Operating Elements; Protection Circuit - Crunch Ground Pounder GPX1200.4 User Manual

AUDIO SIGNAL CABLES
When installing the audio cables between the RCA outputs of the headunit and the RCA inputs of the amplifier,
the audio and power supply cables should, if possible, not be routed along the same side of the vehicle. We
recommend a separated installation, e.g. routing the power cable through the cable channel on the left side
and the audio cables through the cable channel of the vehicle on the right side or vice versa. This prevents
interferences due to crosstalk into the audio signal.
SIGNAL OUTPUTS TO CONNECT ADDITIONAL AMPLIFIERS
The input signal on the INPUT CH1/2 jacks (Fig. 1,5) will be routed in stereo to the output jacks OUTPUT CH1/2
(Fig. 1,6). Thus the OUTPUT jack allows the connection of a additional amplifier.

OPERATING ELEMENTS

INPUT SENSITIVITY CH1/2 & CH3/4
Turn the GAIN (Fig. 1,4 CH1/2 and fig. 1,8 CH3/4) controller of the amplifier to the MIN position. Then turn the
volume controller of the headunit to 80 - 90% of its full setting. Now turn GAIN clockwise until you hear some
distortion. Then turn back the GAIN slightly until you hear a cleaner sound.
VARIABLE HIGH PASS FILTER CH1/2 & CH3/4
If the amplifier is to be used for mid-range/tweeter loudspeakers, set the switches FILTER (Fig. 1,3 CH1/2 and
fig. 1,11 CH3/4) to HPF. Then set the desired crossover frequency on the HPF controller (Fig.1,2 CH1/2 or fig.
1,12 CH3/4). Thus to that only the frequencies above the chosen crossover frequency will be amplified. This
effectively minimizes distortions and overloads at lower frequencies. A good point to start is at 125 Hz.
If you use loudspeakers (>20 cm) set FILTER (Fig. 1,3 CH1/2 and fig. 1,11 CH3/4) to FULL. In this case, the
HIGH PASS controllers (Fig.1,2 CH1/2 or fig. 1,12 CH3/4) are without function.
VARIABLE LOW PASS FILTER CH3/4
If the amplifier is used to drive a subwoofer, set the switch FILTER (Fig. 1,11 CH3/4) to „LPF". Set the desired
crossover frequency by using the controller (Fig. 1,10 CH3/4). Thus to that only the frequencies below the cho-
sen crossover frequency will be amplified and the subwoofer plays more precised and efficient.
SWITCHABLE BASS BOOST CH3/4
By using the BASS BOOST switch (Fig.1,9 CH3/4) you are able to increase the bass level by 6 or 12 dB.
Attention: Use the BASS BOOST wisely!

PROTECTION CIRCUIT

The POWER/PROTECTION LED (Fig. 1,1) lights up green, if the amplifier is in operation.
The POWER/PROTECTION LED (Fig. 1,1) lights up red, when the amplifier is overheated, or a short circuit
occurs resp. a too low impedance load is connected to the speaker outputs. If this events, the internal built-in
protection circuit shuts down the amplifier automatically. The amplifier should work again properly after you
have solved the problems.
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