An MTX Road Thunder amp puts your music up front and in your face — in a great way. You won't stop smiling when you finally hear all the musical details and and feel the awesome bass that your old system just couldn't reproduce.

Rockin' with 500 watts
The RT500D mono sub amp will rock your ride with up to 500 watts RMS of clean bass power. You can use the variable frequency filters and bass boost to match this amp to your particular subwoofer system.

Reliable performance
When the beat gets hot during heavy play, this amp's inner works stay cool by shedding heat efficiently through a tough, extruded aluminum top cover and heatsink assembly. This Road Thunder amp features speaker-level inputs with special circuitry that turns the amp on when it senses an incoming signal, which come in handy if you're hooking it up to a factory radio.

Product Highlights:

  • mono subwoofer amplifier
  • 250 watts RMS x 1 at 4 ohms (500 watts RMS x 1 at 2 ohms)
  • CEA-2006 compliant
  • frequency response: 20-200 Hz
  • adaptive Class D amp technology
  • variable low-pass filter (40-200 Hz, 12 dB/octave)
  • variable subsonic filter (20-50 Hz, 12 dB/octave)
  • variable bass boost (0-12 dB at 40 Hz)
  • External Bass Control included
  • preamp and speaker-level inputs
  • Smart Engage turns on amp when signal arrives through the speaker-level inputs
  • fuse rating: 30A x 2
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 11-3/8"W x 2-1/16"H x 8-3/4"D
  • warranty: 5 years (free repair or replacement for 2 years; prorated replacement for years 3 through 5)
  • Our 60-day money-back guarantee

My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

MTX Road Thunder RT500D Reviews

Average Customer Review:

9 reviews
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Written By JZM, California on Sunday, December 14, 2014

Ordered one from a different online retailer. All my wiring was professionally done. Then after 10 minutes of usage the amp goes straight to green protection light...

Pros: Works great with 8 gauge wire. Also has enough to power two 12" subs

Cons: Poor quality

MTX Road Thunder RT500D

Written By Anonymous, Westminster, MD on Saturday, December 13, 2014

Crutchfield Customer Review (What's this?)

This unit is easy to set up and sounds great!!

Dont buy

Written By Anonymous, Boston, MA on Tuesday, July 22, 2014

Crutchfield Customer Review (What's this?)

Had this for about 2 weeks worked great first 3 days i had it after that it would cut out for long periods of time. Gets extremely hot . I sent it back and got the Alpine MVR M500 i love it recommend it to anyone looking for a cheaper amp with alot of power. Its the best extra 30 dollars ive ever spent

Pros: Not many

Cons: Runs hot, takes up alot of space wouldnt recommend to anyone to be completely honest

MTX RT500D Amp

Written By calllaw, Dayton, Ohio on Sunday, July 06, 2014

Crutchfield Customer Review (What's this?)

see pros and cons. !!! below.

Pros: Nice and compact. fits neatly in a small area. Good looking unit. wiring is all on one side of Amp which is the best set-up, as you can tuck it in a corner and not need access to both sides(which uses much more room. priced very reasonably.

Cons: but I think it's Rms is over rated. I think this is more like a 300 RMS, also amp gets extremely hot when wired in 2 ohm mode. Extreme heat ultimately leads to unit failure.


Written By K. Wilks, Saint Clair Shores, MI on Thursday, June 12, 2014

Crutchfield Customer Review (What's this?)

I bought this instead of getting my MTX 6500D repaired because of the price, and the fact it came with "free" earbuds. What a disappointment. The power ratings on both amps are identical, but this new amp sounds like it's putting out half the power my 6500D was. I set the gain with a volt meter, and then by ear, I was in disbelief. I had to keep turning it down to get rid of distortion. I thought I had missed a setting somehow. MTX used to under-rate their amps, but apparently that is no longer the case. I've been a die-hard MTX fan/use for well over 10 years. This is the first time I am going to return an MTX item. I've got my return label printed out, and my 6500D ready to drop off at the repair shop.

The earbuds are nice. I wanted to keep them, but they are not that nice for the price. So they go back as well, unfortunately.

Pros: Fast shipping from Crutchfield, Great customer support making returns very easy. Very easy to install.

Cons: Bogus power rating. Runs hot.

MTX Road Thunder RT500D

Written By l, Sumter SC on Tuesday, June 03, 2014

Crutchfield Customer Review (What's this?)

Very easy install, and configuration. Made the 12" Sub Boom!

Return to item MTX Road Thunder RT500D

Written By Porto_Glock, Greenville, SC on Friday, May 23, 2014

Crutchfield Customer Review (What's this?)

I purchased this item a couple of weeks now. I'm very pleased with. Great size easy to configure. And the most important part. The "Bass" is banging just like I wanted!!

Pros: Compact design, MTX quality just perfect boomin bass. Also the price is unbeatable. Not to mention free MTX earbuds...

Cons: NONE

great amp

Written By Anonymous, Las vegas on Sunday, May 18, 2014

Crutchfield Customer Review (What's this?)

Great amp sonds amazing plenty of power

Pros: Price size

Cons: None

great little amp

Written By Ironman, Wy on Thursday, December 19, 2013

Crutchfield Customer Review (What's this?)

Powers my MTX thunderform 10" single sub just right. Great match. The remote gain is really nice.

Pros: Remote gain control, price. Nice size.

Cons: None.

Hands-on research

What's in the box?

Download owner's manual

  • Mono-block amplifier
  • Two 30A ATO fuses (installed)
  • External Bass Control
  • 17' External Bass Control cable (RJ-25 plug on both ends)
  • Two 10' Speaker level input cables (each has an RCA connector on one end and tinned bare wire on the other)
  • 2.5mm Allen wrench
  • Instruction manual (English/ French/ Spanish/ German/ Italian/ Portuguese/ Dutch/ Russian/ Finnish/ Polish)

Product Research



CEA-2006 Compliant: CEA-2006 is a system of testing and measurement methods for mobile audio amplifiers. This voluntary standard advocates a uniform method for determining an amplifier's RMS power output and signal-to-noise ratio. The criteria for measuring power uses a DC input voltage of 14.4 volts and the RMS power output is measured with 1% or less Total Harmonic Distortion plus noise (THD+N). Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt. CEA-2006 allows consumers to compare car amplifiers and receivers on an equal basis. Measured under CEA-2006 conditions the MTX Road Thunder RT250D is rated at 250 watts RMS x 1 channel into a 2-ohm load and 150 watts RMS x 1 channel into a 4-ohm load, the signal to noise ratio is 75 dB.

Mono-Block Amplifier: The MTX Road Thunder RT250D is designed with specific features to power your subwoofer or subwoofers with a frequency range between 20 to 200 Hz. This amplifier is not designed to power a full-range speaker.

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 increase. This improves the amp's overall signal-to-noise ratio and eliminates interference generated by more common Class D amps.

Protection Circuits: The RT250D provides Thermal and Short-circuit protection.


Gain: The rotary gain control is continuously variable from 250 mV to 5 V.

Bass Boost: The amplifier's bass boost is adjustable from 0-12dB at 40Hz.

Sub-Sonic Filter: This amp features a 12dB/octave Sub-Sonic Filter, adjustable from 20 to 50 Hz. Ultra-low frequencies that cannot be reproduced by the subwoofer do not become sound but unnecessary oscillations, which affect sound by causing distortion. These frequencies also waste amplifier power and can cause damage to the speakers. Setting the Sub-Sonic Filter between 20 and 50 Hz removes the frequencies below the respective frequency to improve the performance of the speakers by eliminating harmful distortion.

Crossover: The RT250D features a 12 dB/octave crossover, continuously variable from 40 to 200 Hz to match the frequency response of your connected subwoofer(s). The crossover is always engaged (it cannot be bypassed).

Remote Bass Knob: A wired External Bass Control (EBC) is included with the MTX RT250D. The EBC connects to the amplifier using the supplied 17' RJ-25 cord, it's designed to mount under your vehicle's dash within arm's length so its easily accessible to the driver. The approximate dimensions are:

  • Width: 1-9/16" (2-5/8" including the mounting tabs)
  • Height: 3/4"
  • Depth: 1-1/2" (2" including the knob and wiring)


Power/Ground/Turn-On: The RT250D features set-screw terminals for Power, Ground and Remote turn-on. The Power and Ground terminals will accommodate up to 4 gauge wire (which MTX recommends), while the Remote turn-on lead will accept up to 10 gauge wire.

Line Level Input: MTX recommends using the RCA type inputs with a line-level signal when possible.

Speaker Level Input: The RT250D comes with two speaker level to RCA adapters, making it easier to add an amplifier to a factory radio or to an aftermarket receiver with no preamp outputs.

Speaker Connections: The amplifier is equipped with set-screw speaker terminals; they will accommodate up to 8 gauge wire.

EBC: The RJ-25 port (phone type connection) is for the included wired remote.

Fuse: The amplifier is equipped with one ATO type 30 amp fuse.


5 Year Warranty Terms: This product carries a 5-Year Prorated Warranty with the following terms:

  • Years 1-2: Products found to be defective in materials or workmanship during the first two years will be, at Mitek's option, repaired or replaced by Mitek at no charge. The warranty period does not renew, but continues on from the original date of purchase.
  • Years 3-5: The purchase price of an item which becomes defective after the first two years and prior to the end of the warranty period will be prorated and credited toward the purchase of a new MTX product. The amount of proration is determined by dividing the original purchase price by the number of months in the warranty period (60), then multiplying the result by the number of months remaining in the warranty period.

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.