Chapter
1
A D 2 4 0 2 - 9 6 - O P E R A T I N G M A N U A L
System Overview
A brief overview of the AD2402-96
The AD2402-96 is a 2-channel, portable version of the Benchmark 4-channel AD2404-96 and 8-
channel AD2408-96 24-bit 96-kHz converters. The Benchmark AD2404 was designed to
provide the best possible sonic performance. The AD2402-96 faithfully replicates this
performance in a portable package.
The circuit design, components, construction
techniques, and sonic performance of the AD2402-96 are identical to those of the AD2404.
Sample Rate
The AD2402-96 operates at fixed sample rates of 44.1 48, 88.2 and 96-kHz
. In addition, a
“Variable” or “Varispeed” mode allows the converter to operate at any sample rate between
24-
kHz and 100-kHz
.
Word Length
Output word lengths
can be set at
24, 20, or 16-bits
. The 20 and 16-bit word lengths are re-
dithered from 24-bits using either the
Benchmark NN™ or NS™ word length reduction
systems
. The NN™ and NS™ systems are optimized for the selected sample rate, and for the
number of bits being removed. NN3 and NS3 can achieve near 20-bit performance on a 16-bit
recorder. The NN1, NN2, NS1, NS2, settings are optimized for noisier recording environments.
TPDF (white noise) dither is also a selectable output choice.
A unique feature of the AD2402-
96 allows simultaneous 24 and 16-bit outputs.
Digital Audio Reference
A digital audio input jack allows the AD2402-96 to phase-lock to an external AES or SPDIF
digital audio reference.
Most 2-channel applications will not require an external reference
and many users will never need to use the external reference input.
However, the external
reference is provided to allow phase-accurate multi-track recording with two or more AD2402-96
5
