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MTX amps are legendary for their performance and reliability, and the Thunder4000 amps are no exception. For loads of power, the MTX Thunder4202 uses a "pure N-channel" design with a MOSFET power supply. This efficient circuitry turns most of the available energy into usable wattage, instead of the heat generated by most amps.

Intelligent Surface Mount Technology makes the amp vibration-resistant, enhancing the amp's long-term reliability. Speaker-level inputs feature SmartEngage, which turns the amp on when it gets signal from the receiver.

  • stereo or bridged mono output
  • Tri-way capable (Tri-Way crossover required)
  • 100 watts x 2 at 2 ohms
  • 200 watts x 1 in bridged mode
  • requires 10-gauge power and ground leads — wiring and hardware not included with amplifier
  • PWM MOSFET switching power supply
  • Intelligent Surface Mount Technology for cleaner sound and greater reliability
  • selectable 85 Hz high-pass/low-pass crossovers, 18 dB/octave
  • preamp outputs
  • speaker-level inputs with SmartEngage (turns the amp on when it detects signal from the receiver, eliminating the need for a separate turn-on lead from your receiver)
  • 9-3/4"W x 2-1/8"H x 9-3/4"D
  • 1-year warranty

MTX Thunder4202 Reviews

Hands-on research

What's in the box?

Download owner's manual

  • Black MTX Thunder 4202 amplifier with chrome trim
  • 30-amp blade fuse (installed)
  • Speaker level input wiring harness
  • Warranty registration and customer survey card
  • Performance certificate
  • Owner's manual (English/French/Spanish/German)
  • MTX Audio sticker
  • Bridged impedance warning sticker.

Product Research

Inputs, Outputs and Controls


Class A 100% Discrete Driver Circuitry Topology: The preamp stages use Class A topology for low distortion and a high damping factor; the result is tight, controlled bass.

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.

Smart-Engage™: When using the speaker-level input, the amp automatically turns on when it senses signal from the head unit, eliminating the need for a remote turn-on connection. In many cases, this feature will allow you to install the amplifier without the need to remove your radio.

Internal Crossover: The built-in crossover is an 18dB/octave, 85Hz crossover. It can be set for high-pass or low-pass operation, or it may be turned off for full-range output.

Preamp Outputs: There is one set of isolated, full-range preamp outputs for adding another amp.

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.

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; this helps prevent ground loops.

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.

Inputs, Outputs and Controls

Left Side of the Amplifier

  • Gain control: allows you to match the input sensitivity of the amplifier to the particular source unit you are using
  • Line-In: RCA stereo jacks
  • Line-Out: RCA stereo jacks
  • Crossover Switch: lets you select high pass, low pass, or full range operation
  • Speaker Level Input: a 4-pin input for use with the included speaker-level input harness; allows the amp to operate with source units that do not have preamp outputs

Right Side of the Amplifier

  • Speaker Outputs: screw terminals (each terminal is 0.34" wide)
  • BATT (power): screw terminal (terminal is 0.54" wide)
  • GND (ground): screw terminal (terminal is 0.54" wide)
  • REM (remote turn-on): screw terminal (terminal is 0.34" wide)
  • Fuse: 30-amp blade fuse

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.