Digital Processor Reviews

Those of us who groan at the appearance of every new five-figure digital source component in a massively oversized chassis—and who groan in greater torment when the offending manufacturer says his customer base insists on products that are styled and built and priced that way—can take heart: The appearance of such sanely sized and affordable products as the Halide Design DAC HD ($495) and the AudioQuest DragonFly ($249) would suggest that the market has a mind of its own.

Late last year came an epic audiophile moment: I slapped a final length of tape on the box of the awesome-sounding MSB Diamond DAC (Stereophile, October 2012), in final preparation for its trek to John Atkinson's testing lab, in Brooklyn. Next up was the Bifrost DAC from Schiit Audio. I popped it into my system, where, moments before, the MSB had held court.

From $43,325 to $449. Yowseh!!—the MSB costs almost 100 times as much as the Schiit! Was this even fair?

For the audiophile modernist, a DAC with volume control is the straightest path between the music server or network stream and your amp and speakers. If you've fully embraced networked audio, there's no need for fussy preamps with their analog inputs, analog volume controls, and [gasp!] phono stages. Find a digital source, a DAC with volume, and go.

No history of the computer-audio marketplace could be complete without some mention of High Resolution Technologies, the California company whose Music Streamer was, in 2009, the first perfectionist-quality USB digital-to-analog converter to sell for as little as $99. One could argue that HRT's entire business model has contributed to shaping our attitudes toward the hobby: Because digital-audio technology continues to evolve at such a rapid pace, HRT has introduced a succession of newer and ever more effective Music Streamers, occasionally to the obsolescence of their predecessors; yet because those products have all been so affordable—remarkably and laudably so, given their thoroughly American provenance—we tend not to mind.

You know what's fascinating? As digital audio technology matures, DAC design is not converging on a single most popular or overall best approach. Multiple design paths continue to thrive, new ones are still appearing, and each variation on the DAC theme has its adherents and side trails: bitstream, non-oversampling, upsampling, various filters, DSD playback options, and on and on.

As I wrote in my review of the Bricasti M1 D/A processor in February 2012, it seemed a good idea in the late 1980s: upgrade the performance of your CD player by feeding its digital output to an outboard digital/analog processor. British manufacturer Arcam, one of the first companies to see the opportunities in this strategy, introduced their Black Box in 1988. When I reviewed the Black Box in February 1989, I found that its low-level linearity was among the best I had measured at that time for a product featuring the 16-bit Philips TDA1541 DAC chip set. However, that linearity still wasn't very good in absolute terms. Back then, it required heroic and expensive engineering to obtain D/A performance that did justice to the 16-bit CD. These days, however, the semiconductor foundries produce a plethora of relatively inexpensive D/A processor chips that both handle 16-bit data with ease and wrest full resolution from 24-bit data.

Since its founding in 1993, Colorado-based Ayre Acoustics has made its name with amplifiers and preamplifiers based on truly balanced, solid-state circuitry that didn't use the ubiquitous panacea of loop negative feedback to produce linear behavior. Their first digital product was the D-1x DVD player, reviewed for Stereophile by Paul Bolin in February 2003, which offered unusually good video performance. The D-1x was followed by the C-5xe and DX-5 universal players, respectively reviewed by Wes Phillips (July 2005) and Michael Fremer (December 2010). But the most intriguing digital product to come from Ayre was the QB-9 digital processor. Reviewed by WP in October 2009, the QB-9 has just one input, USB, and uses Gordon Rankin's proprietary Streamlength code to give asynchronous operation, which in theory offers the best jitter suppression. "The QB-9 isn't a computer peripheral," said Ayre's marketing manager at that time, Steve Silberman. "It makes computers real high-end music sources"—a statement with which WP agreed.