Overview

by Crutchfield's

Upgrade your power for better sound

You'll get some serious MTX musical mojo when you put the MTX THUNDER75.4 4-channel amp in your car. This compact amp will drive each of your front and rear speakers with 75 watts RMS of detail-enhancing musical power. Install a nice set of speakers, and you'll hear sounds you've never heard before, even in your favorite songs. And this little bruiser will truly fit in places where amps don't usually go

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Upgrade your power for better sound

Versatility

You can also put this amp into 2-channel mode to drive two subwoofers with 200 watts RMS per channel. In 3-channel mode, you can run some nice components up front with two channels while running a sub off the third channel.

Advanced tone control

The crossover filters on the front and rear channels allow you to adjust the sound to your setup. The front channels use a variable high-pass filter to keep the bass away from your full-range speakers, so they play cleanly. The variable rear crossover can be set to high- or low-pass depending on whether you're running a subwoofer or full-range speakers on the rear amp channels. It also features a very wide range of crossover points, that'll be useful for tuning midrange and midbass speakers.

MTX THUNDER75.4 control panel

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Product highlights:

4-channel car amplifier
75 watts RMS x 4 at 4 ohms (100 watts RMS x 4 at 2 ohms)
200 watts RMS x 2 bridged at 4 ohms (4-ohm stable in bridged mode)
frequency response: 15-25,000 Hz
Class AB amp technology
variable high-pass filter on front channels (10-200 Hz, 12 dB/octave)
variable high- and low-pass filters on rear channels (50-750 Hz, 12 dB/octave)
preamp inputs
4-gauge power and ground leads and a 60-amp fuse recommended — wiring and hardware not included with amplifier
no onboard fuses — when installing multiple amps in a system, an additional 60-amp in-line fuse between the distribution block and the amplifier is recommended
12-5/8"W x 2-1/4"H x 6-5/16"D
warranty: 2 years
Our 60-day money-back guarantee
MFR # THUNDER75.4

What's in the box:

MTX THUNDER75.4 owner's manual

4-Channel amplifier
4mm Allen wrench
2mm Allen wrench
Four 1/2" Self-tapping screws
Owner's manual (English/ Spanish/ Portuguese/ French)

Featured review

This is a great amplifier. I have it in my KJ Jeep Liberty. It fits perfectly under the driver's side seat. Everyone who rides in my SUV is impressed with the power of this amp attached to Infinity component and 2-way speakers. I highly recommend it for the sound enthusiast.

Logan from Ogden, UT

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Customer Q&A

Can this amp be used in 2 channel mode to run a pair of 6 1/2 inch coaxial speakers or would that not work due to the f/r crossovers being different?

This amplifier can be bridged down to a 2 channel amp giving you 200 watts at the 4 ohm load.

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MTX THUNDER75.4 reviews

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58 reviews

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Details

Researched by Crutchfield's Mark G.

Features & specs

Performance
RMS Power Output (Watts x Channels)	75 x 4
Peak Power Output (Watts x Channels)	200 x 4
Power at 2 Ohms (Watts x Channels)	100 x 4
Bridged Power (Watts x Channels)	200 x 2
Minimum Impedance Bridged	4
Minimum Impedance Unbridged	2
Minimum Impedance	2
Best Frequency Response	15-25000 Hz
THD at Rated RMS Power	0.05%
Signal to Noise Ratio	78 dB
Input Voltage	14.4v
Features
Amplifier Class	AB
Low-Pass Crossover Frequency	50-750 Hz
Low-Pass Slope (dB/octave)	12 dB/octave
High-Pass Crossover Frequency	10-750 Hz
High-Pass Slope (dB/octave)	12 dB/octave
Bass Boost	No
Bass Boost Frequency	N/A
Fan Cooled	No
Fuse Rating	60
Speaker Level Inputs	No
Preamp Outputs	No
Width (inches)	12-5/8
Height (inches)	2-1/4
Depth (inches)	6-5/16
Parts Warranty	2 Years
Labor Warranty	2 Years

The MTX THUNDER75.4 replaces these items:

MTX TH90.4

Product Research

Features
Connections

Features

Overview: The MTX Thunder75.4 is a full range 4-channel amplifier. It has aluminum heatsinks to dissipate heat generated by the amplifier. The amp produces 75 watts RMS x 4 at 4Ω, 100 watts RMS x 4 at 2Ω, and 200 watts RMS x 2 bridged at 4Ω.

Gain: The amp's front and rear channel rotary gain controls are independent and continuously variable from 200mV to 5V to match the output of the source unit.

Protection Circuits: The Thunder75.4 provides protection against overheating, under voltage, and electrical short circuits.

Crossovers: The front and rear channels have independent built-in crossovers:

Front: high-pass; continuously variable from 10 Hz (full range) to 200 Hz
Rear: switchable between low-pass, full range, and high-pass; the crossover point (high-pass or low-pass) is continuously variable from 50 Hz to 750 Hz

Connections

Power Terminals: The Thunder75.4 features set screw terminals for power, ground and remote turn-on. The power and ground terminals will accommodate up to 4 AWG wire, while the remote turn-on terminal will accept up to 10 AWG wire. The set screws are loosened/tightened with the supplied Allen wrenches. MTX recommends the use of 4 AWG power and ground wires.

Note: The Amplifier is not equipped with an internal fuse. An external 60-amp fuse (not included) must be installed on the power wire. If the system has only this amp and a wiring kit is used that includes a fuse with a value other than 60-amps, the original should be replaced with a 60-amp fuse.

Speaker Connections: The amplifier is equipped with four pair of set screw terminal speaker outputs. Each terminal will accommodate up to 10 AWG bare wire and is loosened/tightened with the supplied Allen wrench.

The MTX THUNDER75.4 replaces these items

MTX TH90.4

TH Series 4-channel amplifier — 60 watts RMS X 4

180 watts RMS x 2 bridged output at 4 ohms
variable high-pass/low-pass crossovers (40-400 Hz at 12 dB/octave)
preamp and speaker-level inputs

Accessories

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Q&A

11 questions already asked

Can this amp be used in 2 channel mode to run a pair of 6 1/2 inch coaxial speakers or would that not work due to the f/r crossovers being different?

[ Anonymous Feb 05, 2023 ]

1 answer

This amplifier can be bridged down to a 2 channel amp giving you 200 watts at the 4 ohm load.

[ ARIELLE H Feb 06, 2023 ] Staff

Currently I have 4 mtx 6 1/2s (2 in the front doors 2 in the rear deck) and I also have mtx tweeters in the dash. Could I run the tweeters off of this amp, or maybe run this amp for the four 6 1/2s and get a smaller mono amp for the tweeters?

[ Daniel Nov 24, 2022 ]

1 answer

Whether or not we can run the tweeters off of this amplifier will depend on the model of MTX tweeters that you are using. For detailed assistance with this project, please reach out to our advisors via online chat or phone at 1-800-324-9695.

[ ZACHARY Nov 26, 2022 ] Staff

is the protect light a clipping light?

[ VINCENT BRYCE Mar 02, 2022 ]

1 answer

The Protect light does not indicate clipped sound; it indicates faults within the wiring. We offer amps that do have clipping indicators. I recommend contacting an advisor by calling 1-800-324-9695 for a personal recommendation

[ JASON Mar 05, 2022 ] Staff

(Why is amp getting so hot?

[ Stevie Sep 13, 2021 ]

1 answer

It could be your power and/or ground connections

[ GARY Sep 13, 2021 ]

how big a gauge speaker wire can I use with this amp, 12 gauge?

[ JEFF Aug 26, 2021 ]

2 answers

The MTX 75.4 can handle up to 10awg speaker wire.

[ JOHN Aug 29, 2021 ]

I personally ran 4, I wouldn't do less than 8, you don't want to start a fire in your vehicle

[ SARAH E Aug 27, 2021 ]

Looking at the pop-up when moving this to the cart, it recommends 4 gauge amp wire kits, but other amps with the same RMS wattage are recommending 8 gauge amp wire kits. Which one would be best?

[ Cary Jul 14, 2020 ]

2 answers

4 gauge would be best. The terminals on the amp are sized for 4 gauge so 8 gauge might fit kinda loose. Also this is a powerful amp for its size and the larger the wire the less heat it will create.

[ MIKE Jul 21, 2020 ]

Depending on how far from your battery you place the amplifier, 8 gauge will work fine. If you are a long distance (more than 12 feet or so) upgrading to 4 gauge would be safer and help your amp last longer and sound great.

[ Jesse Jul 21, 2020 ]

This amp state to use a 60 Amp fuse I have a wiring kit with anl 150 amp can I use that or should I get a 60 Amp fuse ?and which one you recommend ?to get Im installing 2 rear coatial speaker 75rms x4 and 2 front component speaker 100 rms X 4

[ IRVIN Jun 05, 2020 ]

4 answers

Get the 60 amp fuse

[ HOLLY Jun 06, 2020 ]

I would get the 60 amp. I always go with what the manufacturer recommends. If you use the 150 it could damage the amp or be a fire hazard to your car if something in the amp or wiring shorted out.

[ LARRY Jun 05, 2020 ]

You need to use the fuse that it calls out to keep your amp protected.

[ Jeremy Jun 05, 2020 ]

I would use a 60 amp fuse. 150 might not blow in time. As far as which one, whichever you like!

[ Edward Jun 05, 2020 ]

Will this amp with 4 in the front and 4 in the rear 6x9?

[ CHARLES Aug 06, 2019 ]

2 answers

This is dependent on your RMS rating of your 6x9s assuming that they are 4 ohms as most 6x9s are. Without more information on your speakers make and model , it would be hard to determine if this amplifier is capable of driving you speakers. I would suggest taking the RMS of this amplifier as listed at 2ohms per channel, and match your speakers to the amplifier. I.E: 100 WATTS PER CHANNEL @2 OHM FROM THE AMPLIFIER TO 50 WATTS RMS PER SPEAKER.

[ YVETTE Aug 19, 2019 ]

You would over load it with 8 speakers.

[ ROBERT LELAND Aug 19, 2019 ]

Is this amp strong enough for 2 mtx 7500 10" sub's ?

[ Gary Nov 23, 2018 ]

1 answer

Thanks for your question. For information on selecting the best amp for your subs I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They will be able to help determine the differences between the amp models and help you make the best choice for your system.

[ KRISTINA Dec 03, 2018 ] Staff

Will this amp power two 10" subwoofers if you bridge this to two channels?

[ MARK May 04, 2018 ]

2 answers

Technically yes but it would depend on the volumes you were expecting and the specifics of the sub's you are planning on using. Personally, I attempted to use it to power one RF 8" sub and two sets of Focal components in the front of the vehicle - i.e. 2 channels straight @ 75w and 2 channels bridged for the sub - and I was not happy with the performance. I ended up using this amp in a 2 channel bridged configuration to run my components and added a second amp for the sub. If I were you I would purchase a 500 watt or higher mono amp to run your subs. Subs only need 1 channel power. Hope this helps.

[ Nicholas May 15, 2018 ]

No it is designed to run your higher frequencies, such as dash and door speakers. It performs very well for the price.

[ Stephen A. May 14, 2018 ]

How does the points system work? Do o get money off with the points?

[ Cliff Nov 20, 2015 ]

1 answer

The Crutchfield Rewards program gives you 1 point for every dollar you spend + an additional 50 points just for creating a free Rewards account. Once you've earned 250 points or more, you can turn your points into a Rewards Gift Card that you can use toward future Crutchfield purchases. They're redeemable at a value of 2% cash back, so 250 points = $5 gift card, 500 = $10, 1,000 = $20 etc. etc. Here's a link to more info on our Rewards program: http://www.crutchfield.com/Support/rewards.aspx?

[ DAVID Nov 20, 2015 ] Staff

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