Digital Processor Reviews

In equipment reports, I use the phrase forward momentum to refer to something a little deeper and more encompassing than what's meant by that well-worn Brit-fi expression pace, rhythm, and timing (PRaT). Pace refers to the speed at which a piece of music is being played, and the accurate reproduction of that speed requires audio sources with good dynamic pitch stability. (Digital folk always lord it over LP clingers for digital's superior pitch stability.)

It's been going on for a while now: Despite support for multichannel in audio/video receivers and A/V processors priced from as little as $200 to $30,000, there are still very few offerings that cater to the music listener. They may offer stereo-only streaming features through their USB or Ethernet inputs, but these inputs don't see your multichannel files. To handle such files, they would require you to add a music server with HDMI output. However, I know of no turnkey music servers that will output multichannel audio via HDMI.

Fifteen years? Has it really been 15 years since I reviewed what was then the flagship D/A processor from English company Chord Electronics? In the July 2002 issue, here's how I summed up my review of the Chord DAC64: "While the Chord Electronics DAC64 is undoubtedly expensive, it is eye-poppingly gorgeous. . . . many listeners should find its silky-smooth highs seductive, as well as its slightly larger-than-life lows." How times and prices change—the "undoubtedly expensive" DAC64 cost only $3040! I did make a couple of criticisms of the DAC64 in my review, but according to Wes Phillips, in his August 2007 review of Chord's revised DAC64, "the Choral Blu [CD transport] and Choral DAC64 are, together, the CD player we music lovers have long prayed for"—even if, five years after my own review, the DAC64's price had risen to $5000.

As I mentioned in my review eight years ago of Meridian Audio's 808.2 Signature Reference CD player, I have long been impressed by the British company's components—in fact, ever since the early 1980s, when I purchased a Meridian 101 preamplifier, followed by my very positive experiences with Meridian's MCD Pro and 208 CD players, 518 digital audio processor, D600 and DSP8000 digital active loudspeakers, and, most recently, the Prime and Explorer D/A headphone amplifiers.

Right now, I swear, Schiit Audio's Mike Moffat and Jason Stoddard are sitting there in California, smugly smirking at me and John Atkinson. While JA was struggling to properly measure Schiit's Ragnarok (Fate of the Gods) integrated amplifier for my review in the May 2016 issue, I sent Moffat an e-mail: "Are you smiling?"

"Yup," he replied. He'd known in advance that the Ragnarok wouldn't look good on standard tests. But he hadn't warned us: The Ragnarok's output-stage bias program responds to music sources, not signal generators.

It has been 20 years since I first became aware of the British company Data Conversion Systems, which manufactures audio products under the dCS brand. Rather than use off-the-shelf conversion chips, the groundbreaking dCS Elgar D/A converter, which I reviewed in our July 1997 issue, featured a then-unique D/A design that they called a Ring DAC. This featured a five-bit, unitary-weighted, discrete DAC running at 64 times the incoming data's sample rate—2.822MHz for 44.1kHz-based data, 3.07MHz for 48kHz-sampled data and its multiples—with upsampling and digital filtering and processing implemented in Field Programmable Gate Arrays (FPGAs). Oversampling to a very high sample rate allows the word length to be reduced without losing resolution, and use of a low-bit multi-bit DAC makes for very high accuracy in the analog voltage levels that describe the signal. (If this seems like voodoo, for a given signal bandwidth, bit depth and sample rate are related. To oversimplify, double the rate, and you can reduce the bit depth by one bit while preserving the overall resolution.)

"They're so damn hard to tell apart!"

So exclaimed my longtime pal and fellow audiophile Bruce Rowley when I revealed to him that T+A Elektroakustik's new DAC 8 DSD digital-to-analog converter ($3995) had arrived for review, just after I'd finished writing up the Ayre Acoustics Codex DAC–headphone amp ($1795). Bruce had recently compared his own brand-new Codex with a DAC he'd owned for a couple years, both costing about the same but built to very different designs. He was surprised that, after carefully matching levels and working to eliminate any other variables, they sounded more alike than not, and only slightly different even after hours of listening. Technically, these were two very different animals.