ADC16 Instruction Manual
– Rev A
Page 3
Overview
The ADC16 is a reference-quality, 16-channel,
192-kHz, 24-bit, analog-to-digital audio
converter.
The ADC16 utilizes Benchmark's
UltraLockDDS™ clock system with multi-
function clock input and word clock output.
UltraLockDDS™ is a proprietary clock-sync
system that is immune to jitter.
UltraLockDDS™ is phase-accurate, even
across multiple ADC16 units.
The ADC16 has a wide variety of interfaces,
including AES/EBU, coaxial, ADAT, Toslink,
and more via an optional interface card. The
optical output supports AES or ADAT formats
at resolutions up to 192/24. In ADAT mode,
high sample rates are supported using
S/MUX
2
and S/MUX
4
. The optional interface
card will enable direct connectivity to a
computer and other devices.
The signal-level meters on the ADC16 are
dual-range, 9-segment LEDs. The meters can
easily be switched to display a range of 48 dB
or 20 dB. The meters also have a peak-hold
function. The meters are single-sample
accurate for precise digital signal metering.
The ADC16 is designed for maximum
transparency. The ADC16 is well suited for
the most demanding applications in recording
and film studios. The internal power supply
supports all international voltages and has
generous margins for over and under voltage
conditions.
The ADC16 achieves outstanding performance
over a wide range of input levels. Each
channel has a 10-turn gain calibration
trimmer with a gain range of 23 dB. The gain
calibration controls may be used to calibrate
the ADC16 to precise studio reference levels.
The ADC16 has a BNC Word Clock output that
follows the sample rate indicated on the
front-panel display. Word Clock output is
active in all modes of operation.
A multi-format clock-input automatically
recognizes AES/EBU, SPDIF, Word Clock, or
Super Clock signals. This clock input is used
to synchronize the digital outputs. If desired,
the digital outputs may be clocked to the
ADC16's high-precision internal clock. The
ADC16 will automatically revert to the internal
clock source when the external clock is lost.
The ADC16 has four clock modes: 'DAW'
(optional interface card), 'AES' (DB-25
AES/EBU input), 'WC' (BNC), and 'INT'
(internal). All modes support sample rates
between 28 kHz and 200 kHz.
The 'DAW', 'AES', and 'WC' modes allow the
ADC16 to lock to an external clock reference.
In these modes, the ADC16 will follow
changes in sample rate. In 'WC' mode, the
ADC16 will also follow changes in the type of
reference signal (AES, SPDIF, word clock, or
super clock).
When the 'INT' mode is chosen, the ADC16 is
acting as clock master, operating at the
selected sample rate. In the 'INT' mode, any
signal at the clock-reference input will be
ignored. If 'INT' mode is used, all devices
connected to the ADC16 digital outputs will
need to be configured to lock to the ADC16.
Also, if the 'INT' mode is used, all other digital
sources (A/D converters, etc) connected to
the recording system must be synced to the
ADC16's clock. The 'WC' output and any of
the digital audio outputs on the back of the
ADC16 may be used as clock references to
feed connected devices.
The Benchmark UltraLockDDS™ clock-system
is highly immune to jitter. When synced to
the DAW, AES/EBU, WC, and super clock
interfaces, the A/D conversion-clock is
optimally conditioned using a technology
called Direct Digital Synthesis (DDS). The
UltraLockDDS™ system utilizes a
temperature-compensated crystal oscillator to
achieve an accurate center frequency
(important when the ADC16 is operating as a
master clock). The DDS system operates at
