Allen&Heath GR8A - Manual (Page 6)

6 GR8A U SER G UIDE
Front Panel Controls
POWER switch Turns the amplifier on or off. I = on, 0 = off.
TEMP indicator Shows the status of the amplifier temperature
management system:
Green Low temperature Amplifier on, cooling fan stopped
Amber Medium temperature Cooling fan running at slow speed
Red High temperature Cooling fan running at fast speed
SIG indicators Each channel has a 3-colour indicator to monitor the
output signal level:
Green Signal present Turns on at 140mW into a 4 ohm speaker.
Amber Medium level Turns on at 10 watts into a 4 ohm speaker.
Red Signal peak Turns on just before clipping
STANDBY indicators Each channel has a red indicator that lights when
it is in standby mode with its output stage muted. All channels are held in
standby mode for a few seconds when you switch the unit on. This
prevents thumps in the speakers while the power rails stabilise. Selected
channels can be put into standby mode using the rear panel REMOTE
STANDBY connector switching facility.
BRIDGE MODE indicators Each pair of channels has a green indicator
that lights when it is configured for bridged operation using the rear panel
OUTPUT MODE switches.
LEVEL controls Each channel has a rotary control that adjusts its level
from fully off to maximum sensitivity. In bridged mode the odd numbered
channel control sets the overall level and the even numbered control is not
used. Use the level controls to match the amplifiers to the connected
source equipment, set maximum volume allowed, or adjust the balance
between different outputs. Blanking plugs are provided for situations
where tamper-proof level setting is required. Simply set the level, pull off
the knob and push in the blanking plug. The level can be adjusted without
refitting the knob by pulling out the plug and using a small slotted
screwdriver to turn the control shaft.
MONITOR switch 8 Position switch to select one of the 8 amplifier
outputs as the monitor source for headphones or local speaker. This lets
you check the selected amplifier from its speaker terminals attenuated
through a series resistor to match the sensitivity of the headphones.
PHONES socket Plug in headphones to listen to the selected monitor
source. This is a TRS jack socket wired for standard stereo headphones.
The selected channel is monitored in mono.
SENS switch Adjusts the monitor output to match the sensitivity of the
connected headphones. This is an underpanel tamperproof switch to
prevent accidental operation. Use a pen or similar pointed object to
change its setting. The output level is increased when the switch is in its
pressed position.