Operation; Controls - ATC P4 Four User Manual

I
NSTALLATION
The P4 is designed to be free standing or rack mounted (using suitable shelving). Consideration
should always be taken to ensure adequate ventilation. The cooling of the amplifier is achieved by
forced ventilation at the rear of the amplifier with an exhaust vent at the front of the amplifier. DO
NOT obstruct either front or rear vents or enclose the amplifier.
When switching from standby to normal operation it is expected that you will hear a mild thump
from the amplifier as the main power transformer energises. If more than one amplifier is to be
connected to the same power outlet it is recommended that they are switched on in sequence –
important if switching by remote.
C
OOLING
The fans will only run when the heatsink temperature reaches approximately 30°C and they will
continue to run even in standby mode until the temperature has dropped to approximately 20°C.
C
ONTROLS
Control and operation of the P4 is simple once all connections have been made.
Mains power is isolated by a toggle switch on the rear of the amplifier and must be in the on
position to allow operation. To activate the amplifier press the standby button once, this will start
the power up sequence :-
Front Panel Controls
normal

operation

when lit
blue
status/error
indication
tri-colour
push button
Standby
Failure to start will be indicated by a steady orange LED only, this state can be caused by a high
temperature or DC in one of the amplifiers, if neither of these conditions are true then a control
failure has happened and service is required.
During normal operation the Blue LED will remain lit. If the amplifier is being driven hard a RED
indication will show operation of the gain reduction circuits. Any other fault will cause the amplifier
to shutdown showing an orange indication with no blue LED.
If a fault has occurred the amplifier can be restarted by pressing the standby button, in the case of
an over-temperature the amplifier will have to be left to cool down before a restart.
The amplifier can be returned to standby be pressing the standby button, the blue LED will
extinguish and only a green LED will be displayed.
1. Button pressed
2. Green LED turns to Orange
3. Blue LED starts flashing (protection circuit checks)
4. Orange turns Red (mute circuit released)
5. Red extinguishes
6. Blue LED stays constant (normal operation)
O
P E R A T I O N
5