Instruction Manual for DAC2 HGC and DAC2 L with 2.X Firmware Page 5
Introduction
Applications
The DAC2 is a professional reference-grade
audio digital to analog converter with
Benchmark's HPA2™headphone amplifier. It
supports 24-bit D/A conversion of PCM at
sample rates up to 192 kHz. It also supports
direct conversion of 1-bit DSD at a 2.8224
MHz sample rate. It is designed to be very
transparent and this makes it well-suited for
critical monitoring in studio control rooms and
mastering rooms.
The DAC2 is also well-suited for high-end hi-
fi environments. It includes a generous
collection of inputs and outputs and can serve
as the central component in any stereo hi-fi
system. It provides D/A conversion, source
selection, volume control, and headphone
amplification. A remote control, 12V trigger,
and home theater bypass function provide the
features needed in a home environment.
The DAC2 is designed to directly drive a wide
variety of power amplifiers and powered
monitors. The balanced outputs include low-
impedance passive pads that can be adjusted
to optimize the interface between the DAC2
and the power amplifier. This optimization can
provide substantial improvements in the
system-level SNR and THD+N performance.
DAC1 Heritage
The DAC2 builds upon Benchmark’s highly
successful DAC1 product family. The DAC2
maintains the familiar DAC1 form factor, but
adds more features, and more I/O while
delivering higher performance. Every DAC1
subsystem has been redesigned, upgraded, or
replaced in order to achieve the highest
possible transparency.
System Overview
The DAC2 adds these features that are not
found on the DAC1:
•Asynchronous 192kHz USB Audio 2.0
•32-bit D/A conversion system
•Word Length Display
•Sample Rate Display
•Polarity Control
•Direct DSD D/A Conversion
•-20 dB DIM
•Bi-Directional 12V Trigger
•Power Switch with Auto-On Function
•Home Theater Bypass
•Digital Pass-Through
•High-Headroom DSP
•Dual-Domain Hybrid Gain Control
•Additional I/O
Lower Noise than the DAC1
The conversion system in the DAC2 is about
10 dB quieter than the system in the very
quiet DAC1. To achieve this improvement, we
selected the Sabre ES9018 8-channel 32-bit
converter and externally summed two groups
of four channels using two low-noise analog
summing amplifiers of our own design. This
4:1 summing reduces the noise of the
ES9018 by about 6 dB. The net result is 13.5
dB quieter than the converter in the DAC1.
We have chosen to use 3.5 dB of this
improvement to provide headroom above 0
dBFS so that intersample overs will never clip
or overload the conversion system or the
digital processing. This reduces the net
improvement to 10 dB. Low-level musical
details are faithfully reproduced over a
breathtakingly quiet noise floor, and
intersample peaks are faithfully reproduced
without clipping.
No Clipping of Intersample Peaks
The DAC2 is one of very few D/A converters
that can accurately reproduce intersample
peaks without clipping. Intersample overs
commonly occur many times per second in
44.1 kHz and 48 kHz recordings. Additional
overs are added whenever lossy compression
systems (such as MP3) are applied. Most
converters (including the DAC1) produce
bursts of distortion at every occurrence. In
contrast, the DAC2 cleanly reproduces all
intersample peaks.
