Audio Developments AD 245, Manual, Page: 18 / 26

17
The Microphone/Line input module functions are as follows: Switch (1) selects 48v
phantom and 12v tonader power for condenser microphones.
Powering may be
selected before or after connecting the microphone, but switch off all powering on
unterminated modules to ensure unconditional stability of the mixer. For complete
safety of external equipment, switch off microphone power before connecting a line-
level signal.
Phase change (4) is pre transformer and operates on microphone and line inputs.


is the normal position.
The high-pass filter is pre transformer and, similarly, operates on microphone and line
inputs. In this position the filter protects the transformer from low-frequency saturation
caused by wind, traffic, air conditioning etc. Operating frequencies are to be found in
the TECHNICAL SPECIFICATION.
The high-pass filter operates independently of
the equaliser.
The input gain of the microphone amplifier is set by the 6-position switch (3). The
range of this control is 50dB in 10dB steps. For line-level signals, an input attenuator
is inserted via switch (2).
Following the microphone amplifier is the simple, but effective, equaliser which has
been retained from the original PICO - selector switch (6).
Because of the inherent
inaccuracy of the centre-detent mechanism, it is not Audio Developments’ practice to
fit such devices to equaliser amplitude controls - HF (11), MF (12), LF (13).
A panoramic potentiometer - panpot - (7) routes the module’s signal proportionately
between the left and right mix busses.
Pre-fader listen (8) with its LED indicator (9) routes the module’s signal to the
monitor/PFL mix buss for auditioning on headphones.
An overload LED (10) illuminates 3dB before clipping at the input to the fader.
The Penny & Giles fader (14) is calibrated 10dB from its fully open position,
allowing the operator to work with 10dB of gain in reserve. Faders on adjacent
modules can be coupled for stereo operation by the use of standard ganging clips.