Lexicon Converter - Manual (Page 29)

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Using the 20/20 AD 20/20 AD User Guide
Operating the 20/20 AD
in the Digital Mode The 20/20 AD's Digital Input mode can be used to make use of the digital
compressor, or to noise shape the dither spectra before recording 20-bit source
material to a 16-bit recording device*.
In Digital Input Mode, format in = format out. No format conversion is
possible, and the front panel format indicator and selector are disabled.
This means that you must carefully consider the compatibility of your
source format and the requirements of any connected digital recording
device.
1. First, turn down your audio monitors. As the 20/20 AD will be connected in
the digital audio path, interconnects in the digital domain may disrupt any D/
As downstream.
2. Connect your digital audio source to the 20/20 AD rear panel AES/SYNC
input. The front panel PRES indicator should light.
3. Connect the 20/20 AD digital output to your recording device.
4. Press and hold down 1dB SCALE (ALT)and press the EXT SYNC button. The
20/20 AD will mute analog audio at the input, disable word clock on the BNC
connector, and lock onto the incoming AES signal. Once the 20/20 AD locks,
all four digital mode indicators will light.
Digital Input Mode
AES / WC:
EXT SYNC
WC AES
PRES LOCK
Once the 20/20 AD is configured for digital audio, the analog inputs are disabled.
In conformance with AES standards, only two channels of digital audio can be
processed through the digital input. All six digital outputs are active.
The left front panel meters show digital audio input. The right meters show 1dB
scale (if selected), or gain reduction when the compression function is selected.
To return to analog input operation, turn down your monitors and press EXT
SYNC while holding down the 1dB SCALE button. This will reinitialize the unit
with the analog inputs active. Recalibration of the converters will take approxi-
mately one minute.
Note that powering off will also return the unit to analog input mode, which is the
default state of the 20/20 AD. If you want to operate in the digital input mode, you
must reconfigure the unit each time the unit is powered on.
*This feature is standard as of Serial # 1215, and is available as an update for
earlier units.