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Kenwood Excelon KAC-X520

125W x 2 Car Amplifier

Item # 113KACX520

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Our take on the Kenwood Excelon KAC-X520

The variable color indicator on a Kenwood Excelon amplifier cycles through seven bright colors or remains locked onto your favorite for constant illumination. The indicator starts flashing if your amp goes into protect mode, so you'll know what's wrong at a glance — just by the color of the flash!

The variable color indicator on a Kenwood Excelon amplifier cycles through seven bright colors or remains locked onto your favorite for constant illumination. The indicator starts flashing if your amp goes into protect mode, so you'll know what's wrong at a glance — just by the color of the flash!

But beneath the intensely cool exterior of these amplifiers is where the real action takes place. For inside the rugged cover lurks a MOSFET-fueled beast, armed with efficient power supplies and large secondary capacitors that send power tearing through your system!

Kenwood has incorporated a sophisticated Bass Management System into Excelon amps — BMS applies a 12 decibel bass boost (variable from 40-100 Hz), allowing you to tune low end output with a stunning degree of accuracy. Connected to a compatible Kenwood Excelon receiver (with BMS controls and an external amp lead), you gain even more control with a choice of 6, 12, or 18 dB of bass boost from the comfort of the driver's seat! A built-in infrasonic filter enhances performance by eliminating power-robbing inaudible frequencies.

If your speakers or subs are up to the job, the KAC-X520 amp will make them sing. You'll enjoy clean Kenwood Excelon power, thanks MOSFET output devices, superior construction, and ultra-effective built-in crossovers (variable 50-200 Hz: 18 dB per octave low-pass, 12 dB per octave high-pass).

  • 125 watts RMS x 2 at 4 ohms
  • 250 watts RMS x 2 at 2 ohms
  • 500 watts RMS x 1 at 4 ohms in bridged mode
  • stereo or bridged mono output
  • Tri-way capable (Tri-Way crossover required)
  • infrasonic filter (15 Hz, 24 dB/octave)
  • 50-200 Hz crossovers: 12 dB/octave high-pass, 18 dB/octave low-pass
  • 12 dB bass boost variable from 40-100 Hz (expandable to 6/12/18 dB when connected to a Kenwood Excelon receiver equipped with BMS controls)
  • Bass Management System
  • preamp outputs
  • fan cooling
  • speaker short, low battery, thermal overload, and DC protection
  • variable color indicator
  • gold-plated terminals
  • requires 4-gauge power and ground leads — wiring and hardware not included with amplifier
  • 2" wide detachable terminal covers
  • 17-9/16"W x 2-5/16"H x 12-1/2"L
  • 2-year warranty

What's in the Box:

  • Black and silver amplifier
  • 2 Black plastic terminal covers
  • 4 Metal brackets (for mounting terminal covers)
  • Two 30-amp fuses (inserted into amp)
  • Four 18mm Self-tapping screws
  • Four 8mm Self-tapping screws
  • 4 Hex-head screws (M3 x 8mm)
  • One 2.5mm Allen wrench
  • Instruction manual
  • Warranty card
  • On-line product registration card (with free CD sampler offer)

Hands-on research

Product Research


Inputs and Outputs

More Specifications


Bass Management System (B.M.S.): This feature allows precise tailoring of bass frequencies, either remotely, with a compatible Kenwood eXcelon head unit, or manually, when used with a head unit without B.M.S. controls. When connected to a Kenwood eXcelon head unit (1999 or later models with an "External Control" wire attached), the B.M.S. controls can select 0dB, 6dB, 12dB of bass boost. The bass boost center frequency is variable between 40 Hz and 100 Hz. Newer head units with B.M.S. control can also select 18dB of bass boost and "frequency offset." The frequency offset control can switch between "Normal" (as set by the variable control) or "Low" (20-30% lower). The manual B.M.S. setting provides a 12dB of bass boost at the frequency selected.

Variable-Color Indicator: The status indicator on the top of the amplifier is a variable-color LED that lights in one of 7 selectable colors or constantly changing colors to tell you the amplifier's operating status. Under normal operation, the LED glows constantly. The LED will blink in a certain color based on the amp's status or if the amp has malfunctioned and has gone into protection mode. The blinking color codes include:

  • Blue: B.M.S. is activated.
  • Yellow: The input power is less than 11 Volts.
  • Purple: A DC signal is being sent to the speaker output.
  • Red: The unit is overheating.
  • Green: A speaker cable is shorted or making contact with vehicle ground.

Internal Crossover: The internal crossover is selectable for high-pass, full range, or low-pass operation, and is variable from 50 Hz to 200 Hz. The slope of the high-pass filter is 12dB/octave and the low-pass filter is 18dB/octave.

Infrasonic Filter: This amplifier features an infrasonic filter, which can cut off inaudible frequencies. Extremely low frequencies can be stressful to an amplifier or loudspeakers, and can cause distortion in the audible frequencies. The infrasonic filter can be set to OFF or ON, with a slope of 24dB/octave. When on, frequencies below 15 Hz are cut off, resulting in increased amplifier efficiency and better audible sound.

Fan Cooled: This amplifier has an internal cooling fan. There are air inlets on the top of the amp; air exhaust outlets are on the ends of the amp.

Terminal Covers: The amplifier comes with two black plastic terminal covers designed to be mounted on each end of the amp to hide the wires and give it a cleaner look. Mounting hardware is included.


Top of Amplifier (under removable cover):

  • Input Sensitivity Control: Rotary control that allows you to adjust the output level of the amplifier.
  • B.M.S. Frequency Control: Rotary control that allows you to set the center frequency of the bass boost when the B.M.S. switch is set to "+12dB" or "Remote"
  • V-Color Button Control: Selects the "ON" color for the LED indicator. Each time the button is pressed it selects one of 7 fixed colors or the variable color indicator.
  • LPF Frequency Control: Rotary control that allows you to adjust the crossover frequency of the low-pass filter.
  • HPF Frequency Control: Rotary control that allows you to adjust the crossover frequency of the high-pass filter.

Right Side of Amplifier:

  • Infrasonic Switch: This switch allows you to turn on or off the Infrasonic filter.
  • B.M.S. Switch: This switch allows you to set B.M.S. operation to Remote, Off, or +12dB.
  • Filter Switch: This switch allows you to select HPF (High Pass filter), Off, or LPF (Low Pass filter)
  • Operation Switch: This switch allows you to select Stereo or Mono operation. Note: When the amplifier is being used in the bridged mode, the mono operation should be selected. During mono operation, only the left channel input signal is amplified. There is no amplification of the right channel input.

Inputs and Outputs

Right Side of Amplifier:

  • Line In: one pair of gold-plated RCA jacks
  • Line Out: one pair of gold-plated RCA jacks
  • Ground: screw for use with RCA patch cables that have ground wires
  • External Amp Control: spring clip for use with compatible Kenwood head units with B.M.S. controls.

Left Side of Amplifier:

  • Fuses: two 30 amp fuses are inserted.
  • Battery: gold-plated screw terminal (width: 0.562")
  • Ground: gold-plated screw terminal (width: 0.562")
  • Power Control: gold-plated screw terminal (width: 0.35")
  • Speaker Outputs: gold-plated screw terminals for left and right channels (width: 0.35")

More Specifications

Maximum Output Power: 500 watts x 2 at 4 ohms; 1000 watts x 1 at 4 ohms bridged

Rated Power at 12 volts:

  • 90 watts x 2 (4 ohms, 20Hz-20kHz, 0.05% THD)
  • 170 watts x 2 (2 ohms, 1 kHz, 0.5% THD)
  • 340 watts x 1 (4 ohms bridged, 1 kHz, 0.5% THD)

Dimensions Without Terminal Covers:

  • Width: 14.625"
  • Height: 2.302"
  • Depth: 12.5"

Our Product Research Team

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