Alpine MRX-F65

4-channel car amplifier — 110 watts RMS x 4

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  • Alpine MRX-F65


  • Alpine MRX-F65

  • Alpine MRX-F65

  • Alpine MRX-F65

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Item #: 500MRXF65

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Original price $349.99
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Our take on the Alpine MRX-F65

by Buck Pomerantz

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.

Alpine Authorized Online Dealer

Digital technology that sounds perfect

Alpine's X-Power MRX-F65 4-channel amplifier uses the latest in amp technology to play your music loud and clean without taking up much space. And this compact amp employs some of the same circuitry developed for Alpine's top-of-the-line PDX digital amps so it'll bring exceptional sound to your ride.

Alpine's X-Power MRX-F65 4-channel amplifier

Massive power for high-level systems

The MRX-F65 puts out 110 watts RMS per channel, so you'll have plenty of clean power to fill your listening space with music. You can even use it in 2-channel mode to drive a pair of subs with 320 watts each. Onboard frequency filters let you tailor the output to fit your setup, and a bass boost on the rear channels helps to fatten up the sound.

Looks cool too

A power management system optimizes the amp's performance and keeps the music playing, even when you're pushing it hot and hard for a long time. Speaker-level inputs with an automatic turn-on feature simplify system hook-up.

MRX-F65 control panel

Read more


  • 4-channel car amplifier
  • 110 watts RMS x 4 at 4 ohms (160 watts RMS x 4 at 2 ohms)
  • 320 watts RMS x 2 in bridged mode (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • variable high- and low-pass filters (50-400 Hz, 12 dB/octave)
  • variable bass boost (0-12 dB at 50 Hz) on rear channels
  • preamp and speaker-level inputs
  • Class-D amplifier design
  • MOSFET power and output stages
  • fuse rating: 30A x 2
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 10-11/16"W x 2-5/16"H x 9-1/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and Specs
RMS Power Output (Watts x Channels) 110 x 4
Peak Power Output (Watts x Channels) ---
Power at 2 Ohms (Watts x Channels) 160 x 4
Bridged Power (Watts x Channels) 320 x 2
Minimum Impedance Bridged 4
Minimum Impedance Unbridged 2
Best Frequency Response 5-45k Hz
THD at Rated RMS Power 1%
Signal to Noise Ratio 87 dB
Input Voltage 14.4v
Amplifier Class D
Low-Pass Crossover Frequency 50-400 Hz
Low-Pass Slope (dB/octave) 12 dB/oct
High-Pass Crossover Frequency 50-400 Hz
High-Pass Slope (dB/octave) 12 dB/oct
Bass Boost 0-12 dB
Bass Boost Frequency 50 Hz
Fan Cooled No
Fuse Rating 60
Speaker Level Inputs Harness
Preamp Outputs No
Width (inches) 10-11/16
Height (inches) 2-5/16
Depth (inches) 9-1/16
Parts Warranty 1 Year
Labor Warranty 1 Year
Product Research
What's in the box?

Download owner's manual

  • 4-Channel amplifier with two 30A ATO fuses installed
  • Left plastic terminal cover
  • Right plastic terminal cover
  • 4 Terminal cover screws (M3 x 10mm)
  • 4 Self-tapping screws (M4 x 20mm)
  • 2.5mm Allen wrench
  • 7" Speaker-level input harness
  • Owner's Manual (Eng/ Fren/ Span)
  • Warranty sheet
  • Online registration card
  • Alpine Verification Certificate

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 open the box, verify contents, 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.



MRX Amplifier Design: Class-D amplifiers boast higher efficiency, produce less heat, and draw less current than traditional Class-AB amps. The MRX series benefits from the technology trickledown from Alpine's more expensive PDX amps, including Direct FET final outputs, thermal management processor, 6-Layer Glass Epoxy PC Board; combining to create a high-end sound quality without the bulky heat sinks required by most amps in this power class.

STAR Topology: Alpine's unique STAR (Signal Transit for Accurate Response) Circuit PCB design provides a single common ground for all amp sub-blocks, preventing ground interference and minimizing internal noise.

Power Management Processor: The multi-stage Power Management Processor continuously monitors component temperatures throughout the amplifier and decreases power output if anything gets too hot. When playing music under heavy loads for long periods, the circuit automatically reduces power output slightly at first, and then further in a second stage if necessary. This two stage approach provides an interruption free listening experience.

CEA 2006 Compliant: The MRX-F65's power ratings are measured according to the Consumer Electronics Association CEA-2006 standards. These standards allow you to accurately compare the rated power output of all CEA 2006-compliant amplifiers, even different brands. Manufacturers who adhere to the standards can display the CEA 2006 logo on their products and packaging. The power output is measured from 20 Hz to 20 kHz using a 14.4 volt power supply with no more than 0.01% THD+N:

  • 4-ohms: 110 watts RMS x 4
  • 2-ohms: 160 watts RMS x 4
  • 4-ohm bridged: 320 watts RMS x 2

Signal-to-Noise: When measured under CEA-2006 conditions (reference 1 watt into a 4-ohm load) the signal to noise ratio is 87 dBA. Measured at the rated power output S/N is 106 dB.

Verification Certificate: The amplifier comes with a certificate that lists the RMS power output measured from that specific amplifier. It also lists the model number, serial number, test date, and the test conditions (voltage and impedance).

Auto Turn On: When using the speaker level inputs the X-Power amplifiers automatically turn on when voltage is detected on the signal inputs, making them an easy factory system upgrade.

Low Output Impedance: With low output impedance, the MRX-F65 outputs tightly controlled bass, with a damping Factor rated at greater than 500.

LED: The top panel LED power indicator glows blue when the amplifier is turned on.


Gain: The MRX-F65's gain can be independently set for the front and rear channels. The line-level input gain setting is continuously variable from 200 mV to 4.0V; the speaker-level input gain setting is continuously variable from 500 mV to 10.0V.

Crossovers: The amplifier has independent built-in crossovers for the front and rear channels. They can be set to low-pass or high-pass operation, or off via a three-way switch. The crossover frequency is continuously variable from 50 to 400 Hz and the slope is 12 dB/oct.

Bass EQ: Bass boost for the rear channels is variable from 0 to +12 dB and centered at 50 Hz.


Power/Ground/Remote: The MRX-F65 features set-screw terminals for the Power, Ground and Remote Turn-on inputs. The Power and Ground terminals will accommodate up to 4 gauge wire, while the Remote Turn-on terminal will accept up to 8 gauge wire. Based on the fuse rating and power output, 4 gauge power and ground wires are recommended.

Speaker Output: The speaker output terminals are screw terminals which will accept up to 8 gauge wire.

Line Inputs: Line level RCA is the preferred input connection. There are two pairs of RCA line-level inputs. No line output is provided.

Speaker Level Input: Use the included speaker level input harnesses if the connected radio has no preamp outputs.

Fuses: The amp is protected by two chassis-mounted 30-amp ATO fuses.

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Alpine MRX-F65 Reviews

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4 out of 5

Alpine MRX-F65

Written By bcarn, phx az on Wednesday, February 26, 2014
Crutchfield Customer Review (What's this?)
Solid 4 channel amp in tight compact package.
Higher than rated power. Stays cool even when pushed.
Pricey but worth it. Mounting feet aren't the strongest. (Bumped one during install and it snapped off. Super glue to the rescue!)
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5 out of 5


Written By Honda8282, Billings, MT on Monday, February 10, 2014
Crutchfield Customer Review (What's this?)
Sounds really crisp more then enough power I need, very compact smaller then I thought. Customer service very helpful.
Should last along time
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5 out of 5

Sonic joy!

Written By MarkS, Sellersville, PA on Saturday, September 14, 2013
Crutchfield Customer Review (What's this?)
It's an Alpine - what else can I say? Install is in a 2006 Jeep Liberty Limited (formerly with the OEM Infinity HU and speakers). New HU = Kenwood KVT-516 (from Crutchfield), front speakers = Infinity Kappa 60.11cs (2 ohm) and rear speakers = Kicker Compvt65 (2 ohm) compact subwoofers. This was the final piece to the slow upgrade of the OEM system over the last 2 years as various speakers began to fail. Now I understand the true meaning of "power". The system has come alive! With the 2 ohm speakers I am more than likely at about 180w (RMS). Still dialing in the final adjustments and EQ. Amp fit under rear seat on driver side (slide in sideways, turn, fits perfectly - only needed to Velcro - no side-to-side movement or front-to-back). Exactly what I needed to take this system to the next level. It's like having a new car. Bought the Amp from scratch and dent to save some $$ - did not disappoint - sealed box with all parts and install manual - same warranty. Stellar.
Stellar amp and easy install and accessible adjustments for HP, LP, bass boost, gain. Fits the 2006 Jeep Liberty under rear seat driver's side perfectly
None - other than why did I wait so long to purchase?
2 out of 2 people found this helpful
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5 out of 5

Awesome amp!!!

Written By Anonymous, NJ on Wednesday, September 04, 2013
Crutchfield Customer Review (What's this?)
I love alpine products! Bought this amp knowing it would be great after owning 3 of their other amps. Its doing 116x4 at 4 ohms and its driving 4 8" mid range woofers and the MRX-F65 is slammin.
1 out of 1 people found this helpful
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5 out of 5

Good Amplifier for 110 Watt RMS Alpine Speakers

Written By Vinny, DC on Sunday, May 26, 2013
Crutchfield Customer Review (What's this?)
Okayyyy, so check this out. I just got this amplifier installed today. Well, I started freaking out because as I increased the gain on my radio, everything was all jacked up and distorted. Little did I know, you have to mess around with the "Gain" settings on the amplifier after installation until the distortion goes away. Then, you got yourself a beautiful amp.
Doesn't overheat, small, loud
1 out of 1 people found this helpful
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5 out of 5

Great amp for 2006 Ford Freestar

Written By DavidF, MD on Thursday, March 21, 2013
Very happy with this amp.

Fit it under front passenger seat (manual). I made a mounting plate from some scrap I had laying around, bolted the plate to the seat's central frame bar at floor where seat electrical plugs mount. Just unsnapped the plugs from the bar and left them loose above the amp so they can move as seat is adjusted. Grounded to base of virtical pillar between front/side doors. Used 4AWG power kit: StreetWires ZeroNoise 5 ZN5K-04, heavy speaker wires: StreetWires UCT14, and line-level cables: StreetWires Zero Noise 5 Stereo Patch Cables 4-channel (11.5'). Turned sideways, heat sink/case is pretty safe/rugged in case back-seat feet, etc. get on it.

Combined with new head unit Pioneer DEH-X9500BHS (6x 4V lines) and 4x Alpine SPR-68 speakers (6x8, 110WRMS). Sounds good as is, but awaiting spring 2013 birthday for a Kicker PES10C sealed enclosure/powered sub.

Amp has a nice set of connections, options, adjustments, but I just needed basic 4-way line in, 4 speakers out. Decent bare wire terminal connections; I think set screw hex wrench was included.
Good quality, nice match up for 100W speakers, nice set of connections & adjustments, fairly small size for power (class D).
7 out of 7 people found this helpful
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