For some the iFi Audio micro iUSB3.0 as reviewed here and its ilk is a controversial device. I'll accuse it of having a mouthful of a name but otherwise for myself it's not controversial at all. This is another Swiss Army Knife from iFi Audio; I previously reviewed another multi-purpose device – the iFi micro iTube whose functions are multi-faceted as it's a buffer or preamp depending on how you configure it. The iFi Audio micro iUSB3.0 is useful for computer (file-based) audio using an external DAC connected via USB. This covers the vast majority of lossless computer playback in hi-fi systems. This latest Swiss Army Knife improves on the functionality and performance of the original iFi micro iUSBPower.
The iFi Audio iUSB3.0 reviewed here uses a number of methods to do two fundamental
That all sounds fine and dandy but a trawl around some of the HiFi forums will reveal a small but very vocal contingent who espouse that "bits are bits" and nothing special is needed for digital playback. Some seem blinded by 0 and 1 being simple and incorruptible but is a hi-fi system really that simple? Unfortunately not. Yes USB is wonderful for transferring files to a printer and I don't see people saying that files are corrupted when transferred over USB, but playing music is not like printing a document. There is scope for electrically noisy computers infecting the ground plane of the downstream DAC, not only is the ground noisy but the +5V supply will be quite unpleasant too. Noise on the DAC ground plane may not impact the digital section of the DAC but DACs have an analogue section too; this is not somewhere we want to inject noise. Even if your DAC is not USB powered or does not use USB power for its USB card, there's a good chance the DAC ground will still connect with the USB ground. A clean ground is goodness. Then we have the re-clocking and general cleaning up of the USB data stream. We're not talking about correcting any data errors but instead this is about making the data easier for the DAC to handle and getting the electrical impedance right. Bear in mind that the data (music) you're playing from your computer transport does not carry timing information; this is something the DAC has to figure out. It seems that regenerating clean data helps a good number of DACs.
I'm in the camp that believes the software player used has a profound effect on the sound I hear. I wish this weren't so, I really do. Computers are horribly noisy things and it seems that software players can alter the sound we hear by using simplified render loops and very specific instructions from the machine's instruction set. This is a massive topic but I have heard the effects with my own ears. The absolute fix for these playback issues is to build a special purpose computer with linear power supplies and running a cut down operating system. Some use the Raspberry Pi which is quite decent but can be bettered by Windows players such as Jplay and the Japanese Bug Head. The world is not ideal; we don't have easy and low cost access to high quality streaming hardware though I daresay this will come along. In the meantime those of us not into building our own hardware can reap huge benefits from using specialist playback software and using the likes of the iUSB3.0 to clean up power and data over USB. Whilst iFi use a switched mode plugtop power supply called the iPower they take a lot of care to ensure it is quiet and then they work on filtering the power yet more, they say they have achieved a very quiet 0.1uV, which is extraordinarily quiet.
This box of tricks also implements iFi Audio's IsoGround which can be selected to be Off or On, this is optionally breaks the ground connection to the computer in a way that is USB standard compliant. Talking about standards, iFi are embracing USB3, this device is fully USB3 compliant and well as being fully backwards compatible with USB2. A short USB3 cable is provided with the unit, this again will work with USB2 as well. There is also a power mode switch, this controls the power from the iUSB3.0 such that it can switch power on/off in synchronization with the PC or it can permanently powering its USB port so for example a battery powered DAC can be left on charge. The outputs of the USB3.0 follow iFi's previous practice, there is an output with just the power lines connected and another with data + power, this allows cables such as the iFi Gemini to used where the power lines are in a physically separated cable to the data cables, this I find has benefits presumably due to reduced transfer of noise between power and data lines. Not only are there a pair of power and data ports, there are two of each so you can connect network attached storage and your DAC via the USB3.0. You could even run two DACs or a DAC and charge your phone.
Does The iFi USB3.0 Live Up To
1. iFi Audio iDAC2 – this an iFi USB powered DAC meaning that the digital and analogue sections take their power from USB. Even with iFi's excellent power filtering I would expect any remaining noise to have audible effects.
2. Metrum Octave MKII – this DAC has its own linear power supply for main DAC but the USB card is powered by the USB, there is significant USB power filtering in the DAC and there is also galvanic isolation implemented. I have previously found this DAC to respond very well to an iFi power supply feeding the internal USB card, especially in terms of bass performance.
3. Ciúnas – this battery powered DAC by John Kenny is an excellent performer, it takes no power from the USB, instead it uses internal LiFePO4 batteries.
iFi Audio iDAC2
I started out with the iDAC2 powered by my laptop USB. The DAC certainly sounded good, this was no surprise given the editor's recent review of the DAC. Compared with the original USB powered iDAC I felt the iDAC2 was a considerable step up. This suggested that the DAC has been significantly improved, part of this is bound be down to the latest iFi experience and developments around implementing highly effective filtering of what is invariably very noisy USB power and electrical ground. I should mention that I mostly used the DAC is set to Bit Perfect mode which means it operates as a Non-Oversampling (NOS) DAC.
Next I introduced the iFi Audio iUSB3.0 and iFi Audio Gemini USB cable. It was immediately apparent there was more inner detail; low level sounds deep in the mix were much clearer and more easily distinguishable versus being lost in the mix. The sound was more open with a greater sense of ease. The bass if anything exhibited a lighter touch but importantly listening to bass notes plucked on a double bass when were adjacent to each other on the musical scale, it was now possible to properly discern the individual notes rather than their merging into one amorphous sound. The soundstage had opened up too, previously hi-hats had been locked to the tweeters left and right, now they were floating properly between the speakers.
All-in-all I'd say the iFi iUSB3.0 with matching Gemini USB cable adds palpability to music making the iFi iDAC2 more sophisticated. It certainly makes the iDAC2 sound like a much more expensive DAC.
Metrum Octave MKII
I had to try one last thing with the Octave; the iFi Audio iDAC2 has an S/PDIF output so it can act as a USB and S/PDIF converter. Running the iUSB3.0 into the iDAC and then feeding SPDIF to the Octave resulted in the best of all worlds. Where the iDAC2 has been so good, so was the Octave and where the Octave scored with its breathy sax victory this too was retained. I have a sneaking suspicion these successes are down to the iFi implementation of the XMOS USB interface and the iDAC2 handling of the digital signal.
I used the REGEN via the Octave DAC to set the initial standard as this is what I have been using and was very familiar with. The tricky part of this comparison is that I can't differentiate between improvements due to the linear power supply with the REGEN vs the re-clocking functionality of the REGEN. Prior to using the REGEN I used the original iFi iUSBPower, which does no re-clocking.
I use a couple of different open baffle speaker setups, one is more forgiving of poor recordings, the other is more "explicit" sounding. With the forgiving open baffles it's hard to detect much difference in sound between DAC+iFi Audio USBPower (the original iFi Audio power device) and DAC+Regen. With the explicit sounding open baffles it's easier to pick up on what REGEN brings; greater clarity, more natural sibilance, cleaner upper treble (hi-hats and tinkly sounds), there's greater separation and delineation between sounds. Bass is a little tighter and therefore subjectively a touch leaner too. Trumpet and piano are smoother too.
How Important Are The Improvements
Brought By The REGEN?
The REGEN was my baseline for auditioning the iFi Audio iUSB3.0. I tried all three DACs – iDAC2, Octave and Ciúnas with both REGEN and iUSB3.0. The result as the same each time though to differing degrees. The iFi Audio USB3.0 gave a richer and smoother sound with fine detail presented in a less forced manner. Bass with the iFi was mostly more powerful, there was also slightly better central focus. Listening to Wynton Marsalis' trumpet on his album with Eric Clapton I found Wynton's trumpet a trace sharp with the REGEN whereas the iFi made this difficult instrument sound more balanced. The REGEN gives a slightly "etched" sound versus the iFi iUSB3.0. The REGEN certainly brings improvements but the iFi offers further improvements.
To Re-Clock Or Not?