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Sunday, December 14, 2008

D/A Converters — Benchmark DAC1 PRE


Welcome!
  Welcome to the first installment of the everything audio network (EAN). As an audio junkie for as long as I can remember and having being involved in reviewing audio products since the early 1990s, I am excited about my new audio blog page. The mission is to offer insight and to conduct product tests for those who reside clearly in the high-quality audio niche. Whether its audiophile, multi-channel home theater or serious home recording, I will endeavor to keep you up to date on the good stuff. Since most enthusiasts seek out audio product info on the Internet, this web-based, delivery medium makes it easy to keep readers updated on trends and the latest products. No waiting for the mailman.
Enjoy the EAN!

Digital audio converters
  In this inaugural installment, I take an in-depth, look-and-listen to the Benchmark Media DAC1 Pre digital audio converter with newly available analog input/output. Unless you are using a turntable, tuner or tape machine (we still love those, right?), everything you use for playback these days contains a digital audio converter (DAC). Most internal PCM audio DAC chips are 24-bit/192 kHz sample rate, even if they don’t actually deliver that resolution.
  Integrated DACs in DVD, universal players, CD players, satellite receivers and computers are pretty good sounding, but they typically do not deliver the highest quality audio conversion in comparison to separate DACs, whose designers embody them with better parts, and, of course, higher prices.
  I have sampled numerous DACs over the last 10 years and have found that that the really well-designed units offer audible improvements in transient, response, imaging and detail over the built-in DACs at any of the sampling frequencies — 44.1 kHz through 192 kHz. Many casual listeners say they can’t hear the difference, but trained listeners and serious audiophiles say they can discern the subtle improvements delivered by separates, and I agree. Really good-sounding, built-to-last separate DACs vary in cost from about a $1,000 to northward of $10,000.
  Linking audio converters to the new crop of playback machines and computers is now a transitional issue. For years, DACs were connected to players either by TOSLink optical, SPDIF RCA jacks or AES /EBU balanced XLR output. With Blu-ray players now equipped with HDMI outputs as the high-resolution digital output and computers outputting digital audio on FireWire and USB ports, converters companies are looking at these second generation conduits to stay future proof. There are already a number of FireWire and USB DAC interfaces on the pro and semi-pro side, but I have not yet seen any separate HDMI input audio DACs.
  Another key issue for DAC manufacturers is the music industry’s obsession with copy protection, which means that many digital players downsample the digital audio to lower-quality sampling rates in order to supposedly thwart bit-for-bit cloning and potential proliferation of counterfeit copies. This downsampling mean separate converters don’t receive the highest quality signal possible. DVD-Audio players, for example, will not output digital audio from commercial DVD-As at the 192 kHz rate (automatically downsampled to 48 kHz), and many players will not output even at the standard high-res rate of 96 kHz. This limitation often frustrates the converter manufacturer, which is trying to give the customer the highest quality audio playback option.

  

"In this and in future forums, converters will be an integral — and ongoing — part of my discourse on playback product testing."


EAN Review
Benchmark DAC1 PRE
  Digital converters are a crucial link in the audiophile listening world, and the very good ones reveal subtle detail and sonic realism from recordings that make the prerecorded playback experience much closer to the real thing.
  Benchmark Media Systems, a company that got its start in the professional audio world, has been doing very well in the audiophile world with the 2002 introduction of the DAC1. With subsequent roll-outs of the DAC1 USB and DAC1 PRE tested here (plus excellent recording A/Ds), the company further strengthens its made-in-USA offerings to the high-end listening community.
  According to Benchmark’s Director of Sales Rory Rall, many of his customers had been asking for an all-analog path to complement the D/A section of the DAC1 — in order to take advantage of its excellent analog path. Hence, the DAC1 PRE.

The details
  The Benchmark DAC1 PRE, priced at $1,595 retail, adds analog input selection (RCA unbalanced only) that bypasses the digital converter to maintain an all-analog signal path through the headphone jack and line outputs. Like its other siblings (the standard AES/EBU,SPDIF, TOSLink input DAC1 and the DAC1 USB), the DAC1 PRE contains Benchmark's, ultra-low jitter and low-distortion converter that locks in all sampling frequencies 192 kHz and lower to 110 kHz. These converters have proven to be among the best in terms of sonic transparency — especially for the money.
  Benchmark shipped me a shiny, brand spanking new, silver-and-black DAC1 Pre unit. It resembles the standard DAC1 and the DAC1 USB on the front panel, except for a new knob control for rear-panel input selection. The rotary selector knob positions are: 1-TOSlink input, 2- SPDIF input, 3-SPDIF input, 4-SPDIF input, USB input, and the analog RCA stereo inputs. Unlike the its siblings, the DAC1 PRE does not have an XLR digital input.
  The front panel contains the two headphone jacks and a stepped-volume control. The headphone amp section is based on Benchmark's HPA-2 standalone headphone amp, which is one of the best available. Around back are the input and output connections, including the USB port for computers digital outputs, TOSLink SPDIF and three RCA SPDIF jacks. The RCA unbalanced analog input jacks, a pair of XLR balanced outputs and a pair of unbalanced RCA outputs round out the output section. A rear switch enables line-output to be fixed or controlled by the volume knob. An extra click of the switch mutes the analog line output.
  Internally, like the latest DAC1 USB and the standard DAC1, this latest Benchmark has improved line and headphone gain stages to make it easier to drive high capacitance loads with out any loss of sonic transparency.

The audition
  I sampled the DAC1 PRE through several different components outputs including an Apple MacBook Pro, Esoteric DV-50 universal player (SACD, DVD-A, CD and DVD-V) and the high-resolution capable TASCAM HD-P2 FLASH recorder. The playback chain included a Legacy/Coda preamp, Legacy Focus 20/20 speakers, Alpha Core speaker cables/interconnects and my favorite headphones, the AKG K701. Other converters on hand included a Bel Canto Dac-2, Mytek 24-96 and a Parasound 20-bit DAC — an oldie-but-goodie from the 1990s. Of course, I also compared the onboard DACs contained in the computer, Esoteric and high-resolution capable TASCAM players as well
  On prerecorded software recorded at high resolution sample rates, I selected AXI label’s Laurence JuberGuitar Noir album from, which I had downloaded from the label's ITRAX high-resolution download site. The 24 bit/-96 kHz stereo download was subsequently burned to DVD-Video via Roxio Toast. The tracks were played back through the Esoteric DV-50 universal player in stereo 24-bit/96 kHz. The DV-50’s SPDIF output was connected to the DAC1 Pre. The Esoteric will output 96 kHz sampling via the digital port as long as there is no copy protect proviso in the audio.
  The Laurence Juber disc is a great sounding, PCM-encoded jazz guitar recording, with a lot of transient and ambiance cues that are more detailed at the higher resolution sampling rates. I have used this album as a test recording for many players and DACs.
  Listening through the AKGs via the DAC1 PRE's headphone jacks, the audio playback was incredible. Guitar playing revealed layers of real-sounding subtleties of the string vibration, and the percussion sounded natural, yet dimensional. Almost like being in the studio
  The Mytek converter was good, but the detail in the treble region was more revealing on the Benchmark. To me it was ever so slightly more open and smoother than my original DAC1. And through the headphone amp using the AKG 701s, you can really hear those intricate subtleties Juber’s fingerstyle playing. Wow!
  I also played back some of my own acoustic and jazz guitar recordings that were recorded at 192-kHz sampling. As previously mentioned, the DAC1 Pre resamples all audio sampled to as high as 192 kHz to the 110 kHz sampling. So 192 is no problem. Recordings of my Martin D-35 and custom Martin OO-28, recorded through Audix condensers and a True microphone preamp, were exquisite. In particular, my stereo recording of the Gibson L-5 jazz guitar through a Fender Deluxe Reverb amp was warm, yet detailed.
 
"This converter just relays what the original recording chain allowed to be recorded — without a hint of PCM harshness."

  How about the new feature; the analog input/output stage. One at a time, I connected various sources (Esoteric, original Benchmark DAC1, Mytek 24-96, turntable/preamp) to the DAC1 PRE’s RCA input jacks. The DAC1 PRE’s output was then linked to a Pass Labs X350.5 amp via six ft. Alpha Core solid silver RCA cables, which powered the big Legacys. Compared to my reference Coda preamp, it was pretty close — nearly a toss up. The Coda is very neutral with a well-defined open sound stage and so is the Benchmark — though perhaps not quite as big image.

The verdict
  Since it has only one set of analog inputs, the DAC1 PRE cannot be considered a full-featured preamp. But if you use it as a DAC for your various digital components and you run your turntable preamp, analog tuner, or tape machine via the analog, you have a great little playback preamp for digital or analog. And I can’t say enough about the headphone playback. It may be one of the best headphone amps at any price.
  Overall, some may consider the $1,595 price point a little high for a stereo DAC and one set of analog inputs, but in my opinion, the sound quality makes the price complaint moot. My only niggle about the Benchmark is its lack of sample rate and word length indicators. It would be nice to see what rate the audio is actually being output from the source.

FLASH Points
Benchmark DAC1 PRE
Revealing Sound
Made in USA
Addition of Analog, USB Inputs
Killer Headphone Amp
Benchmark Media Systems located in Syracuse, New York, Access their web site at www.benchmarkmedia.com



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