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Alpine X-A90M

X-Series mono subwoofer amplifier — 900 watts RMS at 2 ohms

4 Reviews | 1 question - 2 answers

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Our take on the Alpine X-A90M

Alpine's X-Series X-A90M subwoofer amplifier will sharpen the focus of your music's bass image — it'll sound like the bass and kick drum are playing inside your car. This mono amp puts out up to 900 watts RMS of sub-pounding power, making it a perfect match for an Alpine X-Series 10" or 12" subwoofer. Speaker-level inputs allow you to add this amp to almost any system, even one with a factory radio.

Alpine Authorized Online Dealer

Mono powerhouse

Alpine's X-Series X-A90M subwoofer amplifier will sharpen the focus of your music's bass image — it'll sound like the bass and kick drum are playing inside your car. This mono amp puts out up to 900 watts RMS of sub-pounding power, making it a perfect match for an Alpine X-Series 10" or 12" subwoofer. Speaker-level inputs allow you to add this amp to almost any system, even one with a factory radio.

High-tech Class-D innards

Beefy internal components and the cleverly designed Thermal Flow chassis help the amp produce its power efficiently, with little excess heat or stress to your vehicle's electrical system. Alpine designed this amp to exert tight control over subwoofer cones, so you'll experience realistic bass. A special comparator circuit corrects the output using the original input signal, minimizing phase issues for precise, high-fidelity sound. 

Hidden controls and plug-in connectors

The amp's tuning controls sit protected under a removable top panel. Nifty speaker and power wire plugs make it easy to install or remove the amp, while ensuring a tight connection. Gold-plated RCA inputs, outputs, and power connections resist corrosion and signal degradation. For a creative touch, you can paint the amp's trim panels to match or contrast with your vehicle's interior decor. An optional wired remote lets you tweak your sub's volume from the front seat.

Product Highlights:

  • mono subwoofer amplifier
  • 600 watts RMS x 1 at 4 ohms (900 watts RMS x 1 at 2 ohms)
  • CEA-2006 compliant
  • Class-D amplifier technology
  • frequency response: (+0/-1 dB) 10 to 300 Hz
  • variable low-pass filter (50-400 Hz, 24 dB/octave)
  • switchable subsonic filter (off, 15 Hz, 30 HZ)
  • optional RUX-KNOB.2 wired remote level control
  • preamp and speaker-level inputs
  • RCA preamp outputs
  • quick-connect speaker connector fits wire up to 8-gauge
  • fuse rating: 20A x 4
  • wiring and hardware not included with amplifier
    • 4-gauge power and ground wire recommended
  • 10"W x 2"H x 8"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's in the Box:

  • Mono amplifier
  • Two 35A ATO fuses (installed)
  • Terminal Cover Left
  • Terminal Cover Right
  • Terminal Cover Front
  • Battery connector plug
  • 2 Speaker connector plugs
  • Logo Plate (self-adhesive)
  • 4 Self-tapping screws (Length 3/4")
  • 2mm Allen wrench
  • 4mm Allen wrench
  • Owner's Manual
  • Alpine Verification Certificate
  • Limited Warranty
  • To Customers sheet
  • Thank you note

Featured Video

So far it sounds great, can not test it fully until my sub break in. Will up date soon

Tony, Plainfield, IL


Alpine X-A90M Reviews

Average Customer Review(s):

(4 Reviews)

The Most Bang for Your Buck!

Edward from Evansville, IN on 2/13/2019

Crutchfield Customer Review (What's this?)

Literally the most bang for the buck in the lineup. This amp doesn't break a sweat! My application is powering 2 sealed enclosure 12" subs with a combined impedance of 2 ohms and a low sensitivity of 83, and at normal listening levels I have much, much, much more than a fair amount of volume headroom. I have it in Jeep wrangler so am looking forward to taking the top off, going out on a remote camping trip with friends, playing some tunes with serious thumping bass. Will definitely keep the bears and wildlife away. This is a bad boy!

Pros: Powerful, solid, clean bass. Small profile. Very cost efficient, yet sounds as though it should be in a higher price class.

Cons: None. Though, thinking to purchase a capacitor to keep this beast juiced at ultra high volume.

So far very clean bass

Tony from Plainfield, IL on 12/7/2018

Crutchfield Customer Review (What's this?)

So far it sounds great, can not test it fully until my sub break in. Will up date soon

Pros: Small amp and powerful worth the price

Cons: None


David from .Insker Mi on 11/1/2018

Awesome equipment, ALPINE never ceases to amaze me.Great job ALPINE.The only equipment I use.....DAVE



Good Amp.

Carlos from Seguin TX on 3/27/2018

Crutchfield Customer Review (What's this?)

An amazing Alpine product. I have it pushing two old alpine type S 12s and it works them out to the max, they sound really good for being 8 yrs. old. I'm waiting for this amp to blow them out so I can replace them with type R.

Pros: Wire connectors make installation easy. 900 watt at 2 ohms with xover and filter.

Cons: A little pricy but can't beat the quality.


Hands-on research

Product Research



X-Series Amplifiers: Alpine's X-Series amplifiers are designed for high performance, low distortion, power, and reliability. With Alpine ID (Image Defined), this Class-D amplifier delivers the imaging and sound stage depth that has been missing in most car audio systems. Alpine's proprietary circuit design provides the cleanest possible signal path, plus a dual-feedback loop, to meet and exceed the audio standard for High Resolution playback (full range amps only). The solid cast aluminum heat sink keeps the amplifier cool, even at peak power levels. Each X-Series amplifier comes with its own Alpine Verification Certificate, showing the tested power output at 2Ω at 14.4 DC voltage.

Channel Design: The Alpine X-A90M is a mono amplifier, dedicated to driving subwoofers. It is stable down to 2Ω.

CTA 2006 Compliant: The X-A90M's power ratings are measured according to the strict standards dictated by the Consumer Technology Association (CTA). These standards allow you to accurately compare the rated power output of all CTA 2006-compliant amplifiers, even if they come from different brands. Manufacturers who adhere to the standards can display the CEA 2006 logo on their products and packaging. The CTA 2006 power output specs for the X-A90M are:

  • 4Ω: 600 watts RMS x 1 @ 14.4 Volts
  • 2Ω: 900 watts RMS x 1 @ 14.4 Volts

Frequency Response: The Alpine X-A90M has the following frequency response:

  • +0/-3 dB (1W into 4Ω): 8 Hz - 400 Hz
  • +0/-1 dB (1W into 4Ω): 10 Hz - 300 Hz

Terminal Covers: The X-Series amps each have removable silver terminal covers on the front and sides that improve the appearance of the amplifier. Once you have made all of the connections and confirmed proper operation, you can attach the terminal covers by snapping them into place.

Logo Badge: The top of the amplifier features four bright white LEDs that glow when the unit is powered on. A self-adhesive Alpine Logo Badge is provided for placement over the LEDs so that the logo glows blue when lit. You can choose the orientation of the logo depending upon the installation.


Hidden Controls: The amplifier's controls are hidden behind a removable top panel. The panel can be lifted by removing two hexagon screws with the supplied 2mm Allen wrench.

Gain Control: The X-A90M's rotary gain control lets you set the amplifier's gain according to the level of the incoming signal. The amp will accept low level signals from 0.1V to 4.0V, or high level signals from 0.5V to 10V. An input level switch on the front panel should be set to match the type of input signal used.

Crossover: The Alpine X-A90M offers a Low-Pass Filter with a variable cutoff frequency of 50Hz to 400Hz. The Subsonic Filter cuts off super-low frequencies that the subwoofer cannot cleanly reproduce. The cutoff frequency is variable from 8Hz to 40Hz. Both filters have a slope of 24dB per octave.

Bass EQ: The amplifier has a variable Bass EQ (or Bass Boost) circuit that raises the level of the amplifier output at 50Hz from 0dB to +12dB.

Optional Remote Bass Control: The amplifier has an RJ-25 modular jack for adding the optional RUX-KNOB.2 Remote Bass Level Control for controlling the amp output remotely. The RUX-KNOB.2 has a 20dB range of linear adjustment.


Terminal Layout: For wiring convenience, all of the inputs and outputs on the amplifier are on one side.

Quick Connect Plugs: The X-Series amplifier uses quick connect plugs to attach your system's speaker wires and power cables to the amp for a simple, error-free installation. The quick connect plugs have set screw terminals that can be tightened/loosened by the supplied hex wrenches (2mm or 4mm). The power, ground, and remote turn-on connections are made to a single quick connect plug. The power and ground terminals will accept up to 4 AWG (recommended) wire, while the remote terminal will accept up to 12 AWG. The speaker output plug has terminals for two speakers which allows you to connect two subwoofers or a single dual voice coil sub. The speaker terminals will accept up to 8 AWG wire.

Input: The Alpine X-A90M is equipped with one pair of RCA jacks for connecting low-level or high-level input signals. If connecting the source unit's speaker wire to the input jacks, you can use a Speaker-to-RCA adapter or splice an RCA plug onto the speaker wire. When using a high-level input signal, it may not be necessary to connect a remote turn-on lead because of the amplifier's remote sensing function.

Pre-Output: A second pair of RCA jacks provides a line level output for sending a signal to a second subwoofer amplifier. The output matches the input signal, and is not affected by the amplifier's crossover.

Fuses: The Alpine X-A90M is equipped with three 30-amp ATO fuses. A 90A external fuse should be placed on the +12V power wire within 18" of the battery.

Our Product Research Team

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Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

good reviews [ Jorge  Aug 30, 2017 ]

1 question already asked

2 - 2 ohm subs wired in parallel = 1 ohm impedance total at the amp. [ Edward  Feb 08, 2019 ]
This amp is not rated for 1-ohm operation. 2-ohm is the lowest listed stable impedance. The power rating there is 900 watts RMS x 1 at 2 ohms. [ Jeff  Feb 08, 2019 ]  Staff