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Kenwood KAC-6406

4-channel car amplifier — 40 watts RMS x 4

Item #: 113KAC6406

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1 Review | 1 question - 2 answers

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Reliable performer

Kenwood makes tough, rugged amplifiers that bring you superior sound quality along with reliable performance. Add the Kenwood Sport Series KAC-6406 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-6406 4-channel amp delivers 40 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. Switch the amp over to 2-channel mode, and you can get great performance from a set of components or a couple of subs with up to 130 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
  • 40 watts RMS x 4 at 4 ohms (60 watts x 4 at 2 ohms)
  • 130 watts RMS x 2 bridged at 4 ohms (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • switchable high-pass filter (80 Hz, 12 dB per octave) on front (A ch) channels
  • variable low-pass filter (50-200 Hz, 24 dB per octave) on rear (B ch) channels
  • Class AB design and MOSFET power supply
  • preamp and speaker-level inputs
  • signal sensing turn-on eliminates need for remote lead
  • requires 10-gauge power and ground leads — wiring and hardware not included with amplifier
  • fuse rating: 30A x 1
  • 13-1/4"W x 2-3/16"H x 7-15/16"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-6406 Reviews

Average Customer Review:

1 Review

Nice amp for the cash

Written by: M. Doskocil from Cols., OH on November 1, 2014

Crutchfield Customer Review (What's this?)

Decent enough amp. I always use the RCA inputs on car amps, so keep that in mind. Probably about as loud as they claim (40 watts x 4). With the input tuned in to at or about 11:30, this is a clean robust little amplifier. Driving 2 pair of RF 5.5" coaxials, and they sound great! With the XTC baffles and a high pass filter set to 150 Hz this little baby sounds nice & clean. I just find that speakers sound that much deeper,. & cleaner (again with that word) when using the foam baffles, so call me a Big Fan. What else can I say? Quite a bargain at $150. Wish they would have put a fan in her though. Oh well. What can you expect for less than $200? Nice bargain, worth the cash.

Pros: Sounds clean at proper (low) input settings. Drives speakers in the claimed range (40 watts a channel) and sounds great doing it. Easy to wire up.

Cons: No fan.

Hands-on research

What's in the box?

Download owner's manual

  • 4-Channel amplifier
  • 30 amp ATO fuse (installed)
  • 7" Speaker-level input harness
  • Four 3/4" 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-6406 is rated at 40 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 60 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 130 watts RMS x 2 channels. If you prefer, just half the amp can be bridged for three-channel operation (40 watts RMS x 2 channels + 130 watts RMS x 1 channel).

Cast Aluminum Heat Sink: The KAC-6406 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-6406 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 and B sections have independent crossovers:

  • A-Channels: high pass with a fixed 80 Hz crossover point; 12 dB/octave slope; can be turned on or off
  • B-Channels: low-pass with a continuously variable (50-200 Hz) crossover point; 24 dB/octave slope; can be turned on or off


Power Connections: The power and ground connections are 0.5" 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. Minimum 10 gauge wire is required for power and ground.

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 a 30-amp ATO blade-type fuse.

Our Product Research Team

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Customer Q&A

1 question already asked

Nope, remote is wireless [ dave  Oct 21, 2015 ]
The remote wire is required. How would the amp know when to turn on or off if you didn't use one? [ BRANDON  Oct 20, 2015 ]