Kenwood KAC-8406

4-channel car amplifier — 70 watts RMS x 4 (New Stock)

Item #: 113KAC8406

In Stock

3 Reviews

Your price: $229.99 Earn up to 230 Rewards points

Add to Cart

+ Add to wishlist + Email me alerts for this product

View all associated offers

Reliable performer

Kenwood makes tough, rugged amplifiers that bring you superior sound quality along with reliable performance. Add the Kenwood Performance Series KAC-8406 amplifier to your system, and you'll hear all the tonal color, impact, and detail you've been missing, from the punch of the rhythm section to the shiver induced by your favorite singer's voice.

Versatile power

The KAC-8406 4-channel amp delivers 70 watts RMS per channel to your full-range speakers. This amp will bring new life to your factory speakers, but you'll really notice the difference when you pair it up with new aftermarket speakers or components. Switch the amp over to 2-channel mode, and you can get great performance from a set of high-power components or a couple of subs with up to 200 watts RMS per channel.

This versatile amp features separate frequency filters for the front and rear channels, along with speaker-level inputs and signal sensing turn-on, so you can put this amp to work in just about any kind of system. Aluminum cover plates protect the amp's connections and controls, giving your installation a neat, professional look.

Product Highlights:

  • 4-channel car amplifier
  • 70 watts RMS x 4 at 4 ohms (100 watts x 4 at 2 ohms)
  • 200 watts RMS x 2 bridged at 4 ohms (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • variable high- and low-pass filters (50-200 Hz, 12 dB per octave)
  • switchable bass boost (0, 18 dB at 40 Hz)
  • Class AB design and MOSFET power supply
  • speaker-level inputs with signal sensing turn-on
  • preamp inputs
  • fuse rating: 25A x 2
  • 8-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 13-3/16"W x 2-1/4"H x 7-5/8"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-8406 Reviews

Average Customer Review:

3 reviews
Review this product
Great Gear Giveaway

Submit a review and then enter to win a $350 rewards card


Review this product:

Thanks for taking the time to share your experiences about this product. Please be sure to focus your comments on the product itself. Read our Review Guidelines for more information.

Your email won't be visible. Please use the email address that is associated with your order.
(e.g., JohnD) Your review will be signed using the display name and location
(e.g., Charlottesville, VA)

Click on a star to rate the overall product on a scale of 1-5
1500 characters left
  Attach a YouTube Review
Crutchfield Video Review Guidelines
  • Only submit videos that you made or are authorized to use.
  • Do not submit videos that contain music, video or visuals that are copyrighted and belong to someone else.
  • Please see our Review Guidelines for more information.
500 characters left
500 characters left

Much better clarity and quality

Written By kjs42, New York on Saturday, January 24, 2015

Crutchfield Customer Review (What's this?)

I was trying to find some more bass from my factory receiver with upgraded CS Kickers. This added the quality and clarity that I was looking for. And enough bass without blowing out my windows. Much better alternative than the $1,000.00 subwoofer the local stereo shop wanted to sell me.

Pros: Easy to install pretty easy directions. Has both speaker level and RCA inputs, so if I decide in the future to upgrade my head unit I want need a different amp.

Cons: The size is a little bigger then I would like. Hard to find an out of the way place. Not many options in a Wrangler.

Great improvement

Written By Stuart, Coon Rapids, MN on Friday, July 25, 2014

Crutchfield Customer Review (What's this?)

Great improvement in sound quality and power. I had previously a Kenwood receiver and 1 pair of factory speakers and 1 pair of Kenwood speakers. The amp in the head unit didn't have the power needed to do the speakers justice and the factory amp was shot. Wired this all up and adjusted everything, I could swear I had subs in my car again. I only have 2 pre amp outs so the speaker level input let me keep 4 zone control.

I had an existing 8 guage power wires from when I used to have a sub, which is the recommend wire for this sub. the bare wire won't fit in the terminal, I had to find some connectors to make it fit.

Pros: Improved sound quality and power over stock system and aftermarket receiver. Easy adjustment. Both pre amp and speaker level inputs Separate filters for front and rear channels.

Cons: Wish it came with at least the connectors to attach the power wires, recommend guage wire didn't fit for me.

Well worth the price

Written By Sturds, Florida on Sunday, March 23, 2014

Crutchfield Customer Review (What's this?)

WOW does it sound great! I upgraded my Honda Ridgeline speakers to Polk DB6501 component speakers in front and rear the Polks sounded OK they had great Highs and OK mids even at full volume with stock Head Unit, but now they sound like a whole new system with beautiful sounds at all volumes, with the factory Head unit turned to max and adjusting the amp gain I can't hear any distortion even at max on the gain, speaker level inputs made installation a breeze just cut, splice, and rock out. Using a multimeter on the power cable it is pulling about ~400W when hitting loud bass and mids at max volume. Stock Head Unit had trouble overcoming wind noise with windows down now with volume at 60% even highway winds are no match.

Pros: Great clean sound no distortion, definitely recommend!

Cons: Not really a con, warm to the touch after ~1 hour at 80-90% max volume, cold to the touch during normal use. Bass boost proved useless in my setup, just made speakers sound terrible. (IF not using separate amp and sub it would be very helpful though)

Hands-on research

What's in the box?

Download owner's manual

  • 4-Channel amplifier
  • Two 25 amp ATO fuses (installed)
  • 2 Terminal covers (installed)
  • 7" Speaker-level input harness
  • 2.5mm Allen wrench
  • Four 5/8" Self-tapping screws
  • Instruction manual (English/ French/ Spanish)
  • Warranty information

Product Research



CEA-2006 Compliant: CEA-2006 is a system of testing and measurement 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 4Ω load, with 1% or less Total Harmonic Distortion plus noise (THD+N), and over a frequency range of 20 Hz to 20 kHz (for full range amplifiers). Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4Ω. CEA-2006 standards allow consumers to compare car amplifiers and receivers under the same conditions (apples to apples). Using CEA-2006 criteria, the Kenwood KAC-8406 is rated at 70 watts RMS x 4 channels with an 80 dBA signal to noise ratio. The signal to noise ratio at the rated power output (not CEA-2006 conditions) is 100 dB.

2-Ohm Stable: The amplifier can support a 2-ohm load in stereo; the 2-ohm power output is 100 watts RMS x 4 channels.

Bridgeable: Each half of the four-channel amplifier can be bridged into a 4-ohm mono load; the bridged output is 200 watts RMS x 2 channels. If you prefer, just half the amp can be bridged for three-channel operation (70 watts RMS x 2 channels + 200 watts RMS x 1 channel).

Cast Aluminum Heat Sink: The KAC-8406 utilizes a cast aluminum heat sink design to ensure the amplifier stays cool.

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

  • speaker wire short-circuits
  • speaker output contacts ground
  • unit malfunctions and DC is sent to speaker output
  • the amp overheats

Power Indicator: When the amplifier is turned on the Power indicator (on top of the amp) lights up. This indicator turns off with the amplifier, and will turn off if the amplifier goes into protect mode.

Auto Turn-on: When using a speaker level input, the amp will turn on automatically when it senses the input signal.


Gain: To accommodate the varying range of signal levels from today's factory and aftermarket radios, the KAC-8406 features an adjustable gain control; 0.2-5.0 volts line level (RCA) and 4.0-12.0 volts speaker level.

Crossover: The four-channel amp is separated into two halves, labeled A and B. The A channel and B channel crossovers have independent controls:

  • Mode: high pass, low pass, or off (full range)
  • Frequency: rotary dial; continuously variable from 50 Hz to 200 Hz

Bass Boost: The bass boost circuit provides an 18 dB signal boost centered at 40 Hz; the bass boost is manually turned on or off.


Power Connections: The power and ground connections are 0.55" wide screw terminals. The remote turn-on screw terminal is 0.35" wide. A Phillips-head or flat blade screw driver (not supplied) is required to tighten/loosen the terminals. Spade connectors are recommended. The manual lists a minimum of 10 gauge wire for power and ground, but given the 50 amp fuse value and the current consumption specification of 35 amps, we recommend an 8 gauge wiring kit.

Speaker Outputs: The four pair of speaker outputs are 0.35" wide screw terminals. A Phillips-head or flat blade screw driver (not supplied) is required to tighten/loosen the terminals. Spade connectors are also recommended for the speaker wires.

Line Level Input: The line input is two pair of stereo RCA jacks (A-channels and B-channels).

Speaker Level Input: A wiring harness is included for the speaker level input.

Fuse: The amplifier uses two 25-amp ATO blade-type 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.