Kenwood made their reputation building car amplifiers that offer no-nonsense reliability and superior sound quality. The compact KAC-8104D mono amplifier features a rugged cast-aluminum chassis more than 30% smaller than its predecessor, yet it'll still punch out up to 500 watts RMS to your subwoofers without straining your car's electrical system.

A built-in low-pass filter adjusts amplifier output so you'll get the best sound possible from your subwoofer/box combo, while the subsonic filter eliminates inaudible, ultra-low bass that can detract from your sub's performance. You can dial in up to 18 dB of bass boost if you want to fatten up the sound.

The front-mounted controls allow you to tweak the sound easily, and convenient front-side connections make setup a snap. Signal sensing turn-on and speaker-level inputs allow these amps to hook up to factory radios that don't have preamp level outputs.

Product Highlights:

  • mono subwoofer amplifier
  • 300 watts RMS x 1 at 4 ohms (500 watts x 1 at 2 ohms)
  • CEA-2006 compliant
  • variable low-pass filter (50-200 Hz at 24 dB per octave)
  • bass boost (0-18 dB at 40 Hz )
  • subsonic filter (15/25 Hz, 18 dB/octave )
  • Class D design
  • speaker-level inputs with signal sensing turn-on
  • preamp-level inputs and outputs
  • fuse rating: 40A x 1
  • 8-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 11-1/16"W x 2-3/8"H x 9-7/8"D
  • warranty: 1 year
  • 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.

Kenwood KAC-8104D Reviews

Average Customer Review:

18 reviews
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Kenwood KAC-8104D

Written By Tim, Dallas, Tx on Monday, January 25, 2010

Crutchfield Customer Review (What's this?)

This amp is great! I have it running two 12's, and the connection setup made it a million times easier. I have the setup with one sub off of each output. The amp gets the job done just fine. I may be upgrading to the next step up just to juice my subs a little bit more. I purchased the amp as part of a bass package, which turned out great! Crutchfield knows how to pair them!

Good Amp For The Money

Written By William, Surry, VA on Monday, January 11, 2010

This amplifier is a GREAT buy for those who have 10" subs, or 12" subs with no more than 250 RMS EACH. I've owned it for just over a year now, and like it, it does a good job, but it does overheat. It's never hot to the touch, in fact, it's probably no more than 120* during the summer. I can hold my hand on it when it "overheats" until it plays again, and have no desire to pull it off. I have it hooked up to two Kenwood 12"s, which command 400 RMS each. So, yes, the subs are underpowered. I have the gain at maybe 60%, and if I play it to the point the subs distort slightly, it'll be good for about a minute, then shut off for ~ 10-15 seconds, then play again. It'll do this until you turn it down some. At normal listening level, it sounds great! I recommend it, but it's always best to get an amp that matches your subs. Money was tight at the time, so I did this. I kind of regret it, but don't plan on getting rid of the amp. It'll most likely go in my other vehicle sometime in the future.

Don't waste your time

Written By Str8Flush, Baltimore MD on Thursday, September 10, 2009

I purchased this item as factory reconditioned. I used it to power two JL
10" subs in my 32' power boat. The amp performed well, however, five
months later it stopped working. When I unmounted it I could hear
something loose inside the amp when it was shaken. I went back on line
and there were more "factory reconditioned" amps for sale. I had
purchased an extended warranty from Cruthfield and assumed that if I
needed to replace it they would send me another amp and I'd return the
old one. Mistake.....I would have to send it to some other entity and wait
for them to fix it and have no sound until that occured. I'll do what I should
have done the first time, buy the JL 1700 and he happy.

Compact,Powerful. Must Have!

Written By Brandon, Maine on Thursday, August 20, 2009

This thing is absolutely amazing. I have 2 Sony XS-L104P5B 10" subs in the dual bass slammer box. It drives those subs real good. They hit really hard. The shake my entire car. Pumps out 250RMS each to my subs with the gain, and the bass boost maxed out with ease. It hasn't over heated yet. Just warm to the touch. Its small and compact, all the terminals are on one side. Overall this amp is a must buy. Beats most those other amps and for the price...what are you waiting for?

clear bass and no problems

Written By Johnny, youngstown ohio on Monday, June 22, 2009

i got this amp powering my 2 rockford fosgate 12's and it thumps great you
can feel the bass on your back as your thumping. people say it overheats
but thats quite untrue becuase i play songs with heavy bass and no
overheating. I also drive around for long period of time and no overheating
so people dont know what there talking about becuase this amp is great. if
you want to get your subs thumping and heads a turning get this amp

Great amp

Written By Doug, Roseville, MN on Thursday, May 07, 2009

Crutchfield Customer Review (What's this?)

I bought this to replace the failed internal amp in my Infinity Basslink sub. It's only a 10" sub but I'm sure it would handle another one with no problem.

Kenwood KAC-8104D

Written By D'Angelo, Baltimore, MD on Monday, April 13, 2009

I use this amp to power my boston acoustics g5-1244 and i must say it does a wonderful job of it. I also have a kenwood excelon hu that has 4 volt preamp outputs. So there is no need to turn my settings all the way up. I just turn up the bass boost and I'm good to go. I normally don't turn the sub level on the hu past 5(out of 15) because i'm afraid i'll crack my back window. This amp can definitely power any entry-mid level sub out there. And a few high end subs.

Kenwood KAC-8104D

Written By Sam, Bremerton, WA on Tuesday, March 31, 2009

Have it powering two 12D4's sealed in the back of my 94' Firebird. Never had an overheating problem or any sort of problems with it whatsoever. It's only pushing 300 watts total to both subs they hit very hard, low, and clear. When I turn up my cd player all the way, it just gets ridiculously loud, while still being very clear.

Sounds awesome!

Written By Nathan, Twin Cities, MN on Saturday, February 07, 2009

I bought this to power a Kenwood W2511 (300wrms), and it sounds awesome. The one thing I had problems with were the "signal-sensing turn-on" speaker level inputs. They only worked when there was lots of bass, but then turned the amp off when the bass went down. I ended up buying a new HU with sub-preouts, and haven't had any other problems. Great amp for the price.


Written By John, Medina, MN on Wednesday, December 24, 2008

I bought this amp despite the fact that there were a lot of bad reviews out there about it over heating and I have it powering one JL 13tw5 and let me tell you this thing thumps my sub like no other. And I play songs with huge bass lines and this amp has yet to even get warm even though it thumps my sub to the point where my mirrors are worthless. Would highly reccomend but be sure to set the gain correctly...


Written By Nicholas, NJ on Thursday, December 11, 2008

After getting a decent kenwood head unit recently, I decided to give my 10in Alpine type-s' a present. I got this amp replacing a less superior bazooka ela500.1 amp that would overheat if pushed too hard, even with the level below center point! Anyway, this amp bumps, loud and clear with minimal heat. I haven't had it overheat yet and if I bump any higher i'll blow my subs, so this amp has more than enough power for them :) Thus, I am a happy camper.

Best monoblock ever

Written By Jacek, Little River SC on Tuesday, December 02, 2008

Crutchfield Customer Review (What's this?)

I have two 12's JL audio w1v2 4ohm subs. After figuring out the best way to wire the SVC subs to this beast, I decided to buy it. The amp is turned to the middle and beats the JL's to death.

kenwood always a good choice

Written By Jim, naples fl on Monday, November 24, 2008

Crutchfield Customer Review (What's this?)

been using kenwood products since the mid 1980's and never had a bad experience this amp rocks !!
the only bad thing is the bright anoying light on top that cant be turned off
just cover it with black tape

Decent Mono Amp for the Money

Written By tower, Houston, TX on Friday, November 21, 2008

Kenwood's latest mono, and a decent choice for pushing a single mid-level sub or two entry-level subs. All-in-all almost identical to Alpine's MRP-M500, with the same price point and power ratings (300W @ 4ohm, 500W @ 2ohm), and not 1ohm stable. Its pretty compact, but my favorite thing
about it would be the fact that all the connections are on one side, making for easier installation. None the less its not bullet-proof, it will shut down
on you if you push it too hard or wire your subs incorrectly. There are definitely better amps out there in the same price/power bracket.

power packed

Written By red dragon, las vegas on Wednesday, May 21, 2008

i own this amp,its pushing 1kicker solo 12L7 and beats it to death. youll never get a better amp at a better price.

excellent amp

Written By Skip, Birmingham AL on Wednesday, April 09, 2008

Great amp to push my Punch stage 3 RF 10" at 2 ohm, as it stated its not a bridgeable amp

Kenwood KAC-8104D

Written By David, Humnoke, AR on Tuesday, March 25, 2008

Awesome amp it really beats my two 10 inch kicker comp vts in a sealed box i would recomend this amp but i did have 1 problem it would turn itself off during the middle of any song but kenwood was great about getting it fixed but after that it really beats the 2 kickers. They beat so hard the box actually bounces in the air the seats have to hold it down. So buy this amp its great and at a great price for a 1000 watt amp.

Kenwood KAC-8104D

Written By jon, ATL ,GA on Wednesday, February 13, 2008

Please be aware this AMP isnt worth the price. I have it on 1 kicker cvr 12 4ohm and all the settings are all the way up. And it still isnt enough power too drive My kicker 12. I can forget about adding the second one. Please dont buy this amp If your Using Kicker ,JLaudio speakers. Even with ith bridged it still doesnt pound and I have My kicker in a sealed box.

Hands-on research

What's in the box?

Download owner's manual

  • Mono amplifier with one 40-amp fuses inserted into the chassis
  • Speaker-level input harness
  • 4 Self-tapping screws
  • Rubber terminal cover
  • Hex-key
  • Instruction Manual (English/French/Spanish)
  • Warranty Card

Product Research



CEA-2006 Compliant: CEA-2006 is a new 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 into a 4-ohm load, with 1% or less Total Harmonic Distortion (THD) plus noise, and at a frequency range of 20 Hz to 200 Hz 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. The Kenwood KAC-8104D under CEA-2006 regulations is rated at 300 Watts RMS x 1 channel with a 83dBA signal to noise ratio.

Mono-Power Amp Design: The Kenwood KAC-8104D is designed with specific features to power your subwoofers with a frequency range between 5-200 Hz. This amplifier is not designed to power a full-range speaker.

2-Ohm Stable: The Kenwood mono-amplifier is capable of handling load impedances down to 2-ohms. The amplifier is rated at 500 Watts RMS x 1 channel in 2 ohms at 100Hz with 0.8% THD.

Class D Amplifier Design: The KAC-8104D is a Class D mono-block amplifier, which uses digital switching to amplify audio signals. This design results in high efficiency and less heat.

MOS-FET Switching Power Supply: The amplifier utilizes a MOS-FET switching power supply providing thermal stability and efficient switching speeds guaranteeing performance and dependability.

Parallel Connection: The amplifier is equipped with two pairs of gold-plated speaker terminals for an easy parallel subwoofer connection.

Low-Pass Filter: The KAC-8104D has a built-in 24dB/octave low-pass filter that is continuously variable from 50Hz to 200Hz.

Bass Boost: The bass boost is adjustable from 0-18dB at 40Hz.

Infrasonic Filter: This amp features an 18dB/octave Infrasonic Filter. Ultra-low frequencies that cannot be reproduced by a subwoofer do not become sound but become unnecessary oscillations, which affect sound by causing distortion. These frequencies also waste amplifier power and can cause damage to speakers. Setting the Infrasonic filter switch to 15Hz or 25Hz cuts the frequencies below the respective frequency to improve the reproduction performance of the speakers by eliminating harmful distortion.

Line Level Inputs: The RCA type line-level inputs have a gain (Input Sensitivity) control. The Input Sensitivity control will accept an input signal of 200mV to 5.0 Volts.

Signal Sensing Speaker Level Input: The KAC-8104D comes with a speaker level input harness. This feature makes it easier to add an amplifier to a factory radio or to a receiver with no preamp outputs. You don't need to connect the remote turn-on wire when using the speaker-level input harness because the power of the amplifier is turned "On" and "Off" as the amp detects input signal from the unit's speaker level input.

Line Level Output: The amplifier has a set of line level outputs for feeding a full-range stereo signal to another amplifier. It is the same signal that is input through the line inputs. The amplifier's crossovers have no effect on the line level output signal.

Power Indicator: When the power is turned on to the amplifier, the Power indicator will light up. This indicator will turn off with the amplifier and will turn off if the amplifier goes into protect mode. The amplifier also features a Blue LED lamp on the top of the amplifier which illuminates when the amplifier is on.

Protection circuitry: The amplifier features protection circuits that will turn the amp off in case of the following events to protect the amplifier and your speakers:

  • Speaker output contacts ground
  • Speaker wire short-circuits
  • Unit malfunctions and DC is sent to speaker output
  • Internal temperature is too high
  • Loss of ground of head unit or amp


Front of the Amplifier: All of the amplifier's controls are found on the front of the amplifier.

  • Bass Boost Level: 0-18 dB
  • Low Pass Frequency: 50-200 Hz
  • Input Sensitivity: 200mV-5V
  • ISF Switch: 25Hz, 15Hz or off


Front of the Amplifier: All of the amplifier's connections are found on the front of the amp.

  • Fuse: One 40A fuse
  • Power: Gold-plate screw terminal (0.5625" wide)
  • Ground: Gold-plate screw terminal (0.5625" wide)
  • Remote Turn-on: Gold-plated screw terminal (0.3125" wide)
  • Speaker Outputs: Two pair of gold-plated screw terminals (0.3125" wide)
  • Line In: One pair of gold-plated RCA inputs
  • Line Out: One pair gold-plated RCA outputs
  • Speaker-level Input: Multi-pin input for use with included speaker level input harness

Note: The amplifier features a brushed aluminum top cover which needs to be removed to access the Power, Ground, Turn-on, and Speaker terminals. The cover is held in place by two small hex-head screws which are removed using the supplied hex-key. Once all connection are made, the top cover should be re-installed.

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.