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MTX Thunder311D

155W x 1 Mono Subwoofer Amplifier

Item # 236T311D

High-level performance is what MTX amplifiers are all about!

Find what Fits your vehicle

High-level performance is what MTX amplifiers are all about!

Discontinued item

Item # 236T311D

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About the MTX Thunder311D

High-level performance is what MTX amplifiers are all about! The sound pros at MTX subject each Thunder amp to rigorous bench testing before they'll let it ship, and they pack each model full of features designed with you, the music lover and audio enthusiast, in mind.

High-level performance is what MTX amplifiers are all about! The sound pros at MTX subject each Thunder amp to rigorous bench testing before they'll let it ship, and they pack each model full of features designed with you, the music lover and audio enthusiast, in mind.

Even though it's the smallest of the Thunder mono amps, the Thunder311D is ready and willing to deliver some serious bass. At 4 ohms, you get 155 watts RMS. Hook up a 2-ohm load, and the output doubles to 310 watts! A built-in low-pass filter (85 Hz at 18 dB per octave) eliminates the need for an outboard crossover.

How does MTX do it? Heavy-duty, nickel-plated terminal block connectors direct as much current as possible into the amp. Inside, high-powered transformers and patented PWM MOSFET switching power supplies deliver big output for dynamic sound. Intelligent Surface Mount Design isolates the various amp sections on the circuit board for greater stability and lower noise levels. The upshot — you enjoy deep, pounding bass.


  • 155 watts x 1 at 4 ohms
  • 310 watts x 1 at 2 ohms
  • requires 8-gauge power and ground leads — wiring and hardware not included with amplifier
  • Adaptive Class D Technology
  • 85 Hz low-pass crossover, 18 dB/octave
  • preamp outputs
  • PWM MOSFET switching power supply
  • gain control
  • selectable Thunder EQ bass boost (0/6/12 dB at 40 Hz)
  • speaker-level inputs with SmartEngage (turns on the amp when it detects signal from the receiver, eliminating the need for a turn-on lead)
  • 8-1/16"W x 2-1/4"H x 9-13/16"D
  • 1-year warranty

What's in the box:

  • 1 Mono-block amplifier
  • Speaker-level input harness
  • Owner's manual
  • Amplifier Input/Output Connections sheet
  • Amplifier Performance Certificate
  • MTX Audio sticker
  • Mono Amplifier Impedance Requirement sheet (attached to inside packaging)

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More details on the MTX Thunder311D

Mark G.

Product Research

Inputs and Outputs
Manual Correction


Patented PWM MOSFET Switching Power Supply:  This type of power supply is used for maximum power output and protection.

Adaptive Class D Technology: While typical Class D amps tend to generate high frequency energy that must be filtered to prevent harmonic interference in the FM radio frequency range, Adaptive Class D Technology directs the amp's switching energy away from FM radio ranges as the amp's load and output increases. This improves the amp's overall signal-to-noise ratio and eliminates interference generated by more common Class D amps.

Pure N-Channel Design: The pure N-channel design is more linear than typical N-Channel designs, so the speaker you connect to the amplifier will be better controlled. The signal travels through fewer parts so the signal-to-noise ratio is enhanced, the power rating is better, and the amp runs louder, longer.

Low Impedance, High Power Transformers: These provide more power and produce less heat.

Smart-Engage: If you're planning to keep your factory radio and use the amp's speaker level inputs, Smart-Engage senses the source voltage from the factory radio, meaning you won't have to run a separate turn-on lead and won't necessarily have to remove the factory radio during installation.

Real-time Computerized Protection Circuit: The protection circuit makes sure you amp is operating within safe parameters for maximum power and protection.

Acoustically Seamless Turn-on/Turn-off: A circuit that prevents turn-on/turn-off "thump" is included to eliminate turn-on/off noise.

Iso-Feet: Four rubber Iso-Feet are attached to the amplifier. The rubber feet let you mount the amp securely, while preventing the mounting screws from coming into contact with the amp's chassis.

RCA Outputs: In addition to the set of preamp inputs, there is a set of buffered RCA preamp outputs, providing a full-range stereo signal. The outputs allow you to daisy-chain one bass amplifier to another.

Intelligent Surface Mount Technology: Features substantially shorter internal and external lead lengths, reducing stray capacitance and inductance, which results in cleaner and more accurate musical reproduction with less noise interference.

Thunder EQ: Thunder EQ is a selectable Bass Boost (0dB, +6dB, +12dB) centered at 40 Hz. 

Crossover: This amplifier is equipped with a fixed 85Hz, 18dB/octave, low-pass crossover that is always active.

Terminals: The terminals are nickel-plated, heavy-duty screw terminal connectors.

Performance Certificate: MTX tests each amplifier, and the technician records the "actual" power output on the Certified Performance Certificate included with each amp. The amp must meet or exceed the rated specification in order to leave the factory.


Dynamic Power Measured at 14.4 Volts DC:
  • 155 Watts x 1 into a 4 Ohm load
  • 310 Watts x 1 into a 2 Ohm load

RMS Power Measured at 12.5 Volts DC:

  • 100 Watts x 1 into a 4 Ohm load
  • 200 Watts x 1 into a 2 Ohm load

Inputs and Outputs

Left Side of Amplifier:

  • Line In: RCA stereo jacks
  • Line Out: RCA stereo jacks
  • Speaker Level Input: a 4-pin input for use with the included speaker-level input harness

Right Side of Amplifier:

  • +BATT: (power): screw terminal (terminal is 0.54" wide)
  • REM (remote turn-on): (terminal is 0.34" wide) 
  • GND (ground): screw terminal (terminal is 0.54" wide)
  • Speaker Terminals: there are two sets of terminals (labeled Speaker 1 and Speaker 2), but they are wired internally in parallel and they provide mono output (terminals are 0.34" wide)

Manual Correction

Fuse Rating: The amplifier comes with a 30-amp fuse inserted into the chassis, and just above the fuse location, it indicates "30A". However, the label attached to the bottom of the amp, the manual and the carton all indicate a 35-amp fuse.

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