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AMPLIFIER OPERATION GUID
E
Setup
Before operating the
A
series amplifier
s
, check the mains supply voltage and connect the IEC inlet to the mains power
supply using the power lead supplied (or equivalent). Ensure that the cooling vents at front and rear are not covered or
obstructed in any way with adequate space for air-flow through the unit.
Each side of the
A
series amplifier
s
can be operated as an independent pair of channels or as a single combined output
in Bridge mode. Set the mode using the selector switch for the relevant pair of channels (rear panel 7 & 10).
Bridge mode offers the option of operating the
A
series
as a stereo amplifier into 2 larger 8Ω speakers.
It is also possible to operate one side in Bridge mode to give 1 high output channel with the other side in stereo, which
can be useful to power a large sub and a pair of satellite speakers (left + right).
Standard dual stereo or quad mode
Connect speakers to
Channel 1
,
2
,
3
and
4
outputs via the SPK connectors (rear panel 2, 3, 4 & 5)
For standard output mode SPK wiring, connect
+
and
-
wires to pins
1+
and
1-
(most common configuration)
Ensure that the combined load on each channel is no lower than 4Ω (for speakers in parallel, 8Ω + 8Ω = 4Ω)
Connect line level inputs to the
CH 1
,
2
,
3
and
4
XLR inputs (rear panel 6, 8, 9 & 11)
Each output is governed by its own channel gain control on the front panel.
Bridge mode
Bridge mode is different to standard mode in that it combines 2 of the output channels to a single mono output.
This mode enables double the power to a single speaker output compared with standard mode.
The difference is that the speaker load must be no lower than 8Ω, whether a single speaker or combined load.
Bridge mode can be useful especially when driving a large, high power subwoofer.
Connect the speaker(s) for Bridge mode to the
Channel 1/3
SPK output(s).
Note that the SPK wiring in Bridge mode is different to standard mode.
Connect the “
+
” speaker wire to amplifier
1+ (rear panel 5)
and the “–” speaker wire to amplifier
2+ (rear panel 5)
.
Note: For reference, this wiring is printed on the rear panel. Incorrect speaker wiring can damage the amplifier!
In Bridge mode,
CH 1
and
3
XLR inputs send mono signal to the
CH 1
and
3
SPK outputs (pins 1+/2+)
Operation
With channel gain controls (front panel 1, 5, 7, 11) turned fully down (anti-clockwise), switch on the power (front panel
12) and the LED POWER indicator will light (front panel 6)
Pla
cing
the input signal into the connected channel inputs, gradually increase the relevant gain controls (only CH 1 and
3 will have an effect in Bridge mode). The amplified signal should be heard through the speakers and the SIG indicators
(front panel 2, 4, 8, 10) should respond to the audio output. Increase the volume controls to the required level.
Alongside the SIG indicators are CLIP indicators, which should only light very briefly on the loudest transients or spikes
in the audio. If the CLIP LEDs light for more than a fraction of a second at a time, the volume controls should be turned
down or input signal will need to be reduced.
Before powering down, turn down the volume controls to avoid loud pops or noises through the speaker.
