Graham-Patten SoundPals, User Manual

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20 • ADC-20 SoundPals User's Guide
The figure below illustrates the ADC-20’s front panel:
ADC-20 ADC-20
AES OUT
+6V
-60
-20
-3
0
L R
LEVEL
EXT
REF
6 5
3 4 7 1
L R
2
GAIN
1) Left Analog Input Gain Trim — L GAIN sets the left
channel’s analog input level (the level that you want to
correspond to -20dB below digital clipping).
2) Right Analog Input Gain Trim —
R GAIN
sets the right
channel’s analog input level (the level that you want to
correspond to -20dB below digital clipping).
3) AES Unbalanced Output — provides AES unbalanced output
(BNC). Output is concurrent with the rear panel’s AES
balanced output (XLR) — both can be used simultaneously.
4) AES Reference LED — the EXT REF LED lights when the
sampling frequency is locked to the externally supplied AES
reference signal. The LED is an indication only, not an alarm.
5) Level Indicator LEDs — provides level indication for each
input (calibrated in dB). When properly adjusted, the
following levels are indicated:
• −−
60 dB: signal present
• −−
20 dB: normal digital reference level
• −−
3 dB: approaching clipping
•
0 dB: A/D converter is clipping
6) Power Connector — accepts the power jack from the 6 VDC
power supply. Refer to Appendix B for more information
regarding external power.
7) Power LED — the large green LED below the power jack lights
when power is applied.