Allen&Heath GR8A - Manual (Page 7)

GR8A U SER G UIDE 7
Rear Panel Controls and Connectors
MAINS INPUT The GR8A AC mains voltage setting is factory wired
according to country of order. An IEC power lead with moulded plug
suitable for your mains outlet is supplied with the unit.
Check that the mains voltage marked on the rear panel
matches your local supply.
Read and heed all the warnings printed on the rear panel and
at the start of this user guide.
BATTERY INPUT An emergency back-up supply such as battery or UPS
is a common requirement for public announcement installations. The
GR8A has a 4way Phoenix type pluggable screw terminal input to connect
two 24V DC batteries for back-up power in the event of a loss of mains
supply. Use heavy gauge wire and observe the correct polarity according
to the legend printed above the connector. A mating connector is provided
with the unit.
SIGNAL INPUTS Each channel has a 3-pin female XLR chassis socket
input. These are electronically balanced and wired pin 2 = hot. Input
sensitivity is +4dBu for rated power output. Good quality 2 core screened
signal cable should be used for these inputs to avoid signal degradation or
interference pickup over long cable runs. Use balanced connections
where possible.
INPUT MODE switches Three tamperproof underpanel switches
configure the inputs to allow different combinations of common input
sourcing. Use these when you have one or two sources feeding several
channels. This eliminates the need for custom multi-plug input cables.
8 Independent No common sourcing
4 way mono Input 1 to channels 1–4. 5-8 independent
8 way mono Input 1 to channels 1–8
2 way stereo Input 1 (L), 2 (R) to channels 1/2, 3/4
4 way stereo Input 1 (L), 2 (R) to channels 1/2, 3/4, 5/6, 7/8
MONITOR TRS output with tip = signal, ring and sleeve = ground.
Follows the source selected on the front panel MONITOR switch to feed a
small local loudspeaker or monitoring system as an alternative to the
headphones. The speaker voltage is reduced through a series resistor to
prevent overload. Further attenuation may be needed if this output is to
feed an external amplifier or other line level equipment input.