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Kenwood KAC-8405

4-channel car amplifier — 60 watts RMS x 4 (New Stock)

20 Reviews

Item # 113KAC8405

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Our take on the Kenwood KAC-8405

Kenwood Performance Series car amplifiers offer long-term reliability and superior sound quality in a compact, no-nonsense package. The KAC-8405 4-channel amp delivers 60 watts RMS to each of your front and rear speakers, or you can drive a couple of subs with 180 watts RMS each in 2-channel mode. A rugged cast-aluminum heatsink combines with two cooling fans to keep this amp running at optimal temperatures, even when you're pushing your system hard.

Kenwood Performance Series car amplifiers offer long-term reliability and superior sound quality in a compact, no-nonsense package. The KAC-8405 4-channel amp delivers 60 watts RMS to each of your front and rear speakers, or you can drive a couple of subs with 180 watts RMS each in 2-channel mode. A rugged cast-aluminum heatsink combines with two cooling fans to keep this amp running at optimal temperatures, even when you're pushing your system hard.

Built-in high- and low-pass filters adjust the output so you'll get the best sound possible from your system. You can dial in up to 18 dB of bass boost to fatten up the sound.

An aluminum cover plate covers and protects the amp's controls and connections, giving your installation a professional look. Speaker-level inputs and signal sensing turn-on allow these amps to hook up to factory radios without preamp outputs.

Product Highlights:

  • 4-channel car amplifier
  • 60 watts RMS x 4 at 4 ohms (90 watts x 4 at 2 ohms)
  • 180 watts RMS x 2 bridged output at 4 ohms (4 ohm stable in bridged mode)
  • 2-, 3-, and 4-channel operation
  • CEA-2006 compliant
  • variable high- and low-pass filters (50-200 Hz, 12 dB per octave)
  • variable bass boost (0-18 dB at 40 Hz)
  • dual cooling fans
  • MOSFET power supply
  • speaker-level inputs with signal sensing turn-on
  • preamp inputs
  • fuse rating: 30A x 2
  • 8-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 11"W x 2-3/8"H x 9-1/2"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's in the Box:

  • 4-Channel amplifier (with two 30A ATO fuses inserted in chassis)
  • 8" Speaker-level input harness
  • 4 Self-tapping screws (4mm diameter x 16mm)
  • Allen wrench
  • Instruction Manual (Eng/Fre/Spa)
  • Warranty card

Kenwood KAC-8405 Reviews

Average Customer Review(s):

(20 Reviews)

First amp

Tdhawkiz from Iowa on 8/17/2014

Crutchfield Customer Review (What's this?)

Installed amp to my stock 09 Ford F-150 regular cab to give it a "kick". I am powering four Kicker 6X8 speakers on the front portion (A) of this amp and it sounds great. I am still waiting on my 10" kicker sub. I will bridge the back (B) to push 130 watts. Overall I am pleased with this amp so far. Doesn't run hot. Gave it a 4 star because I'm sure there are better, but the price was right.

Pros: Speaker Level inputs was a feature I wanted to make installation easier for me. Cooling fans are a nice feature and I don't hear any background noise from them. Price was right.

Cons: Didn't fit under my seat. Not a deal breaker though.

There are better...

Brock247 from Chandler, AZ on 3/13/2014

There are better amps for the same price. The active crossovers are fine for powering small subs, mid bass, and midrange, but tweeters will require a passive or external high pass filter. The THD is fairly high (1%) compared to similarly priced amps on the market. The dials and switches collect dirt and dust easily, and the case is prone to scratching. The protection circuitry saved me numerous times. The amp works fine for a basic setup, but it lacks the features/quality needed for future upgrades. I would buy from a company that specializes in building more feature-filled amps.

Pros: Reserved appearance Dual fans Reliable

Cons: High THD Gets dirty easily Lower end filters only

Great Sound for your buck.

Manninse from Texas on 2/4/2014

Crutchfield Customer Review (What's this?)

I purchased a set of Polk Audio component speakers for front and rear. Of course with the existing Kenwood head unit, not enough RMS power to push. Once I installed the KAC 8405, this amp brought the Polk Audio's to life. This amp has very good frequency and gain adjustments to meet your vehicle ambiance levels. Very stable at 2 ohm bridged. Overall, this is a perfect amp if your needing that extra power with a new set of upgraded door speakers and or subwoofers.

Pros: Great overall amp to run your front and rear speakers.

Cons: Not all that powerful when using high output component speakers.

Kenwood KAC-8405

Anonymous from Jax, FL on 1/31/2014

Crutchfield Customer Review (What's this?)

I recently purchased a Kenwood KAC-8405 amp. The short version is it sounds awesome! I put it in 3 channel mode to power a pair of 6x9's and a single subwoofer. The power output is amazing. The Technical Support was terrific when I had a question about how to adjust the input to raise the volume up in my scenario.

Pros: Solid amp, nice power and sound. Has all the inputs I needed, easy to tweak for optimum peformance.


Kenwood KAC-8405

rod from Ga on 1/1/2014

Crutchfield Customer Review (What's this?)

sounds great

Pros: Fits good under the passenger seat of a 02 Toyota Sequoia


Kenwood KAC-8405

Nightrunner from Carolina Beach, NC on 11/13/2013

sounds real nice w/ the new system


Cons: sucks w stock systems

good amp!

Markie T from maryland on 9/11/2013

Crutchfield Customer Review (What's this?)

Did it exactly what I needed it to do!!



Nice amp

rocuno from Florence, Az on 4/9/2013

Crutchfield Customer Review (What's this?)

Have this amp running my highs and mids(Polk Audio) does a awesome job. Barely have them gains turned up. Nice that is has built in fans. Reasonable price





Crutchfield Customer Review (What's this?)

After hooking it up where another amp was removed, the amp was not working. Power & ground were good, but the amp was clipping and not loud at all. I tested it with a different input source to eliminate the radio. Had to send it back for replacement on day 1. CRUTCHFIELD is always good to help get things going as quick as possible. I love KENWOOD, but this one was a dud.

Pros: Small size. All connections on one side.

Cons: Power connections are bunched too close together and are too small.

KAC 8405

Jay G from Clementon NJ on 3/12/2012

This was the final piece in my factory system overhaul. I've replaced all factory audio components in my 2003 Kia Sorento including all the speaker wires. I have this amp powering Focal Access 165 A1's 6-3/4 components up front(unfortunately no longer carried by Crutchfield) & Focal Access 165 CA1's in the rear. There is no comparison when comparing the SQ when running the Focals off the HU(Kenwood Excelon x994) compared to powering them with this excellent amp. This amp woke up my Focals and made them sing. I have the gains set at about 3/4 and my speakers play so loud & clear that my ears surrender before the speakers distort. Anyone that tells you that you don't need an amp when powering quality speakers with a quality head unit is doing you a disservice. The amp has brought out detail & clarity in my music that I was missing before. I listen to a wide variety of music from classic rock to rap and all points in between & it all sounds incredible. The amp stays cool enough to abuse for long periods of time at very high volumes. The transformation of my 2003 Sorento's audio system is complete & everything with the exception of the speaker wires & an amp wiring kit came from Crutchfield.(I did get 1 free from Crutchfield when I bought my Infinity Basslink) Cruthfield products, customer service, & support is top notch. You can find some products a little cheaper on the web, but when you factor in everything, Crutchfield is the best & I'm a customer for life.

Pros: Fits in tight spaces(under the drivers seat) Built in cooling fans keep it running w/o overheating Ease of installation Quality Kenwood product. Good price.

Cons: 60 Watts RMS so if you need more power this amp isn't for you.


TODD Z from WISCONSIN on 2/1/2012

Crutchfield Customer Review (What's this?)




Nice Amp

Kj3000 from Arvonia Va on 1/30/2012

Crutchfield Customer Review (What's this?)

This amplifier is very quiet and runs very cool brings out the sound of my 5 1/4 and 6X9 speakers.


Cons: none

Kenwood KAC-8405

Ryan from Chino, CA on 1/26/2012

Crutchfield Customer Review (What's this?)

Pleanty of power. cant beat the price



Nice amp for the money

Brian from Evansville, IN on 8/1/2011

Crutchfield Customer Review (What's this?)

I purchased this amp with a recommendation from Crutchfield. I was looking for an amp and speaker system for my PT Cruiser. While this amp won't blow the windows out, it paired very nicely with a set of Kenwood 3-way 6x8's and Polk Audio Component speakers. The amp delivers enough power to have a very clean sound without over driving the system.



Better than expected

Ralph from Pikesville, MD on 7/6/2011

Crutchfield Customer Review (What's this?)

I bought this amp to replace a factory amp in my car. The power this amp provides is perfect. The highs are more brilliant and the overall balance to my system is incredible. Kenwood never fails to impress and produce. If you are looking for a solid amp with great performance, you won't go wrong if you pick this one.



Great amp

Fliptech from Cidra, PR on 5/31/2011

This amp exeded my expectations. I have always installed Rockford or Mtx amps on my cars but I bought this Kenwood because of the signal turn on through the speaker wire adapter, and the built in crossover, both worked great. The amp is small but it packes alot of power, and for a factory upgrade that does not involve touching the head unit (2006 accord) its perfect. I was a bit sketchy at first concidering that I was not running a remote cable to turn on the amp but it works great. The only down side is that my sound ordance speakers are now over powered, but reducing the power fixed the problem.



Kenwood KAC-8405

BARRY from CHESAPEAKE , VA on 5/9/2011

Crutchfield Customer Review (What's this?)

KENWOOD never fails to produce great products. This amp is compact with cooling fans and can fit in small locations. I mounted this amp under the back seat of 01 dakota quad cab. It works great - installation was tedius, but fully instructed.



I can't hear you?

Opus from Arizona on 12/27/2010

I installed this amp in a 2 door 2010 Tundra to power Infinity 630's and used the second channel, bridged, to power a 8" Infinity sub woofer. It installed cleanly under the front seat with plenty of clearance. The foot print of this amp is almost equal to a 8x10 sheet of paper. Instructions and set up was a breeze. I used a 4 awg wiring kit instead of the recommended 8 awg, needed to grind a little off of the sides of the amp wiring kit terminals to get it to fit into the amps screw slots, no big deal. At really low/no volume you can hear the cooling fans running, barely. The cross over filters could use better markings to accurately set them. You have to "guess" where 90 Hz is, due to the size of the slot for the screw driver. I error on the high side and used the Kenwood KDC x794 receiver cross over feature to complete the sub woofer set up. I started with the gain's set to 4 to match the receiver inputs, broke in the new speakers then starting increasing gain "1/2" unit at a time. Currently the gain is set to 1, with the receiver volume set to three quarters the sound is c-l-e-a-n but the loudness will cause you to turn it down. I know the Crutchfield customer service rep said this amp was under- powered for the Infinity speakers but... If you're looking to put together a 2.1 system in your vehicle or need 4 channel or high powered 2 channel bridged amp in a small package I would highly recommend this one.



Clean and Powerful

Mike J. from North, NJ on 10/17/2010

Crutchfield Customer Review (What's this?)

Installed this in my '07 Cobalt. This bad boy powers a set of old kenwood ie series 6x9's rear deck, kenwood ie series 5 1/4's in a custom rear quarter panel box I made, and a set of kenwood 6 1/2 components in the front.The reciever is an old kenwood exceleron x589. Has no prob. powering 6 separate speakers without any distortion and has a very clean sound.My 6x9's almost overpower my sub with bass that I never even knew they could get. I make extensive use I the HPF for the front's and rear quarter panels. Has all the filters you need, the power you need, and the sound you crave. Cannot go wrong with this amp. (BTW-Fronts and Rear Quarters are wired in a series@8 ohms.) Amp is 2 - 8 ohms per channel.




S.Craig06 from Cleveland, Ohio on 8/11/2010

Crutchfield Customer Review (What's this?)

This amp was suggested to me by Crutchfields knowledgable staff. For my application, I have eight speakers including two subs. I am powering my Inifinity 6 x 9 three way rear deck speakers, and Infinity 6 1/2" front door speakers. This amp coupled with the Infinity speakers will cause hearing loss. The rear 6 x 9's are technically slightly under powered, but WOW! I cranked up the gain all the way without distortion. You cannot go wrong with a Kenwood amp, and it is priced right for the quality and performance you receive. Has all the setting. Now my speakers produce good clean sound at HIGH volumes. It sounds just as good outside the car with all the doors closed. I believe this was a good buy for my application. I received this amp and installed it about three weeks ago, so there is much more to test, but overall I am satisfied, just wish they gave more output for the money.




Hands-on research

Product Research



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

CEA 2006 Compliant: The KAC-8405's power ratings are measured according to the strict standards dictated by the Consumer Electronics Association (CEA). These standards allow you to accurately compare the rated power output of all CEA 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.

Amplifier Rating: The Kenwood KAC-8405 Four-Channel amplifier is bridgeable (4-ohm), as well as 2-ohm stable in stereo.

  • Four-Channel (CEA 2006 Compliant): 60 watts x 4 channel RMS @ 4 ohms (20 Hz-20 kHz, 1% THD)
  • Four-Channel (2-ohm): 90 watts x 4 channel RMS (1 kHz, 0.08% THD)
  • Bridged (4-ohm): 180 watts x 2 channel RMS (1 kHz, 0.08% THD)
  • Peak Power: 180 watts x 4 channel (720 watts total max power)

Cast Aluminum Heat Sink: The Kenwood KAC8405 utilizes a cast aluminum heat sink design to ensure that the amplifier stays at its optimal temperature.

Fan Cooled: There are two fans and two vents located on the back side of the amplifier to help dissipate heat and ensure cool, reliable operation. Make sure not to block these vents or fans when you install the amplifier.

Protection circuitry: The amplifier features protection circuits that will turn the amp off in case of the following events:

  • Speaker output contacts ground
  • Speaker wire short-circuits
  • Unit malfunctions and DC is sent to speaker output

Aluminum Cover Plate: The amplifier's controls and connections are hidden under a removable extruded aluminum cover plate. The cover plate provides a professional looking installing while helping to protect the amplifier's connections and control settings. The cover is held in place by two hex head screws. An allen-wrench is supplied to remove the cover.

Blue/Red Illumination: The Kenwood Four-Channel amplifier features a blue and red LED illumination when the amplifier is turned on. When the power is turned on to the amplifier, the Power indicator will light up red. 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.

Signal-sensing Turn-On Circuitry: When the speaker-level input is used, it is not necessary to connect the power control wire (turn-on lead). The amplifier senses the signal from the speaker-level input and turns the amplifier power on automatically. Shortly after no signal is detected, the amplifier will automatically shut itself off.


Stereo/Mono Operation: You can independently switch Amplifier's front and rear channels from Stereo to Mono operation. When switched to Mono, the signal from the left channel inputs are only used.

Gain: To accommodate the varying range of signal levels coming from today's factory and aftermarket radios, the Kenwood KAC-8405 features an adjustable, independent gain control (0.2-5.0V) for the front and rear channels. This means that no matter what kind of radio is connected to this amplifier, the appropriate gain control adjustment can be made to ensure loud, clear, distortion-free music.

Crossovers: The KAC-8404 has built-in high pass and low pass crossovers. The high pass crossover's slope is 12 dB/octave and is continuously variable from 50Hz to 200Hz and can be controlled independently for the front and rear channels. The low pass crossover's slope is also 12 dB/octave and continuously variable from 50Hz to 200Hz and can be controlled independently for the front and rear channels. The amplifier can also be operated at full-range simultaneously for both the front and rear channels.

Bass Boost: A fixed bass boost of 18dB at 40Hz can be engaged for the rear-channels only. There is no bass boost for the front channels.


Power Connections: The power, ground, and remote turn-on connections are 0.3125" wide screw terminals that will accommodate up to 8-gauge wire. A Phillips-head or flat blade screw driver (not supplied) is required to tighten/loosen the terminals. Spade connectors are recommended for the power, ground, and remote wires.

Speaker Outputs: The Kenwood KAC-8405 is equipped with four pair of speaker terminals. All eight speaker terminals are 0.3125" wide  screw terminals and will accommodate up to 8-gauge wire. A Phillips-head or flat blade screw driver (not supplied) is required to tighten/loosen the terminals. Spade connectors are recommended for the speaker wires.

Note: The speaker output terminals can be used in 4-channel mode or bridged to 2-channels.

Line Level Input: The four-channel amplifier is equipped with two pair of gold-plated RCA line level inputs.

Speaker Level Input: The KAC-8405 comes with a four channel speaker level input harness. Once you splice the speaker wires from the receiver to the harness, you have plug-in convenience to the amplifier. This feature makes it easier to add an amplifier to a factory radio or to a receiver with no preamp outputs. The maximum power output from the source receiver can be no more than 40 watts.

Fuses: The KAC-8405 is equipped with two 30 amp ATC 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.