Thorsten, you have a unique feel and taste!

iFi Audio Micro iUSB POWER iDAC and iCAN


Computer audio products are usually on the small side. Aimed at young people who don't understand that high-end audio products are large and heavy, they need to fit on their desks and tables. Housing high-end electronics in stylish, sleek enclosures imposes special requirements on manufacturers that recognize the importance of sound quality. The idea for such products, at least when it comes to their style, has been rehearsed by many companies. Thorsten Loesch simply adapted it to his needs and took care of the details that usually go unnoticed by others. The packaging resembles Apple product boxes. The flat enclosures are made of aluminum and measure just 168 x 67 x 28 mm. Their weight varies between the components but falls below 300 g. They are aluminum extrusion profiles slotted internally for PCB mounting, with front and rear panels mounted on both ends. Small rubber feet are added to prevent from sliding. However, since the components are very light, a slightly stiffer cable is enough to lift them. In my opinion it wouldn't be out of place to think of a support system to integrate them all. Choral Modular equipment supports from British Chord Electronics are among the prettiest.

iUSB Power

This concept is known from other manufacturers, such as KingRex (see HERE) and Elijah Audio. One panel of the iUSB Power features a Type B (square) USB input, an external power supply socket and a toggle switch. The other end panel sports two Type A (longitudinal) USB ports to run separate power and audio data lines. Power is provided from a 9V DC external wall-wart adapter. I wouldn't be surprised if there was soon a new, battery powered product in this family. The toggle switch mentioned above cuts off the signal ground from the chassis—this solution is called IsoEarth. The manufacturer claims that it reduces ground noise by 20dB. It is recommended to always use it, except when the computer has data sync problems. The top panel sports three micro-LEDs that indicate power and IsoEarth on/off and computer connection (USB source).

The system is mounted on a printed circuit board with gold plated traces and SMD components. It is very precisely laid out so it can be easily seen that the circuit is a three-step, 6th order analog filter with coils, chokes and isolating transformers. Voltage stabilizer is based on integrated circuits and the reference voltage circuit on a transistor.


The iDAC is a USB D/A converter, or in other words a DAC that sports only one input—a USB port. It is placed on one panel, while the other end panel sports stereo analog RCA connectors (non-gold plated and placed close to each other), a headphone mini-jack (3.5 mm) and a volume knob controlling headphone output. The top panel sports three green micro-LEDs, indicating signal transfer, computer connection, and power on/off.

iFi Audio Micro iUSB POWER iDAC and iCAN

The electronic circuit is mounted on two circuit boards—one houses the USB receiver and I2S converter, and the other the DAC and headphone amplifier. The receiver is based on the popular XMOS SK1215L1 chip, working asynchronously with the USB signal up to 24-bit and 192kHz. The manufacturer calls it "24/192 Bit-Perfect Asynchronous USB Module". Next to it are three very nice master oscillators. One clocks the USB receiver, and the other two are for the already converted signal, each for the 44.1 and 48kHz sampling-frequency families: 22.5792 MHz and 24.576 MHz (Fmclk). The manufacturer calls this solution "Ultra Low Jitter Master Clocks". The PCB evidently comes from another device. It is connected to the DAC PCB with gold-plated pins. The DAC chip is of the highest quality—the ESS Sabre Hyperstream ES 9023. It combines a digital receiver, digital filters, DAC and output circuitry. That's why we have a single output stage on surface mount transistors. Before the headphone output we can find a single Maxim Integrated MAX9722 chip. It operates in DirectDrive mode, i.e. without any coupling capacitors.

Specification (according to the manufacturer)

  • Signal to Noise Ratio: > 111dB (A)

  • Dynamic Range (-60dBFs): > 111dB (A)

  • Crosstalk: < -102dB (1kHz)

  • Total Harmonic Distortion (THD): < 0.005%

  • Jitter: Below measurement limit

  • Frequency Response: 3Hz to 33kHz (+ 0.1dB/0.3dB)

  • Headphone section:

  • Output Power: > 150mW (15Ω)

  • Output Voltage: > 3.3V (> 100Ω)

  • Signal to Noise Ratio: > 97dB (A) (400mV/300R)

  • Total Harmonic Distortion: < 0.003% (400mV/300R)

  • Output Impedance (Z out): < 1Ω

  • Power Consumption: < 2.5W

  • Dimensions: 158(l) x 68(w) x 28(h) mm

  • Weight: 193g (0.43lbs)


The front panel features no less than four manipulators: a volume knob, a three-position XBass switch ("Direct", powerful bass and medium bass), a three-position 3D HolographicSound switch (large space, "Direct", average space) and a 6.3 mm headphone jack. The latter features no coupling capacitor (DirectDrive). On the rear panel we have a socket for the 9V DC wall-wart power supply, stereo RCA line input and a 3.5 mm input jack.

The circuit is mounted on a single PCB with gold plated pins that houses both audio circuit and a complex, multi-stage power supply. The gain section is called by iFi "Class A TubeState amplification." The idea is that the initial gain stage is on single transistors operating in class A, connected in a simple circuit similar to those used in tube amps. The headphone output is fed from a single TI 6120A2 buffer and amplifier chip. The headphones are connected without coupling capacitors, with small coils made of PCB traces in their place. 3D HolographicSound and XBass filters use good polypropylene capacitors. The headphone section has three gain stages: 0dB (normal), 10dB and 20dB. The latter will drive even planar headphones.

Specification (according to the manufacturer)

  • Gain: 0dB, 10dB and 20dB user-selectable

  • Signal to Noise Ratio: >117dB (A)

  • Total Harmonic Distortion (THD): <0.003% (400mV/150R)

  • Frequency Response: 0.5Hz to 500kHz (-3dB)

  • Output Power: >400mW (32Ω)

  • Output Voltage: >5V (>600Ω)

  • Power Consumption: < 4W idle, 10W max.

  • Dimensions: 158(l) x 68(w) x 28(h) mm

  • Weight: 216g (0.48lbs)

Abbingdon Global Group

Price (in Poland): 889 PLN | 1,349 PLN | 1,089 PLN

22 Notting Hill Gate; London; W11 3JE; United Kingdom;
+44 (0) 870 420 5505

Country of origin: Great Britain