Input Sensitivity; Protection Circuit - Crunch GTS Series User Manual

HIGH LEVEL INPUTS & AUTO TURN ON
The high level inputs under HIGH LEVEL INPUT (Fig. 5) is suitable to connect the device input with speaker
wires, if your head unit is not equipped with pre-amplifier RCA outputs. Extend therefor every regarding speak-
er cable from your head unit with appropriate speaker cables from your car audio retailer to the mounting
location of the amplifier. Then connect the each matching loudspeaker cable with the cables of the included
High Level Input jack.
CAUTION: Never use the high level inputs and the RCA inputs at the same time. This may damage the
device seriously.
The amplifier detects a voltage rise (6 Volts) with a so called "DC Offset" over the connected input signal on the
high level inputs under HIGH LEVEL INPUT (Fig. 5) when the head unit will be switched on. Hence, the ampli-
fier will also be turned on. As soon as the head unit will be turned off, the amplifier turns also automatically off.
In this case the turn-on connection REM (Fig. 2,2) is not needed.
NOTE: The Auto Turn On function usually works with 90% of all head units, because they are equipped with
"High Power"-outputs. Only with a few older and head units the Auto Turn On function is not working.

INPUT SENSITIVITY

Turn the controller LEVEL INPUT (Fig. 1,84) of the amplifier to the MIN position. Then turn the volume controller
of the head unit to 80 - 90% of its full setting. Now turn LEVEL INPUT clockwise until you hear some distortion.
Then turn back the LEVEL INPUT slightly until you hear a cleaner sound.
VARIABLE HIGH PASS FILTER
If the amplifier is to be used for mid-range/tweeter loudspeakers, set the switch X-OVER (Fig. 1,3) to HP. Then
set the desired cross-over frequency on the HIGH PASS controller (Fig. 1,2). Thus to that only the frequencies
above the chosen cross-over 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 big loudspeakers (>20 cm) set X-OVER (Fig. 1,3) to FULL. In this case, the HIGH PASS controller
(Fig. 1,2) is without function.
VARIABLE LOW PASS FILTER
If the amplifier is used to drive a subwoofer, set the switch X-OVER (Fig. 1,3) to LP/BP. Set the desired cross-
over frequency by using the controller LOW PASS (Fig. 1,4). Thus to that only the frequencies below the cho-
sen cross-over frequency will be amplified and the subwoofer plays more precise and efficient.
In LP/BP mode, the controller HIGH PASS (Fig. 1,2) can also be used to limit the frequency response down-
wards, for example to produce a bandpass/subsonic signal. NOTE: If the controller HIGH PASS (Fig. 1,2) is
set higher than the he controller LOW PASS (Fig. 1,4), no audio signal is heard.
VARIABLE BASS BOOST
By using the controller BASS BOOST (Fig. 1,7) you are able to increase the bass enhancement from 0 to 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 respective 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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