Audio Developments AD146 - Manual (Page 5)

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Fuses - to protect the mixer and internal power supply are mounted on the power
supply/converter board. Access is gained by removing the output module. 20mm, 1A
ANTI-SURGE HRC fuses are used - one for the internal battery power supply and one
for the external DC supply.
Until the mixer has been acceptance tested we strongly recommend that modules are
not removed for adjustment. If adjustments are necessary, refer to the section on
adjustments and calibration. All customer functions are external, except the following.
Limiter threshold - is set at the factory at +8dBu (PPM 6), but an internal preset
potentiometer allows adjustment to any other level above 0dBu.
The limiters are to
be found on the left-hand PCB of the output module. Presets are also available for
adjusting limiter attack and release times.
Reverse-talkback output - is set at the factory to provide a mono mix of monitor 1 left
and right outputs, rather than mute, when the main talkback switch is released.
This
function can be disabled by the DIL switch to be found on the left-hand PCB of the
monitor module.
Line-up tone - at 1kHz and 10kHz is calibrated on the meters to PPM4, giving a line
output level of 0dBu with L/R and AUX 1/2 controls set to maximum.
NOTE - PPM4
refers to the mark on a BBC PPM Scale. Other meter scales have a different mark
at 0dBu level. Alternative calibration levels are possible via the internal preset.
RH-output ident - as an alternative to continuous tone on all main outputs; B & D
outputs can be pulsed with tone for 3 seconds.