MTX Audio TH Series TH90-4 360W RMS 4-Channel Class A-B Amplifier - Manual (Page 3)

Control Panel :
Gain Control (GAIN) : The gain control matches the input sensitivity of the amplifier to the source unit being used.
The operating range varies from 100mv to 6V.
Adjusting the gain
1. Turn the gain control on the amplifier all the way down (counter clockwise).
2. Turn up the volume control on the source unit to approximately 3⁄4 of maximum.
3. Adjust the gain control on the amplifier until audible distortions occurs.
4. Adjust the gain control down until audible distortion disappears.
5. The amplifier is now calibrated to the output of the source unit.
Low-Pass High-Pass X-Over Switch (X-OVER) :
In “LPF” position, the active low pass (LP) x-over is turned on
In “HPF” position, the active high pass (HP) x-over is turned on
In “FULL” position, the x-over is turned off
High Pass X-Over Frequency Control (HPF) :
Used to select the desired high-pass (HP) x-over frequency. The frequency is adjustable from 40Hz to 400Hz.
Low Pass X-Over Frequency Control (LPF) :
Used to select the desired low-pass (LP) x-over frequency. The frequency is adjustable from 40Hz to 400Hz.
RCA Inputs (INPUT) : These RCA inputs are used with source units that have RCA or Line level outputs. (Source
units need a minimum level of 100mV output for proper operation of the amplifier).
MTX recommends only high quality twisted pair cables (such as StreetWires) to decrease the possibility of
radiated noise entering the system.
The Power LED will illuminate when the unit has power from a 12V source and 12V is applied to the remote
terminal. The Power LED will blink when the amplifier enters protect mode due to an electrical short or excessive
thermal incident (see Troubleshooting).
Speaker level inputs (HLI) : This input will allow the amplifier to operate from source units with speaker-level
outputs. Output speaker leads from the source unit should be tied directly to the wire harness provided with
the amplifier.
Note : When speaker level inputs are used, a remote turn on wire must be used to switch the amplifier On and Off.
Power Terminal (+BATT) : This is the main power input for the amplifier and must be connected directly to the positive
terminal of the vehicles battery for proper operation. Use caution when installing (+12) power cable in the vehicle.
Avoid running this cable parallel with RCA cables, antennas, or other sensitive equipment due to massive currents
that can induce noise into the audio system. It is also very important to have a tight, secure connection for maximum
performance. MTX recommends using 4 AWG power wire with the MTX TH90.4 amplifier.
Remote Terminal (REM) : The amplifier can be turned on by applying 12 volts to this terminal. Typically this
voltage is supplied by a wire from the source unit marked “remote” or “power antenna”.
Ground Terminal (GND) : A proper ground is required for your amplifier to operate at peak performance. A
short ground cable the same diameter as the power cable should be used to attach the ground terminal
directly to the chassis of the vehicle. Always remove paint, dirt or debris to expose bare metal where the
ground will be attached.
Speaker Terminals (SPEAKER) : Connect speakers to these terminals. Observe speaker polarity throughout the
system. Improper phase can result in loss of bass response and/or poor overall sound quality.
Bridge Mode : When bridging the amplifier, use the right positive terminal and the left negative terminal only.
Warning : do not bridge the amplifier with an impedance lower than 4 ohm.
Fuse (FUSE) : If the fuse blows, replace them with the same value. Never use a higher rated fuse!
Caution : fuses are located under the amp.