Digital Processor Reviews

Of all the products I've reviewed or auditioned, a select few jump out as "best buy" recommendations. Almost universally, such products are liked by a wide range of audiophiles, and seem to match well sonically to many systems. Moreover, these products all have outstanding value; they offer a higher level of musical performance than you'd expect from the price.

The night before I started to write this review, PBS began a five-part series on computers called "The Machine that Changed the World." The first episode described the development of the ENIAC (Electronic Numerical Integrator and Accumulator), the first electronic computer. The ENIAC used 18,000 vacuum tubes, had over 500,000 solder joints, required a room 30' by 50', had to be physically reprogrammed with patch cords to perform different tasks, and packed less computing power than today's $4.99 pocket calculator.

Like all men, I learned at an early age to resist the allure of a pretty face.

Okay—I learned that I should try to resist the allure of a pretty face.

Okay, I confess: I have never been able to resist the allure of a pretty face. Which is why, when I first clapped eyes on the Mojo D/A headphone amplifier from English company Chord Electronics, at an event hosted by Manhattan retailer Stereo Exchange, I had to borrow a sample for review.

The EAD DSP-1000 III is housed in a 2.5" high, U-shaped chassis with a brushed-aluminum front panel. The cover is made of solid, 1/10"-thick steel with a nice "powder" finish, giving the unit an expensive feel. A pushbutton standby switch sitting below a green LED indicator sits at the panel's left. Even when set to Off, power is maintained for the decoder's circuits, but the digital inputs and analog outputs are muted. To the right, three pushbuttons allow selection of one of the three digital input sources (TosLink, 750 ohm coaxial, or glass optical interface). Like the EAD DSP-7000 unit reviewed by J. Gordon Holt and Steven Stone (Vol.18 Nos.1 & 5), the DSP-1000 accepts any of the three sampling rates: 32kHz, 44.1kHz, or 48kHz. Toward panel center is a lock light that illuminates when a digital data link is established. HDCD decoding occurs automatically whenever an HDCD disc is played, causing the front-panel HDCD indicator to light. No remote is available for this decoder.

UpTone Audio's USB Regen is a powered, single-port USB 2.0 hub that takes the USB signal from your computer, regenerates (ie, reclocks) the data, provides cleaned-up 5V power from a built-in, ultra–low-noise regulator, and sends an impedance-matched signal to your DAC. The Regen is designed to sit as close to your DAC as possible; UpTone supplies a male/male USB A/B adapter—a solid, double-ended plug, which they recommend over the 6"-long male/male USB A/B cable they also provide.

I got an early start on computer audio. At the end of the last century I was using WinAmp with first a CardDeluxe PCI soundcard, then a similar card from RME, to play files on a Windows PC. After I became a MacPerson, I used FireWire audio interfaces from pro-audio company Metric Halo and an inexpensive USB-connected ADC/DAC from M-Audio. But it was with the USB version of Benchmark's DAC 1 that the computer began taking over from physical discs for my music listening. At first I used iTunes au naturel, but as I acquired more high-resolution files, I began using Pure Music to handle all the tedious audio housekeeping, assigning as a dedicated music server a G4 Mac mini I'd bought in 2006.

The availability of the Pacific Microsonics High Definition Compatible Digital (HDCD®) PMD100 decoder chip, manufactured by San Jose's VLSI Technology, has brought about a minor revolution in Compact Disc playback. It brings sonic improvements in imaging, soundstaging, and resolution of detail. In the past six months, Stereophile has published a number of reports on the HDCD decoder's operation, what HDCD recordings are available, and the improvements brought by the HDCD chip to specific digital audio processors (footnote 1). High-end manufacturers are incorporating the $40 HDCD chip in their newest decoders, including the $4695 Sonic Frontiers SFD-2 Mk.II D/A processor, the $15,950 Mark Levinson No.30.5, and the $8195 Spectral SDR-2000 Professional HDCD D/A Processor (reviewed in Vol.18 No.5).