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MTX JackHammer JH805

5-channel car amplifier — 37.5 watts x 4 at 4 ohms + 500 watts x 1 at 2 ohms

10 Reviews

Item # 236JH805

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Our take on the MTX JackHammer JH805

The JackHammer Series by MTX offers just what its name implies — aggressive styling with plenty of hard-hitting power, so your system will look great and sound even better. The chrome detailing and powder-coated steel chassis with vented bumper guards provide exceptional durability, while the MTX logo lets people know you're packing serious power.

The JackHammer Series by MTX offers just what its name implies — aggressive styling with plenty of hard-hitting power, so your system will look great and sound even better. The chrome detailing and powder-coated steel chassis with vented bumper guards provide exceptional durability, while the MTX logo lets people know you're packing serious power.

The JH805 5-channel amplifier can power your entire system, delivering 37.5 watts RMS at 4 ohms to your front and rear speakers, plus up to 500 watts RMS to a subwoofer. Patented MTX technologies process and amplify your signal without wasting energy and creating harmful levels of heat.

Active Fan Cooling speeds up the internal fan as you turn your volume up, so more cool air reaches the inner workings as power demands increase. Variable filters help you match the signal output to your speakers, and a bass boost lets you control the "boom" in your sound.

What's in the Box:

  • 5-Channel amplifier with three 30A ATO fuses inserted into chassis
  • Bass knob
  • 16.5' Bass knob cable with RJ-11 connectors on each end
  • Four 24" Speaker level to RCA adapters (each have on RCA connector on one end and bare tinned wire on other end)
  • 2 Plastic jack stands
  • 2 Screws
  • Hex-key
  • MTX Warranty Statement/Wiring diagram
  • Amplifier Performance Certificate

Product Highlights:

  • 5-channel car amplifier
  • 37.5 watts RMS x 4 at 4 ohms + 250 watts RMS x 1 at 4 ohms
  • 75 watts RMS x 4 at 2 ohms + 500 watts RMS x 1 at 2 ohms
  • 150 watts RMS x 2 bridged at 4 ohms + 250 watts RMS x 1 at 4 ohms (500 watts RMS x 1 at 2 ohms)
  • frequency response: 20-200 Hz
  • variable front high pass filter (40-5,000 Hz, 12 db/octave)
  • variable rear high-pass (40-8,000 Hz, 12 dB/octave) and low-pass filter (40-5,000 Hz, 12 dB/octave)
  • variable subsonic filter (40-200 Hz, 12 db/octave)
  • bass boost (12 dB at 40 Hz)
  • Active Fan Cooling with automatic variable fan speed
  • Smart Engage turns on amp when signal arrives through the speaker-level inputs
  • CEA-2006 compliant
  • preamp and speaker-level inputs
  • fuse rating: 30A x 3
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 17-3/16"W x 2-3/8"H x 9-1/4"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

MTX JackHammer JH805 Reviews

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Product Research



CEA-2006 Compliant: CEA-2006 is a new system of testing and measurement methods for mobile audio amplifiers. This voluntary standard advocates a uniform method for determining 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 4-ohm load, with 1% or less Total Harmonic Distortion (THD) plus noise, and at a frequency range of 20 Hz to 20,000 Hz when applicable. Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4 ohms. CEA-2006 allows consumers to compare car amplifiers and receivers on an equal basis. The MTX Jack Hammer JH805 under CEA-2006 regulations is rated at 37.5 Watts RMS x 4 channels with a 75dBA signal to noise ratio + 250 Watts RMX x 1 channel with a 70dBA signal to noise ratio.

5-Channel Amplifier: The MTX Jack Hammer JH805 is a 5-channel amplifier designed to power your front and rear full-range speakers as well as your subwoofer(s). The JH805 can be configured for 5-way or 3-way operation.

2-Ohm Stable: The MTX 5-channel amplifier is capable of handling load impedances down to 2-ohms. The amplifier is rated at 75 Watts RMS x 4 channels + 500 Watts RMS x 1 channel in 2 ohms with 1% THD. 

Bridgeable: The MTX JH805's Front (1/2) and Rear channels (3/4) can be bridged down to two channels to output 150 Watts x 2-channels at 4 ohm.

AB/Class D Amplifier Design: The Jack Hammer JH805 features an AB class amplifier for its front and rear channels and a Class D amplifier for it subwoofer channel.

  • Pure N-Channel Mosfet Class A/B Design: The Jack Hammer's front and rear channel amplifier utilizes Pure N-Channel Mosfet technology for more linear speaker control, enhanced signal-to-noise ratio and more power. This design lets the audio signal travel through fewer parts making the output stage of the amplifier more efficient and giving you more usable power from the amp.
  • Class-D Design: The JH805's subwoofer channel is powered by a Class D mono-block amplifier, which uses digital switching to amplify audio signals. This design results in high efficiency and less heat.

Active Fan Cooling: Rather than weighing the amplifier down with heavy aluminum heat sinks, the Jack Hammer amplifier is cooled using a variable speed internal fan. The increasing output of the amplifier engages the fan to automatically increase its speed allowing more cool air to enter the amplifier. This keeps the amplifier performing at its peak level longer and prevents the amplifier from going into thermal shutdown due to overheating. The fan will automatically slow down when the amplifier's output is decreased.

Protection Circuits: The JH805 provides Thermal and Overload protection with LED indicators.

Stackable: You can stack up to three Jack Hammer amplifier on top of one another using the supplied "JackStands".


Crossovers: The Jack Hammer JH805 is equipped with various crossovers for all 5-channels.

  • Front Channel Crossovers: The Front channels (1/2) feature a variable 12dB/octave high-pass crossover which can be set between 40 and 8,000Hz. This crossover can be turned off for full-range operation.
  • Rear Channel Crossovers: The Rear channels (2/3) feature variable 12dB/octave high-pass and low-pass crossover settings. The high-pass crossover can be set between 40Hz and 8kHz, while the low-pass crossover can be set between 40Hz and 5kHz. There is also and Band-Pass setting for midrange or midbass speakers. In addition the Rear channels can be run at full-range.
  • Subwoofer Channel Crossovers: The Subwoofer channel features a variable 24dB/octave low-pass crossover which can be set between 40 and 200Hz.

Bass Boost: The bass boost is adjustable from 0-12dB at 40Hz.

Sub-Sonic Filter: This amp features an adjustable 20 to 50Hz, 12dB/octave Sub-Sonic 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 Sub-Sonic Filter between 20Hz to 50Hz cuts the frequencies below the respective frequency to improve the reproduction performance of the speakers by eliminating harmful distortion.

Remote Bass Knob: The MTX JH805 comes supplied with a wired remote bass knob which allows you to adjust the bass output of the amplifier's subwoofer channel. The bass knob is designed to be mounted underneath your vehicle's dash within arm's length so its easily accessible to the driver. The bass knob connects to the amplifier using the supplied 16.5' RJ-11 cord. The wired remote bass knob measures 2.655" wide x 0.755" tall x 1.955" deep.


Power/Ground/Turn-On Connections: The JH805 features set-screw terminals for the Power, Ground and Remote turn-on lead. The Power and Ground terminals will accommodate up to an 4 AWG wire, while the Remote turn-on lead will accept up to a 16 AWG wire.

RCA Inputs: The three pair of RCA type line-level inputs have gain (Input Sensitivity) control. The Input Sensitivity control will accept an input signal of 250mV to 5.0 Volts.

Smart-Engage Speaker Level Input: The Jack Hammer JH805 comes with a set of speaker level input harnesses. This feature makes it easier to add an amplifier to a factory radio or to a receiver with no preamp outputs. When using the speaker-level inputs, the amp automatically turns on when it senses signal from the head unit, eliminating the need for a remote turn-on connection. In many cases, this feature will allow you to install the amplifier without removing your radio.

Speaker Connections: The amplifier is equipped with six pairs of speaker terminals for connection of 4 pairs of speakers and a subwoofer(s). The amplifier uses set-screw speaker terminals which will accommodate 12 to 8 AWG speaker wire.

EBC: RJ-11 connection for connecting the supplied wire remote bass knob.

Fuse: The amplifier is equipped with three 30-AMP fuses.

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