Benchmark DAC1 Pre USB D/A headphone amplifier
They're two combination headphone preamplifiers and DACs: the Benchmark DAC1 Pre USB and the Grace Design m902 Reference. And I'm not supposed to tell you, tovarish, but Audio Advisor sells the Benchmark, and you can order factory-direct. B&H Photo and Video offers both the Benchmark and the Grace Design (not to be confused with Grace Digital).
Remember, just about any headphone amp can be pressed into service as a line stage. Just use an adapter to plug your interconnects into one of the headphone jacks. It works, if you don't mind an awkward adapter and interconnects dangling from the faceplate. Ray Samuels Audio has long offered some excellent headphone amps that you can conveniently use as line stages. So do Vincent Audio and Cayin Audio.
The Benchmark and Grace Design products include a versatile digital-to-analog converter. This is revolutionary, maybe subversive: DAC, headphone amp, and line stage, all in one box. Naturally, most of their dealers are pro-audio dealers pro as in proletarian.
I have Stereophile's mischievous Mr. Marks (not Marx) to thank for this month's columnand no, this is not a "shoot-out" in which one product is killed, like Alexander Hamilton or Alexander Pushkin, while the other beats it into the bushes like Aaron Burr. Both are winners that do more or less the same thing. They're almost identical in size (small), and close in price. But they sound very different. If one is right, the other must be wrong, and vice versa. Right, Chief?
Nyet. I can hear John Atkinson groan and John Marks cackle. I can also imagine readers who are considering both but can audition neither. Almost everyone who's bought the Benchmark DAC1 Pre or Grace Design m902 has done so via online mail order. Blind faith!
Auditioning hi-fi gear is more likely to lead to a bum buying decision than a good one. Read and make your mind up before you hear it. Most audiophiles do, anyway. (JA will cut this.) Why bother to audition just to confirm when you already know, from reading this rag, what you'll hear?
JA had a go at the Benchmark DAC1 USB D/A processor and headphone amplifier in the January and July 2008 issues. That product remains available for $1275. The DAC1 Pre retails for $1575 and is now quite the rage. Ken Kessler crowed about it in the August Hi-Fi News, as did Paul Miller when he tested it.
The DAC1 Pre has five digital inputs: three S/PDIF (RCA, 75 ohm, coax), one optical TosLink, one USB. Plus a single pair of unbalanced analog RCA inputs. There are unbalanced RCA and balanced XLR outputs. You can probably use your old CD player as a transport until it breaks, which eventually it will. The Benchmark's proprietary UltraLock should calm any jitters. (See JA's measurements.)
The Benchmark DAC1 Pre is minimalist except for its instruction manual, which is nearly 50 pages long. Among many other things, the manual tells you how to change the attenuation levels for the headphone gain and line-stage gain by way of internal jumpers. From the factory, the Benchmark DAC1 Pre comes preset with 20dB of line-stage attenuation, but I found I needed 10dB. This shaky-fingered sextuagenarian managed minus mishap.
Interfacing the DAC1 Pre's USB input with my Mac mini running OS X10.3.9 was a relative breeze. I opened Audio Midi Setup and chose the Benchmark as my default output. I also clicked on Audio Properties to choose 24-bits/96kHz. Then I opened iTunes.
The DAC1 Pre is said to bypass the operating system's sample-rate conversion (Windows Vista, XP, or 2000; or Max OS X) and to extend the word length to 24 bits. According to Benchmark, a 24-bit path is especially important for USB. A 16-bit path truncates bits. According to the Benchmark manual, "Our tests show that 24-bit output devices deliver a dramatic improvement in sound quality when playing 16-bit material."
Maybe you need those eight extra bits to let all 16 bits breathe, and 24 bits may offer more breathing space than 20. Credit Analog Devices for the AD1896 24-bit sample-rate converter and National Semiconductor for those LM4562 op-amps in the analog output stage. A product like this wouldn't have been possible a few years back, before op-amps got good. Real good.
Via a balanced XLR connection, I ran the Benchmark straight into Parasound Halo JC-1 mono power amps and a Cary 120S stereo power amp. I also tried a Conrad-Johnson LP66S stereo power amp, running unbalanced.
To get a subjective take on the Benchmark's DAC, I compared it with the Cary CDP1 CD player through the Benchmark's analog inputs. I also used the Cary CDP1 as a transport, feeding one of the DAC1 Pre's coaxial digital inputs via an Analysis Plus Digital Oval interconnect (see later). I strained to hear differences but decided I couldn't.
Take this as high praisethe Cary CDP1 is one of the finest CD players I've heard. If the Benchmark can elevate your present CD player (used as a transport) to the level of the Cary, maybe you should go for it and get a fine headphone amp plus line stage, too.
Internet radio from my Mac mini using iTunes was a revelation. The sound of a good Internet radio stream (such as those of KCSM or WCLV) was surprisingly good and very listenableplenty of air, ambience, and crisp, clean transients. More thickly orchestrated passages did sometimes congest, but considering the sound of most terrestrial FM radio broadcasts, I'm not complaining.
I also felt that the Ray Samuels Audio Emmeline The Predator headphone amp, which I reviewed in September 2008, is excellent for Internet radio via USB, and the Predator is a small fraction of the size of the Benchmarksay, 20 times smaller. No one would take the Benchmark (or the Grace) on the road with his or her laptop.
As for the Benchmark's overall sound, I thought it tipped slightly toward the lean side of neutral. It wasn't sterile or hard, by any means; perhaps what I heard was accuracy. In any event, don't look to the Benchmark to impart richness and warmth to your system.
The Benchmark could prove to be a revelation. If you buy the DAC1 Pre, as opposed to Benchmark's basic standard DAC without USB ($975), you leave your options open. Maybe you can ditch your present line-stage preamp and simplify your system.
You could use the DAC1 Pre in your office with your desktop or laptop, for a dramatic improvement in sound over your computer's built-in soundcard. And I do mean dramatic. You can drive a pair of powered speakers directly from the Benchmark. Or try a small power amp, maybe even a little single-ended tubed triode.
As for the analog output stage, it was fine, and showed that op-amps have become very respectable indeed. But get realdon't expect the Benchmark DAC1 Pre to trounce a really great dedicated line stage, such as the Parasound Halo JC2 or Conrad-Johnson CT5, both of which I had on hand for comparison. In terms of dynamic shadings, tonal color, and, of course, control flexibility, a great dedicated line-stage preamp is likely to win out. The wonder is that the Benchmark came so remarkably close.
As a headphone amp, the Benchmark DAC1 Pre really shoneeven with fussy, difficult-to-drive headphones like my reference AKG K-701s, or my affordable faves, the Audio-Technica ATH-AD700s. Again, the sound was crisp, clean, maybe a tad lean. Bass control was excellent.