M2Tech HiFace USB – jkeny modded

Francis Morrin

I’ve had some very interesting listening here over the last few nights. John Kenny called over with his modded HiFace USB-SPDIF gadget for me to have a listen and to review. For those of you who haven’t seen this unit before, this “gadget” just plugs into your PC/laptop whatever and will output SPDIF for connection into your DAC.

Up until recently, the only chips really available to do this were the PCM2707 family from Texas Instruments. They were limited to 16 bit at 48khz (in other words DVD-A). It has long been known that both USB and SPDIF can carry much higher sample rates, but the big problem were the availability of drivers for windows, Mac and Linux. In other words, if you plug the DAC in, windows will recognise it as an audio device and send the signal out through it. The TI chips use the native Windows USB drivers – a true plug and play solution. So given the rise of computer/HDD audio there is now higher interest in getting better sound out of these chips. The problem has been getting the drivers written to control the FPGA chips that can be custom driven to accept the higher sample rates. Gordon Rankin of Wavelength has had a version available for a while now, but at serious cost. Now 2 more companies have cracked this nut, one from China who made the Musiland device for an amazing €80 and the HiFace from M2Tech in Italy for about €120 or so. In each case there are custom written drivers that will need installation in your PC or laptop.

So, what has John done with the HiFace unit? Well, the mods revolve around improving and/or replacing the power supply. As standard, the unit draws its power from the USB connection in your PC or laptop. But this is a noisy (electrically) environment with many different devices drawing varying and sudden amounts of power. As the chips use this power supply as their reference baseline, the quieter and more stable these supplies are, the better sounding the device. John’s mods isolate the power supplies to the key chips and replaces them with battery power. But not any ordinary battery – these are rechargeable lithium polymer ion batteries which give very stable voltage right until they are discharged, and are capable of huge current supplies when called upon – there are videos on Youtube of 4 of these starting a car (- youtube link here)! Another modification that John advocates is to separate the 5V supply to power the rest of the unit (done via a modified USB cable that John can provide). This power normally comes from the USB directly. Other options are also open instead of batteries, but whatever is used better be the best, most stable and quietest power supply available.

So how does the unit sound? Well in a word excellent! There is a clarity to the sound that is quite remarkable – you really notice it at the frequency extremes. Bass is incredibly tight and well defined and treble is smooth and clear without any trace of harshness. Massed violins, or recordings with some sibilance are actually quite listenable. If you had any doubts, a quick reversion to a PCM 2707 based converter will re-assure you. John himself told me how he noticed ever-increasing levels of clarity in the sound as he worked his way through his mods to the HiFace, and I for one believe him. As John himself says “I now know what jitter sounds like – as each improvement was implemented a layer of hash and noise was removed and bass and treble improved. However, go back and compare to a standard unit and the difference is pretty stark”.

Extended listening with the HiFace also showed up a superb depth of soundstage, sounding really fantastic with all music, and especially effective with full orchestral music. Given a DAC of adequate quality (and I do believe that Johns modded HiFace unit will only reflect what the DAC can handle) the sound has a liquidity and pace that does compare to analogue. As a testament to its resolution, I could clearly hear the difference in music files encoded to different sample rates, all the way up to WAV files. Not many transports can do that.

I compared the Hiface to my own standard, a modified transport similar to the 47 labs shigaraki transport. I used primarily my Buffalo DAC, based on the Sabre reference 9008 chip from ESS technologies. I also did some listening with my Pass D1 clone. The rest of the amplification chain was a symmetrical B1 preamp and Pass F5 amplifier, with my Sachiko horns on speaker duty. The system is pretty unforgiving, very revealing and ruthless with harsh or edgy material. I also had a less thorough listen with my Pass D1 when I brought it to a friend’s house and had a listen using his Airtight EL34 amp and Quad ESL 989 speakers. In both cases the results were the same.

So, what are the downsides? Well, you need batteries, and then a way of recharging them, or else as mentioned above, provide some other high quality 3.3V power supply to the unit. Of course, you also need a DAC that you can feed the SPDIF into – and this DAC will be just the first link in the chain that will determine how good your system as a whole sounds. Ideally it would be capable of taking 24/192 recordings to fully exploit the capabilities of the HiFace. But, for those who have a good DAC but whose transport is aging, or if you need to free up some space and get rid of a few thousand CDs, there is now a viable PC/laptop/HDD solution to a really good transport. Also, when using Johns prototype, we noted that the power up sequence on connecting the various supplies into the HiFace did matter – one DAC would not lock to the signal unless powered up in a specific sequence, but once we got that nailed, there were no problems subsequently. When I got to thinking a little more about this unit and the possible system configurations possible, it seems obvious that a small but dedicated PC might be a good way to go. Something like a tablet PC or netbook and a big external HDD would provide a very nice interface, very like the Sooloos system but at a fraction of that cost. Such tablet PCs/netbooks are available secondhand for EUR100-300 or so, and even Apple’s brand new tablet only recently released retails at around the EUR500 mark (although I believe that this does not have a USB output). A slightly larger system could use a shuttle PC, also available from about the EUR150 secondhand, but you would then need a screen, keyboard and mouse. Add to all that a whopping big hard drive to allow you to rip your CDs in WAV format. If you want to conserve space, maybe go to FLAC format, but John is convinced he can hear the difference and only advocates WAV. As such storage is now cheaper than ever, he may well have a point.
As I finish writing this, I start to think about how non-DIY users would find this unit. Many would find having to charge batteries an issue – but few have problems charging their mobile phone on a daily basis. I suppose a bigger issue is having to disconnect and reconnect the batteries. The completely ham-fisted could somehow force the connections in the wrong way around, but very small amounts of care would prevent that ever happening. Also, the batteries last quite a long time between charges, often up to a week depending on usage. I would also like to note that the pictures shown here are of Johns own prototype, so it is a bit rougher than normal, and also the standard modded version does not have the open DIP-8 socket on the top of the unit. Other than that, installing the drivers was easy (tried on both XP and Vista 64 bit) and the unit was picked up with no problems on both systems. After that it was a case of relaxed listening on easy street.

jkeny can be contacted at john.f.kenny@gmail.com

Ancillary equipment:
A variety of music files in WMA, FLAC, WAV and MP3 format, virtually all at 16/44 resolution.
“Shigaclone” DIY player based on the 47 labs Shigaraki transport
Pass D1 DIY dac
Twisted Pear Buffalo DAC with discrete output stages
BNC cabling for digital, Silver plated copper ICs and speaker cables
Pass DIY symmetrical B1 buffer (DCB1)
Pass DIY F5 amp
Sachiko horns with modded FE206e drivers.