Sutherland 12dAX7 USB DAC and Preamp Reviewed

Published On: January 4, 2009
Last Updated on: October 31, 2020
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Sutherland 12dAX7 USB DAC and Preamp Reviewed

Using 12 AX7 tubes this USB-only DAC has its own analog volume control so it can be used without a preamp. Using true dual-mono construction throughout, the 12dAX7 USB DAC brings PC audio up to a level that's competitive with stand-alone transports.

Sutherland 12dAX7 USB DAC and Preamp Reviewed

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Sutherland_12DAX7_USB_DAC.gifIn the hierarchy of people who actively pursue cruddy sound, the top spot belongs to computer nerds. Who else voluntarily puts up with sonic nightmares so gleefully, while having the audacity (in their techno-arrogance) to declare that the swill from PC soundcards via £29-per-pair plastic boxes is good because it's 'digital'? Arguing is pointless: most new music has more in common with Intel and Motorola than Fender and Steinway. So, in their sheer lack of discernment (or, more likely, utter meanness), nerds perpetuate the acceptance of bad sound. All of which bodes ill for what could be their salvation.

Ron Sutherland, who released a line of cutting-edge solid-state amp and pre-amps in the 1990s, offers a product which bypasses a computer's soundcard and accesses the digital data stream directly via a USB socket, as found on nearly every post-1998 PC and some Macs. The inspiration is simple: computers are overtaking hi-fi in certain quarters (e.g. colleges) as the source of music, yet they suffer undernourished power supplies, most sound cards are made from scandalously cheap parts, and the environment in which they operate is 'dirty'. More specifically, because volume control in a computer exists in a purely digital domain, the software 'volume sliders' lower level by shedding bits of information. The 12dAX7 adjusts volume solely in the analogue domain, with no loss of information.

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Unbelievably given Ron's pedigree, the 12dAX7 is a valve product. And we all know that the digitisation of music adds vile artefacts to the signal; the 12dAX7 uses 12AX7 tubes in a special circuit that 'euphonically restores even order harmonic structure to music.' Each channel in the 12dAX7 contains its own circuit board, 'a type of dual-mono construction unusual in even the most expensive high-end audio products,' according to Sutherland. And Sutherland chose a Burr-Brown PCM2702 DAC as the heart of the unit.

Effectively a preamp-D/A converter housed in a gorgeous 15x8.5x3in (WDH) box to fit in-between computer and hi-fi system, the 12dAX7 is so minimalist that it doesn't even provide on/off; the unit is controlled entirely by the computer to which it's attached, save for a master volume rotary on its 1/2in thick Perspex front panel. Through the panel, you can observe the valves and four LEDs on the PCB: 'mute' which flashes red during warm-up, 'suspend' (also red) which is on until the computer drivers 'find' the 12dAX7, a yellow LED marked 'zero' which glows when there is no audio data coming in, and 'play', which glows green when digital data is available. The back contains only the USB input, phono sockets for left and right analogue line output and an IEC mains socket.

Its cold-rolled steel chassis houses high-strength fibreglass PCBs
for the power supply circuit board, the DAC module and the two valve
gain modules. Parts include a pair of easy-to-replace Russian 12AX7
tubes, Dale 1% metal film resistors and Wima polypropylene film
capacitors, so audiophiles should feel right at home. The Sutherland 12dAX7 uses a
toroidal power transformer.

In 15 years, I have installed over 300 programs or pieces of
hardware, using USB exclusively since Windows 98 made it worthwhile. I
swear: no single product - not from Iomega, Norton, Hewlett-Packard, and
certainly not from Microsoft - has worked so perfectly from initial
insertion. And I didn't even have the dedicated software! I just plugged
it in, my PC found it as a "USB Audio Device", and seconds later,
sounds emerged from the 12dAX7.

Given that I have NEVER employed my CD-ROM drive to play CDs because
there's a Musical Fidelity X-RAY on my desk connected to a Marantz 1060
integrated amp and a pair of Spendor LS3/5As, music playback through my
PC is limited to CD-Extra elements on music CDs. Even so, my PC is
cluttered with MP3 and WAV files and other stuff which I usually access
through Windows Media Player and other programs. And then there are the
games which now boast killer soundtracks, webcasting and more.

Clearly, the 12dAX7 renders the PC's sounds more acceptable to
audiophiles, music so sweet, coherent and wideband that the
CD-ROM-plus-12dAX7 came remarkably close to the X-RAY when used with
conventional CDs. MP3 and WAV files were richer, cleaner and quieter,
with far better imaging and vastly-improved dynamic range. The CD Extra
video of the First True Pop Classic of The New Millennium, Wheatus'
'Teenage Dirtbag', came perilously close to the sound quality of the
same video on Region DVD of . (Note to Mactossers: the MPEG version MASSACRES the QuickTime!)

I will never, ever use my Soundblaster again.

But an open letter to Sutherland: please, please add on/off to the
volume control for those who leave our PCs on all the time (and it may
be necessary for CE approval), and add just one conventional digital
input. Then the 12dAX7 would be a proper digital pre-amp, infinitely
more flexible and therefore more appealing. Y'see, this magnificent,
milestone device deserves to be heard by anyone who has converged his or
her PC with an audio system, say, those who want to play Quake 3 on
their 50in plasma screens through their surround sound systems. The days
of utterly cruddy PC sound are over. And amen to that.

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