Control Panel
Gain Control - The gain control matches the input sensitivity of the amplifier to the source unit being used.
The operating range varies from 250mv to 5V.
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 distortion occurs.
4. Adjust the gain control down until audible distortion disappears.
5. The amplifier is now calibrated to the output of the source unit.
Bass Boost Control:
Allows user to adjust the bass boost between 0dB - 12dB at 40Hz.
Subsonic Filter Control:
Used to select the desired subsonic filter frequency. The frequency is adjustable from 30Hz to 50Hz.
Low Pass X-Over Frequency Control :
Used to select the desired low-pass (LP) x-over frequency. The frequency is adjustable from 40Hz to 200Hz.
RCA Inputs - These RCA inputs are used with source units that have either RCA/Line level or speaker level outputs.
(Source units need a minimum level of 250mV 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.
EBC Port (External Bass Control) - The Remote Subwoofer Level Control (EBC) plugs directly into this port, while the
EBC itself can be placed anywhere in the vehicle for on demand bass adjustments. EBC is included.
Power On/Protection LED - The LED illuminates red when the amp is switched on. When the amps is in short circuit
or thermal protection, the LED illuminates orange. You need to switch the amp Off and On to restart.
Speaker Terminals - 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.
Ground Terminal – 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.
(+12V) Power Terminal - 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 RT250D amplifier
Remote Terminal – The amplifier is 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”.
Fuses - When fuses blow, replace them with the same value. Never use a higher rated fuse !
