Usually, a Stereophile "Follow-Up" follows up (duh!) a full review of the component in question. This review, however, is intended to flesh out a cryptic comment made by Wes Phillips in April's "As We See It": "When Apple introduced its AirPort Express wireless multimedia link," Wes wrote, "it even included a digital port so that an audiophile—such as Stereophile's editor—could network his system, using the AE to feed his Mark Levinson No.30.6 outboard D/A converter. 'Sounds okay,' deadpans JA."
Back in the summer of 2009, USB-connected D/A processors that could operate at sample rates greater than 48kHz were rare. Ayre Acoustics had just released its groundbreaking QB-9, one of the first DACs to use Gordon Rankin's Streamlength code for Texas Instruments' TAS1020 USB 1.1 receiver chip. Streamlength allowed the chip to operate in the sonically beneficial asynchronous mode, where the PC sourcing the audio data is slaved to the DAC. But high-performance, USB-connected DACs like the Ayre were also relatively expensive back then, so in the January 2010 issue of Stereophile I reviewed a pair of soundcards from major computer manufacturer ASUS , the Xonar Essence ST and STX, which, at $200, offered a much more cost-effective means of playing hi-rez files on a PC.
With all the current fuss about getting audio data from a computer to a standalone D/A processor via S/PDIF, USB, FireWire, WiFi, or Ethernet (footnote 1), it has been overlooked that the oldest way to get audio from a PC is to use a high-performance soundcard plugged into the host machine's motherboard. I remember how excited I was when I installed a Sound Blaster Pro 16 board in the 486-based Dell running Windows 3.1 that I was using in the early Clinton era, plugged its analog output into my high-end rig, and played back 16-bit/44.1kHz files.
Thus spoke AudioQuest's Steve Silberman, VP of development, of their brand-new USB D/A converter, the DragonFly. "There are a lot of very good DACs out there," he continued. "There are even a lot of very good affordable DACs. But the problem is, people outside of audio don't want them: They don't want old-style components like that.
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.
These days, it seems you can't shake a stick without hitting a USB DAC, but Ayre's QB-9 ($2500) is something a little different. Ayre's marketing manager, Steve Silberman, was adamant: "The QB-9 isn't a computer peripheral. It makes computers real high-end music sources."
The speed with which audiophiles have adopted a computer of some sort as their primary source of recorded music might be thought breathtaking. But with the ubiquitous Apple iPod painlessly persuading people to get used to the idea of storing their music libraries on computer hard drives, the next logical step was to access those libraries in listening rooms as well as on the move. A few months back, I wrote a basic guide to the various strategies for getting the best sound from a computer: "Music Served: Extracting Music from your PC." Since then, Minnesota manufacturer Bel Canto Design has released a product that aims to simplify matters even further.
Erick Lichte's review of Benchmark's DAC2 HGC D/A converter in this issue gave me an ideal opportunity to spill some ink on the company's ADC1 USB A/D converter. The ADC1 is housed in the same small case as the DAC (one rack unit high, half the rack unit width), and is offered with a black front panel with rack ears, or a silver aluminum panel without ears, either for $1795.
Most of this column is dedicated to two hi-fi products for the massesnot from Lvov, via Vladimir Lamm, of Lamm Industries; or from Leningrad, via Victor Khomenko, of Balanced Audio Technologies; nor from any other Soviet-born audio hero. (Neither Vladimir nor Victor is on the list of "Name of Russia" contenders for greatest Russian of all time.) Nor from any consumer audio company, but from the world of professional audio. An Iron Curtain almost separates the two.
In his July 2003 "The Fifth Element" column, John Marks enthusiastically wrote about the Benchmark Media Systems DAC1 D/A processor and headphone amplifier. Comparing its sound playing CDs with that of a three-times-more-expensive Marantz SA-14 SACD player, he concluded that the DAC 1's "Red Book" performance was at least as good as that of the Marantz, being "slightly more articulate in the musical line, and slightly more detailed in spatial nuances, particularly the localization of individual images in space, and in soundstage depth."
In February 2009, I reviewed Bryston Ltd.'s first CD player, the $2695 BCD-1, and was very impressed by what I heard. The BDA-1 ($1995) is the Canadian company's first standalone DAC. It's slim, only 2.75" high, with the engraved company name, model number, and infrared sensor grouped at the extreme left of a front panel of polished aluminum. Farther to the right are two columns of four LEDs each that comprise the sample-rate indicator, which identifies the selected input's signal frequency and whether the BDA-1 has locked to it. Closer to the center is the Upsample control, which governs the conversion of the incoming digital signal synchronously to 192kHz or 176.4kHz. The Upsample LED turns green for 192kHz, red for 176.4kHz. Digital sources are selected by pressing one of eight pushbuttons just right of center: two TosLink, four S/PDIF (coaxial), one AES/EBU XLR, and one USB 1.1, the last accepting only signals with sample rates at or below 48kHz. An LED above each pushbutton lights green for an incoming PCM datastreams and red for other types, including multichannel Dolby Digital streams.
In 1989, Cambridge Audio, then run by Stan Curtiswho is still active in hi-fi introduced their DAC 1. At about the same time, within a few weeks of each other, Arcam introduced their Delta Black Box and Musical Fidelity their Digilog. I forget who was first among the three. Arcam, I think. But the DAC race was on, led by the British. (There was even a DAC called the Dacula.) US companies got into the DAC race, tooat higher prices, of course.
Sure, Stereophile gets letters to the editor. We also get some colorful responses for our "Manufacturers' Comments" section. (Vince Bruzzese and Roy Hall are literary standouts among their component-making peers.) And, as one of the magazine's Contributing Editors (Audio), I get lots of personal mail from readers seeking my advice. I thought I might share some of these letters with you, and my responses.