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Microphone Input:
The AUX 4 preamplifier position is supplied from the factory with a microphone preamplifier, Part No. 1620-PC, installed. Connection
is made via a standard XLR-type socket. The wiring convention is:
Pin 1 – Screen
Pin 2 – Hot +ve
Pin 3 – Cold -ve
The microphone to be used should be a low impedance type. If the Microphone is unbalanced, the Common and Shield pins in the cable
connector should be connected together.
Auxiliary Line Level Inputs:
Five sets of auxiliary line level inputs are available on the Model 1620LE, labelled AUX A, B, C, D and E. Connection on the rear panel
is through RCA-type phono jacks. These inputs may be accessed by any of the selector switches associated with the front panel input
level controls labelled AUX 1– AUX 4. Additionally, the inputs on the back panel labelled AUX 1 through AUX 3 may be used as line level-
inputs as supplied from the factory, with no preamplifier cards installed and the switches on the mother board bypassing the internal
preamplifier connectors: refer to switch location diagram on page 26.
