Super-slim profile, big-time power

Kenwood's Excelon XR400-4 4-channel amplifier adds clarity and punch to your car's audio system, as it powers each of your front and rear speakers with 75 watts RMS. As your system changes, you can also use the XR400-4 in 2-channel mode to drive a couple of subs with up to 200 watts RMS each. The XR400-4 can fit in many different places in your car because of its incredibly low profile — it's under 1-1/2" tall.

Designed for optimum efficiency

Kenwood packed this amp with space-saving features. Class D technology reduces the size of the power supply, while the internal heatsink is tilted to reduce height without compromising the amp's cooling system. Recessed power and speaker wire terminals help to further reduce the amp's footprint, protect the connections, and give your installation a neat, professional look.

Controls for the best sound — bi-amp capable

You can contour the sound with high- and low-pass filters so your speakers play efficiently and sound their best. The front and rear channels have separate gain and filter controls so you can adjust for different types of speakers. The XR400-4 also gives you the ability to "biamp" your system, amplifying the tweeters and woofers separately for greater power and control over the sound.

Product Highlights:

  • 4-channel amplifier
  • 75 watts RMS x 4 at 4 ohms (100 watts RMS x 4 at 2 ohms)
  • 200 watts RMS x 2 bridged output at 4 ohms (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • variable high- and low-pass filters (50-200 Hz; 2.5K-10k Hz, 12 dB/octave)
  • Class-D amplifier design
  • frequency response: 20-20k Hz
  • preamp inputs
  • fuse rating: 30A x 2
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 8-11/16"W x 1-7/16"H x 8"D
  • warranty: 90 days
  • 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.

Hands-on research

What's in the box?

Download owner's manual

  • Refurbished 4-channel amplifier
  • Two 30-amp mini blade fuses (installed)
  • 4mm Allen wrench
  • 2.5mm Allen wrench
  • 2mm Allen wrench
  • Four 5/8" Self-tapping screws
  • Instruction manual (English/ French/ Spanish)
  • Warranty card

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 measuring 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 into a 4-ohm load, with 1% or less Total Harmonic Distortion plus noise (THD+N), and over a frequency range of 20 Hz to 20 kHz, when applicable. Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4 ohms. CEA-2006 allows consumers to compare car amplifiers and receivers on an equal basis. Using CEA-2006 criteria, the Kenwood XR400-4 is rated at 75 Watts RMS x 4 channels with a 76 dBA signal to noise ratio.

Specifications: The manual also lists these non CEA-2006 compliant specifications:

  • Power:
    • 2Ω: 100 watts x 4-channels (at 1 kHz, with no more than 1% THD, 14.4 volts)
    • Bridged: 200 watts x 2-channels (into 4Ω at 1 kHz, with no more than 1% THD, 14.4 volts)
  • Signal to Noise Ratio: 100 dB (at rated power)

Class D Amplifier Design: The amplifier design is Class D, which uses digital switching power supplies. The result is much higher efficiency (less heat generated) than Class AB.

4-Channel Amp: The front and rear sections of the amplifier (labeled A and B) have independent gain and crossover controls.

Crossovers: The front and rear crossovers can be independently set to high-pass, low-pass, or turned off (full range). The crossover points are continuously variable with a selectable range, from 50-200 Hz or 2.5-10 kHz and the slope is 12dB per octave.

Aluminum Heat Sink: The aluminum heat sink increases the amplifier's heat dissipation efficiency, increasing the life of the amplifier.


  • Input Selector: two position switch:
    • AB: separate inputs are supplied for the front and rear channels
    • A: the signal supplied to input A is fed to both front and rear outputs
  • Input Sensitivity: 200mV-5V; front and rear independently adjustable
  • Crossover: the front and rear channels have independent controls for these crossover functions:
    • Mode: high-pass, low-pass, or off (full range)
    • Frequency Range: low (50-200 Hz) or high (2.5-10 kHz)
    • Frequency: continuously variable; 50-200 Hz or 2.5-10 kHz, depending on the setting of the frequency range switch

Inputs and Outputs:

  • Signal Input: two pair of RCA preamp inputs; front and rear (labeled A and B)
  • Power: set screw terminal; accommodates bare wire up to 4-gauge
  • Ground: set screw terminal; accommodates bare wire up to 4-gauge
  • Remote Turn-on: set screw terminal; accommodates bare wire up to 10-gauge
  • Speaker Output: four pair of set screw terminals (left and right A channels and left and right B channels); accommodate bare wire up to 10-gauge
  • Fuses: two 30 amp mini blade fuses

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.

Kenwood Excelon XR400-4 Reviews

Average Customer Review:

6 reviews
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Great price great amp!!

Written By Mattdaddy82, Alamogordo,NM on Tuesday, August 19, 2014

Crutchfield Customer Review (What's this?)

For the price this amp is amazing .. I usually go with a jl audio for my 4 channel but this one had decent reviews so I gave it a shot, that and my deck is an excelon .. I have this amp pushing a type r 6.5 component set in front and a alpine type r 5.25 set in rear .. More than enough power for all and the design profile is amazing it's small enough to fit under the dash in some applications .. I put mine under my seat so I can tune it easily

Pros: Price, size , look

Cons: Wish there were a bit more tuning options

Nice amp

Written By Jeffrey812, Sarasota FL on Monday, August 04, 2014

Crutchfield Customer Review (What's this?)

It's a nice amp,clean power.The output watts are way over rated I am using the amp to power infinity kappa 6x8 speakers and i would say you would be lucky to get 50 watt RMS at 2 ohm.But that's plenty for me.

Pros: Small footprint,Nice clean natural power

Cons: None

Very Nice

Written By William T., Orland Park, IL on Monday, June 30, 2014

Installed in a 2012 Sonata Turbo to power four Kenwood KFC-X173's. Plenty of power with clean sound. Small footprint is very nice.

Pros: Clean power / small footprint

Cons: None

Nice for the price

Written By Negolien, Sacramento,CA on Wednesday, May 21, 2014

I purchased this as a refurb. The packaging was pretty bad to be honest. Not on par with the normal packaging I have received from Crutchfield. It seems the item was shipped back from Kenwood to Crutchfield in a box with no peanuts or wrapping of any kind thus the amp was slamming around inside a box about 2-3 inches larger than the amp all the way around. When it was shipped to me that box was stuffed into a much larger box filled with peanuts. Still slamming around inside the smaller box... Very poor Packing by the Shipping and receiving department.

The item itself was a great product by a great Company. I paired this to run a pair of Polk DB461's and a pair of Infinity Kappa 93.11i's with a KAC-8105D that runs my 2 12" MTX JH45's. Superb value in size and features. The ability to run one set of RCA's in to power two separate pairs of speakers yet be able to use the pass filters = awesome. you can run 4 pairs of speakers on a 6 output headunit which is a super value if you want to run kicker area component speakers, door speakers and a sub.

The amp itself worked fine for a refurb I have no issues and you can't beat it for the price. Both my amps are Kenwood's and they are great bang for the buck. I would not hesitate to recommend the product.

Pros: Size is awesome a very very compact amp perfect for the two sets of cab speakers.

Cons: A little pricay brand new but that's why I went for the refurb. Hey can't beat that price with a stick.

Kenwood Excelon XR400-4

Written By Shaunt317, Indianapolis on Monday, April 21, 2014

Crutchfield Customer Review (What's this?)

Great amp. It sounds amazing and has plenty of power.

Pros: Easy connections.

Excellent Product

Written By Tom L, Avon, CO on Wednesday, October 23, 2013

Crutchfield Customer Review (What's this?)

This amp lives up to the Kenwood reputation of producing clean, distortion-free sound. It's small profile makes for an easy install beneath the seats, and the adjustment options are plentiful and effective. I've tried other products, but I always come back to Kenwood.

Pros: Clean sound, ample power, small size and ample adjust-ability.

Cons: None