L2 Audio PA1000 Owner's Manual - page 5
2.
Input GND LIFT (ground lift) switch removes the ground connection to all input connectors.
This can solve hum loop problems when connecting equipment with different A.C. supplies.
Under no circumstances should the electrical safety ground (earth) from the A.C. supply be
disconnected.
3.
PARALLEL INPUTS links Channel 1 input to Channel 2. A single input signal will now supply
both channels. The volume levels of each channel can still be adjusted individually.
4.
35Hz HIGH PASS FILTER reduces the level of very low frequency signals reaching the
speakers, improving bass clarity and power handling. It is recommended that this filter is
always used for live P.A/Sound reinforcement. Ported / Vented / 'bass reflex' speaker
cabinets can be damaged if driven with high power low frequency. The filter has an 18dB /
octave roll off slope.
5.
LIMITER OFF disables the clip limiter circuit. At maximum power output, the limiter virtually
prevents amplifier clipping, minimising audible distortion. It should only be turned off in
specific applications, as serious speaker damage can occur if the amplifier is allowed to
clip
regularly.
6.
X-OVER turns on the internal two way crossover circuit. The crossover splits the audio band
into high frequencies, suitable for mid/high speakers and low frequencies suitable for bass
speakers. If the crossover function is not required this switch should remain off (out
position).(Not applicable to PA600).
7.
The FREQUENCY switch selects the crossover frequency between 150Hz and 100Hz. For
most systems 150Hz is recommended but sometimes, typically when using 18" subs, will
work better with 100Hz.
8.
HI LO selects which signal from the crossover the amplifier receives. When HI (out position)
is selected only frequencies above 100 or 150Hz feed the amplifier. When LO (in position) is
selected only frequencies below 100 or 150Hz feed the amplifier.(Not applicable to PA600).
9.
XOVER OUTPUT sockets allow the high or low frequencies from the crossover circuit to
feed additional amplifiers. (Not applicable to PA600).
10. BRIDGE
mode combines the output power of both amplifier channels into one load. This is
useful when driving a single, high powered speaker. Only channel1 output socket connects
to the speaker but needs to be wired +1 and +2.
11. SPEAKER OUTPUTS. Each channel uses SPEAKON NL4 connectors. Always ensure speaker
cables are wired the same way otherwise the speakers will be out of phase which results in
a slight loss of bass response.
12. CIRCUIT BREAKER will only activate if the amplifier has developed a fault or been driven
too hard. The button on the circuit breaker will protrude about ¼” (6mm) when tripped.
Check speaker wiring and load before re-setting. To reset turn off the amplifier power
switch and push in the reset button. If the breaker trips again, the amplifier could have
developed a fault. If this happens refer the amplifier to a qualified service technician.