Digital Processor Reviews

Stereophile normally doesn't review audio systems. We review individual components. We've made an exception for the Bel Canto Black system because it deserves to be evaluated as such. It consists of three dense, almost identically sized cases of black-anodized aluminum. One, the ASC1 Asynchronous Stream Controller, is what in a conventional system would be called a "preamplifier." The other two, a pair of MPS1 Mono PowerStreams, would in a conventional system be called "monoblock power amplifiers."

Aurender was a name new to me when I encountered the company at the 2015 Consumer Electronics Show, where they displayed a range of music servers designed in California and manufactured in South Korea. But what caught my attention in Aurender's suite was their Flow portable D/A headphone amplifier ($1295). This handsome, battery-powered device, housed in a machined aluminum case about twice the size of a pack of playing cards, offers optical S/PDIF and USB 2.0/3.0 input ports and a single ¼" stereo headphone jack. Two features distinguish the Flow from the pack: Its USB input can be used with iOS (iPhone/iPad) and Android smartphone sources, and it can accept an mSATA drive (not included in price) of up to 1TB capacity for internal storage of audio files. Visually, the Flow's distinguishing feature is its round LCD display, which stands proud of the faceplate; the bezel encircling the display acts as a velocity-sensitive volume control operating in 0.5dB steps.

During my reviews of digital processors in the past year or so, I've made comparisons with the Wadia 2000 Digital Decoding Computer first reviewed by Arnis Balgalvis in Vol.13 No.1. I've felt that, as good as the 2000 is, other processors—many costing less than the 2000's $8500 price tag—are now superior.

However, a visiting Wadia representative looked inside our sample and used the word "ancient" to describe its circuitry in relation to current production. In addition, I was never able to audition the 2000 with a glass fiber-optical interface, standard equipment on Wadia's transports. Similarly, the $2000 Wadia X-32 had undergone a minor circuit revision, including the inclusion of the glass optical input. Consequently, a follow-up of these two excellent processors seemed in order.

A decade or two ago, I stumbled on a surprising demo room at an audio show. I don't recall most of the equipment, but I do remember a pair of Paradigm Studio 20 speakers at one end, their crossover entrails dangling free, connected to the rest of the system by a multiplicity of wires. At the other end, among the usual electronics, was a PC whose screen was a crazy quilt of graphs and menus that constantly twinkled in response to the ministrations of DEQX's Kim Ryrie. He seemed totally absorbed, but looked up and proudly offered to show me what he was doing. When I told him that I was familiar with the Paradigms, he played some music that sounded just fine. Then he clicked his mouse. The sound was transformed from the familiar to the fabulous. I was dumbfounded. "What have you done?"

There may have been a time when vacuum tubes and microprocessors seemed strange bedfellows. But nowadays—given the countless digital processors with tubed output stages, and an even greater number of tubed amps and preamps whose insides are crawling with the latest solid-state devices—we're more or less used to the idea. Here as elsewhere, hybrids are no big deal.

A reader recently asked if I preferred listening to loudspeakers or to headphones. There is no easy answer: Although I do most of my music listening through speakers, about 10% of that listening, for various reasons, takes place in the privacy of my headphones. I have also found that, since I purchased the Audeze LCD-X headphones following my review of them last March, I now tend to watch movies on my MacBook Pro, with the soundtrack reproduced by these headphones plugged into an AudioQuest DragonFly or whatever D/A headphone amplifier has been passing through my test lab. So when Meridian's PR person, Sue Toscano, asked me last Christmas if I'd be interested in reviewing the English company's new Prime D/A headphone amplifier ($2000) with its optional Prime Power Supply ($1295), it took me less than a New York minute to say "Yes."

Professional digital audio is like gravity to consumer audio's antigravity: pro gear draws music into digital files, and consumer audio releases those same notes back out again.

It's not surprising, then, that many audiophile digital-to-analog converters come to us from the pro-audio industry, which has a hierarchy similar to the consumer side: value-oriented products all the way up to ultimate-performance brands. Examples of pro-audio companies that also offer audiophile DACs for consumers abound: Benchmark, CEntrance, Grace Design, Korg, Mytek, and Nagra, to name a few.