Audio Developments AD255 - Manual (Page 15)

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All input and output impedances and levels are to be found in the TECHNICAL
SPECIFICATION.
All inputs to, and outputs from AD255 are to be found on the connector panel.
Module connector (4) accepts balanced microphones and balanced line-level inputs.
XLR (input & output)
Pin 1 Shield
Pin 2 Signal +
Pin 3 Signal -
In the case of unbalanced line-inputs and outputs, pins 1 & 3 should be connected.
This will not lead to a loss of level.
Channel direct outputs (11) are at line level and unbalanced
Main stereo (2), mono (1) and auxiliary outputs (10) are transformer balanced and are
at line level.
The auxiliary outputs appear on two ‘A’ type stereo jacks.
The electronically-balanced stereo tape-return enters the mixer on two standard, ‘A’
type stereo jacks (9); left and right. Adjacent is the input calibration preset. For a
0dBu return signal, the system is calibrated when the preset is fully counter-clockwise.
From that point 20dB gain is available for lower level signals.
Unbalanced headphone monitor output appears on an ‘A’ type stereo jack (5). This
output is capable of driving 25R at 0dBu.
STEREO BALANCED JACK
STEREO UNBALANCED JACK
Tip Signal + Tip Left signal
Ring Signal - Ring Right signal
Sleeve Shield Sleeve Shield
The 6-pin XLR connector, SUB (8), carries all signals to and from an outstation.
Reverse-talkback level may be set by REV TB preset (3).
XLR
Pin 1 Shield Pin 4 Ret +
Pin 2 Send + Pin 5 Ret -
Pin 3 Shield Pin 6 Control
The unbalanced send is low impedance with a capability of driving headphones of 25
ohms impedance or greater.
The balanced (or unbalanced) signal from the outstation may be at mic level or line
level. The mixer leaves the factory set for a line-level return, but the gain of the return
amplifier may be increased by 20dB via the DIL switch on the sub board attached to
the connector panel. Preset (9) controls the level of the return - which feeds on to the
PFL mixing buss and is routed by grounding the control line (Pin 6) at the external
source.