Benchmark Media Systems DAC1 USB

Benchmark Media's DAC1 has
been a long-standing staple in DAC conversations - this is the USB version.

If you look on Benchmark's
website you will read "The DAC1 USB has been replaced by the DAC1 HDR
which provides all of the functions of the DAC1 USB but adds remote control,
analog inputs, an extra digital input, and a motorized volume control. The
performance of the two units is identical.  

So, if you don't need some
of the 'pre-amp' comfort creatures of the HDR this is probably a great a way to
go.

Stereophile’s John
Atkinson wrote the following review in January of 2008

http://www.stereophile.com/digitalprocessors/108bench/index.html#IKUajO4yQwJoihjm.97

Over the last year plus I’ve
done some much needed system consolidation so this great DAC is no longer used.  The unit is in exceptional condition; I’ve
rated it a 7 simply due to age, and it comes with the original power cord, the
manual, and the box.  One note about the
box, this box may be from a non-USB version. 
I had a few of these DACs and when selling one of the non-USB units I
may have put it in the wrong box – I point this out as the box doesn’t indicate
the “USB version” on the label; I don’t know if it did, but I’m not sure so am
pointing this out up front.

Actual shipping costs and
PayPal fees will be the buyer’s responsibility. 
Please feel free to ask any questions.

Some details from Benchmark’s website:

[http://benchmarkmedia.com/products/benchmark-dac1-usb-digital-to-analog-converter]

The DAC1 USB (USB DAC) is a
reference-quality, 2-channel 192-kHz 24-bit digital-to-analog audio converter
featuring Benchmark's Advanced USB Audio™ technology, UltraLock™ clock system,
and HPA2™ headphone power amplifier.

The DAC1 USB has all of the features of
the DAC1 plus:

• USB Audio 1.1 interface (96 kHz, 24 bits)


• Programmable headphone gain - 2-settings  (0 dB and -10 dB)


• Programmable
  mute switch on left headphone jack

And some details about the DAC1 (again
from Benchmark Media Website)

[http://benchmarkmedia.com/products/benchmark-dac1-digital-to-analog-converter]

An Industry Standard

Benchmark's award-winning DAC1 has
become a standard in the finest recording studios and mastering rooms. 
Audio engineers rely of the accurate, uncolored, and precise sound of Benchmark
DAC1 converters.  The DAC1 is free from digital artifacts and its analog
sound eliminates the fatigue that is caused by many digital devices. 
Audiophiles have also discovered the smooth and detailed sound of the DAC1, and
it has become a centerpiece in may home listening rooms.

International Power Supply

The large internal power supply supports
all international voltages and has generous margins for over and under voltage
conditions. The power supply is sized to supply the demands of the HPA2™
headphone power amplifier when driving two sets of headphones.

Calibrated or Variable Output Levels

The front-panel gain control sets the
output level of the headphone jacks. It can also be used to control the output
level of the balanced XLR and unbalanced RCA analog outputs. A rear-panel
switch selects "Variable" or "Calibrated" output
levels.  In the "Calibrated" setting, the rear-panel outputs are
controlled by multi-turn calibration pots.

Direct Interface to Power Amplifiers

All Benchmark DAC1 and DAC2 converters
are designed to directly interface with power amplifiers and powered
monitors.  The XLR outputs are equipped with Benchmark's exclusive
low-impedance passive output attenuators.  These attenuators can be set in
10 dB steps to optimize the gain-staging between the DAC and the power
amplifier.  This important feature maximizes the signal to noise ratio of
the entire playback system.

Jitter-Immune UltraLock™

Digital interconnect cables,
electro-magnetic interference, and many other variables introduce jitter into
the digital audio. Jitter presents a major problem to most D-to-A converters.
Jitter is a type of clock error that, if not properly addressed, can cause the
D-to-A to misfire. The result of these misfires is a non-musical, digital distortion.

Many modern (and expensive) converters
suffer from severe jitter-induced distortion. Jitter is NOT a problem for the
DAC1, which achieves jitter immunity by utilizing Benchmark's proprietary
UltraLock™ clock-recovery system.

With the UltraLock™ clock-recovery
system, the digital-to-analog conversion-clock in the DAC1 is totally
isolated from the clock of the digital audio input. This clock-recovery
topology outperforms even the most well-designed two-stage PLL designs. Using
state-of-the-art Audio Precision testing equipment, no jitter-induced artifacts
can be detected with the DAC1. Any signal that can be decoded by the AES/EBU
receivers will be reproduced without the addition of any measurable jitter
artifacts. The bottom line is this: Benchmark converters will consistently and
faithfully deliver truthful audio with no jitter-induced artifacts, no matter
what variables are present.