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This review first appeared in the December 2011 issue of hi-end hifi magazine of Germany. You can also read this review of the ARC DAC8 in its original German version. We publish its English translation in a mutual syndication arrangement with the publishers. As is customary for our own reviews, the writer's signature at review's end shows an e-mail address should you have questions or wish to send feedback. All images contained in this review are the property of fairaudio or ARC - Ed.

: Jörg Dames
Sources: Fonel Simplicité, laptop w. foobar2000/J River MC, Northstar USB dac32, Benchmark DAC1 USB
Amplification: Fonel Emotion, Abacus Ampino, Funk MTX Monitor V3b, Audionet AMP Monos
Loudspeakers: Thiel CS 3.7, Sehring S 703SE
Cables: Straight Wire Virtuoso, Vovox, HMS Fortissimo, Reson LSC 350
Power: Quantum-Powerchords, Hifi-Tuning Powercord Gold w. IeGo termination, MF-Electronic power strip
USB: Monster Advanced High Speed
Rack: Lovan Classic II
Review component retail: €5.400

Some think there’s nothing new under the hifi sun. I rather feel that change has been spread wide. And that's not merely by way of real advances in affordable loudspeakers. Consider valve stalwart Audio Research. They have embraced not merely class D amplifiers but released a 100% tube-free D/A converter whose main design goal was USB which the Americans feel offers the greatest sonics of all their interface ports. Their DAC8 also dines on S/PDIF via coax and BNC, AES/EBU and Toslink with one input each. 24/192 compatibility spans the gamut. The drivers on the CD/ROM are needed only for Windows users of USB. A remote too is included though there’s no volume or variable output to have this machine replace a traditional preamp. There’s arm-chair command over input selection, mute and absolute polarity plus one function I personally find very helpful even though the manual only makes casual mention of it.

In USB mode the remote can also control an associated media player—J.River and Foobar2000 worked like a charm—with next/previous, play/pause and stop. Since either player can be set to make the current track visible on a laptop screen even from quite the distance, this neatly circumvents the need for a smartphone plus App & Co. if your needs in that sector don’t exceed the functionality of legacy CD players. With the basics covered, let’s take a closer took at the machine and also how to optimally configure media players and drivers. The DAC8’s XLR outputs aren’t mere convenience but the entire circuit is built up symmetrically inclusive the converter chips which in the DAC7 still worked in stereo mode. The 8 gets a total of four (two mono DACs per channel) which the developer claims drives down S/N over the predecessor by 3dB  and improves channel separation.

Aside from the four DACs—quad converter design in ARC speak—the Americans went twins also with two master oscillators where the older DAC7 just ran one. This dedicates each clock to just one sampling-rate family—44.1 and its familiars of 88.2 and 176.4kHz; and 48/96/192kHz—to minimize math and with it decoding and quantization errors. But the user will never notice any of this. The machine automatically recognizes the incoming sample rate to switch in the proper oscillator.

The DAC8 eschews a conventional display to confirm the sample rate and selected input via glowing diodes. The USB path naturally offers user-selectable upsampling by way of after-market media players to experiment with sending the ARC deck higher sampling rates. (Mac users can achieve the same with Amarra or PureMusic for just two options). In Windows 7 users will want to deactivate ‘exclusive mode’ under systemsoundDAC8 Out 1|2. After installation of the driver, a small icon will appear in the same task bar where one usually safely removes USB sticks or external hard drives. Here one can select the desired sample rate.

A slitty-eyed glance through the top-side air vents confirms the Yanks’ foible for curves in the layout of their circuit boards. ARC finds 90° trace angles sonically and measurably inferior. "The advantages of curved circuit traces are very real. Right angles cause measurable impedance jumps, signal reflections and ultimately added jitter. Gentler directional transitions minimize jitter."