Benchmark DAC1

USA, DAC1 digital-to-analog converter / headphone amp, the company should shake off its “just broadcast gear” reputation.

Features
   Priced at $795, the DAC1 is a half-rack, stereo 24-bit, 96 kHz DAC with two stereo headphone outputs. Like the companies high-end stereo multichannel A/Ds and D/As, the DAC1 uses Benchmark’s UltraLock™ digital circuitry which is said to eliminate jitter from the incoming digital signal.  (Jitter, a measurable artifact of digital signal timing errors, can audibly degrade performance of a digital audio playback). The converter plays back at any rate up to 24-bit, 96 kHz, and also detects pre-emphasis and enables de-emphasis at all of the sampling frequencies.
   Other features include high-current headphone amp (with two jacks) with enough juice to drive nearly any headphones at low distortion. The headphone volume is mounted on the front panel.
   Input jacks are AES/EBU, BNC (with included BNC-to-RCA adapter) and TOSLink inputs. Output jacks include balanced XLR and unbalanced RCA. A rear-mounted switch allows the output jack to be fixed or variable, thus you can use the DAC1 as a preamp for powered speakers. A pair of small potentiometers allow precise calibration of the fixed output levels.
   The front panel is simple in its layout. The three-position toggle switch selects between balanced AES/EBU, TOSLink or coax connections and the headphone volume provides for the gain. A status light bank indicates power on (blue LED), input error for improperly selected input (red LED) and non-PCM signal (red LED).
   Inside, the DAC1 is sturdily built with a high quality selection of parts including the toroidal power transformer. There is no power switch. Benchmark said it is designed for rack installations where power is centralized at one location.
   Although we did not measure this particular DAC, Benchmark sent along a set of measurements the engineers made

on an Audio Precision System Two. The claimed distortion of the DAC1 is .0005% at 0 dBFS input, and the jitter susceptibility is said to be unmeasurable.

In Use
   So what does all this jitter-free, low distortion mean in the real world? I put the DAC1 in my studio rig to find out.
  I connected the DAC1 in two configurations: With Monster Cable digital cable, I fed the AES/EBU input via the digital output from an Alesis MasterLink. I also fed the output of my Mac G3 workstation (using Peak 3.0 software and a Digigram VX222 I/O card) via a coaxial Monster digital cable to the coax input of the DAC1.
   I connected the outputs of the DAC1 and Alesis MasterLink to my Legacy high-current preamp balanced inputs so I could instantly compare the Benchmark and the MasterLink’s converters. I monitored using a set of NHT Pro A10 powered monitors as well as using a set of Grado SR-325 open headphones and a set of Sony MDR 7509 closed headphones for the headphone amp.
   For playback material, I played digital acoustic guitar recordings I made using the True System P2analog stereo mic preamp (also reviewed in this issue) and a pair of Audix SCX-25s and Neumann KM 184s. The recordings were made on the MasterLink at 24-bit, 88.2 kHz. With the both the MasterLink and DAC1 hooked up to my Legacy preamp, I could switch back and forth instantly to compare the audio.
   On the guitar recordings, you can tell how good the A/D is on the MasterLink by monitoring through the Benchmark. The audio was smooth, detailed and the increased string presence of 88.2 kHz vs. 44.1 kHz was definitely audible. The DAC1 revealed a subtle tightness to the bass and more focuses separation of the stereo soundstage than the MasterLink’s DAC. That does not mean that the MasterLink’s DAC is substandard; it is pretty good, but the test shows that quality, dedicated separates can offer audible, improved performance.
 

   As a playback DAC for my workstation, the Benchmark DAC1 was so revealing, quiet and smooth that it quickly became my reference monitor DAC: for headphone or speaker monitoring. With a converter of this quality, you can isolate the quality or lack of quality of the other components in the chain by getting reference playback that imparts no audible character of its own.
   By the way, for those who say they cannot hear the difference between the CD sample rate (44.1 kHz) and 88.2 kHz or 96 kHz sampling, try the DAC1. If you have any ears at all, the difference is audible.
   As for the headphone test, the DAC1 definitely had a more detailed, less smeared (though again subtle) than all my separates headphone amps including the MasterLink, Sony DAT deck, Fostex CD recorder and a Mackie mixer.
   Just a few quibbles. There is no power switch and no digital throughput for convenience feeding of digital signals to other devices in the chain. (although T adapter can be used with the BNC input to rig a ‘loopthrough’ – Ed.). Also, it would be nice to have HDCD decoding for those who playback their own HDCD encoded recordings or those who want to monitor prerecorded HDCDs. There are still a number of them out there.

Summary
   As I expected, The Benchmark DAC1 performed to the high pedigree the company has set for itself. Over the last seven years, getting products to test from Benchmark has been like pulling teeth; President Allen Burdick says the engineers are such perfectionists, they are reluctant to send out a product until they are satisfied it is “perfect.” Since I did get a DAC1, it must mean that spec-obsessiveness paid off.
  All in all, the DAC1 is an accurate, great sounding, versatile DAC for well under a grand. The proof is in the listening, so go out and listen to one.

   John Gatski is publisher of Pro Audio Review.