This nifty little device will allow output of up to 24-bit/192kHz S/PDIF from a USB port. The hiFace looks a bit like an oversize USB flash drive with an RCA or BNC connector on the opposite end. Using a USB device allows one to employ a much smaller and easier to cool computer and I ended up with a "nettop" class of machine. This is much like the netbook laptops using an Intel Atom processor and a 2.5-inch hard drive. Passive heat sinks are enough to provide cooling without fans and the small hard drive is very quiet and inaudible from my listening position, avoiding the expense of a solid state drive. Unfortunately most of the USB devices, either DAC or S/PDIF output do not support the highest resolutions available and often use the PCM2702 from Texas Instruments, which is limited to 16-bit/48kHz. There are some very nice USB DACs available from Ayre Acoustics and Wavelength Audio to name a few but for the low budget audiophile like myself they are still a stretch of the wallet.
The M2Tech hiFace operates asynchronously with two high precision clocks covering the multiples of 44.1/88.2/176.4kHz and 48/96/192kHz. These clocks have a claimed precision of 2.5 ppm and very low phase noise. The use of a high performance transmitter allows the output to have extremely low jitter and M2Tech employs a pulse transformer to provide galvanic isolation from the computer. At this time M2Tech offers drivers for both the Macintosh and Windows operating systems. Linux support is forthcoming. Since my day job is working with Windows based machines I don't have any experience with the Macintosh version and look forward to giving it a go under Linux once the drivers are available.
The hiFace is primarily designed to use kernel streaming under Windows, regardless of version. This ensures low CPU utilization even at high bit depth and sampling rates and allows for a highly optimized driver. M2Tech supplies proprietary