Want more power? Maybe you've got a component speaker system or a power-hungry sub, or maybe you just like to crank the volume a little bit louder than your neighbor. Whatever the reason, Kenwood amplifiers have got your power needs covered.

The KAC-8151D mono subwoofer amplifier uses its highly-efficient Class-D design to pump out big power from a small package — up to 500 watts RMS (at 1 ohm)! Kenwood builds in a variable low-pass crossover, adjustable subsonic filter, and selectable bass boost so this amp can adapt to any bass gig. The KAC-8151D also includes a remote bass boost control, so you can adjust the bump right from the driver's seat.

Details:
  • 200 watts x 1 at 4 ohms
  • 400 watts x 1 at 2 ohms
  • 500 watts x 1 at 1 ohm
  • 1-ohm load capability
  • requires 8-gauge power and ground leads — wiring and hardware not included with amplifier
  • 50-200 Hz low-pass crossover, 18 dB/octave
  • subsonic filter (off/15/ 25 Hz), 18 dB/octave
  • bass boost (off/6/9/12 dB at 90 Hz) with wired remote
  • speaker- and preamp-level inputs
  • preamp outputs
  • dimensions: 11-7/16"W x 2-5/16"H x 11-1/4"D
  • 1-year warranty
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Hands-on research

What's in the box?

Download owner's manual

  • Mono amplifier
  • Speaker level input harness
  • Rubber terminal cover
  • Remote bass controller
  • 20' Remote cable (with RJ-11 plugs on each end)
  • Remote controller dressing plate
  • Knob
  • Flat washer
  • Hex nut
  • 2 Self-tapping screws (3mm diameter x 12mm)
  • Double-stick tape
  • 4 Self-tapping screws (4mm diameter x 16mm)
  • Instruction Manual
  • Warranty card

Product Research

Features
Inputs and Outputs
Additional Specifications

Features

Class D Amplifier Design: The KAC-8151D is a Class D mono-block amplifier, which uses digital switching to amplify audio signals. This design results in high efficiency and less heat.

1-Ohm Stable: This amplifier is capable of handling a 1-ohm load. You can drive two 2-ohm speakers, or four 4-ohm speakers in parallel with this amp. There are two sets of speaker outputs that are wired internally in parallel, making it easier to connect multiple speakers.

Speaker Level Input: The amp comes with a 2-channel speaker level input harness. Once you to splice a pair of 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 a receiver with no preamp outputs. The maximum power output from the source receiver can be no more than 40 watts.

Line Level Output: The amplifier has a pair of gold-plated 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.

Ground Isolation Circuit: This circuit cancels noise from the input of the negative side of the RCA cable, preventing vehicle electrical noise from interfering with the music. The amp has a ground screw located near the line inputs for use with RCA cables with ground leads.

Low Pass Crossover: The KAC-8151D has a built-in 18 dB/octave low-pass crossover that is continuously variable from 50Hz to 200Hz.

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.

Selectable Bass Boost: A bass boost of +6dB, +9dB or +12dB at 90Hz can be controlled by the supplied Remote Bass Controller. The controller can be mounted at the front of the vehicle, and is connected to the amp by the supplied 20' control cable. If you do not choose to use the Remote Bass Controller, you can still switch on/off a 12dB bass boost on the amplifier itself. Dimensions of remote bass controller: W=1.813", H=1.184", D=2.453" (including knob).

Dynamic Expander: The amp features a Dynamic Expander circuit which increases the dynamic range when switched on. 

Quiet Turn-on: To protect the speakers from damaging "thumps", the KAC-8151D has a quiet turn-on circuit, which allows the amplifier to power up over a period of milliseconds instead of instantaneously.

Protection circuitry: The amplifier has the protection circuits and will shut itself down in case of the following events:

  • 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

Inputs and Outputs

Left Side of the Amplifier

  • GND: Philips-head screw for RCA signal ground
  • Line input jacks: gold plated RCA inputs
  • Line output jacks: gold plated RCA outputs
  • Remote: RJ-11 jack for supplied Remote Bass Controller cable
  • Speaker-level input: multi-pin input for use with included speaker level input harness

Right Side of the Amplifier

  • Fuse: 40 amp fuse
  • BATT (Power): gold plated screw terminal (0.55" wide)
  • GND (Ground): gold plated screw terminal (0.55" wide)
  • P.CON (remote turn-on): gold plated screw terminal (0.34" wide)
  • Speaker outputs: gold plated screw terminals (0.34" wide) for two speakers (Note: These are not stereo outputs, but mono outputs wired internally in parallel.)

Additional Specifications

Specifications: 

  • Rated power output at 2 ohms: 400 watts x 1 (100 Hz, 0.5% THD)
  • Rated power output at 1 ohm: 500 watts x 1 (100 Hz, 1.0% THD)
  • Max power output at 4 ohms: 1000 watts x 1
  • Input impedance: 10k ohms
  • Operating voltage: 14.4 V (11-16V allowable)
  • Current consumption (4 ohms, 10% THD): 31A

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