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JL Audio's J2 amplifiers will electrify you with strong performance at an affordable price, as these high-powered amps transform your system with their superb sound quality. Oversized output transistors, extra-quiet input circuitry, and high-tech power supplies deliver strong, stable output and reliable performance. These amps are overbuilt and underrated, so you'll get the maximum clean power you'd expect from JL Audio.

The J2 320.4 4-channel amp delivers 60 watts RMS per channel to your front and rear speakers, or you can send 160 watts RMS to a sub while sending 60 watts to each of your front speakers. Into bass? Switch this versatile amp to 2-channel mode, and drive two subs with 160 watts each. You can use the frequency filters and bass boost to tune your amp's sound to match your speaker system perfectly.

Product Highlights:

  • 4-channel car amplifier
  • 60 watts RMS x 4 at 4 ohms (80 watts RMS x 4 at 2 ohms)
  • 160 watts RMS x 2 at 4 ohms
  • Class B amplifier design
  • MOSFET switching power supply
  • frequency response: 10-25K Hz
  • variable low-pass filter (40-150 Hz, 12 dB/octave)
  • variable high-pass filter (60-1.2K Hz, 12 dB/octave)
  • variable bass boost (0-12 dB at 45 Hz)
  • preamp inputs and outputs
  • speaker-level inputs
  • fuse rating: 30A x 2
  • 4-gauge power and ground leads and a 60-amp fuse recommended — wiring and hardware not included with amplifier
  • 15-13/16"W x 2-3/16"H x 9-5/8"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.

JL Audio J2 320.4 Reviews

Average Customer Review:

2 Reviews


Written by: TJ from Houston, Tx on July 17, 2010

Before this, my speakers definitely lacked volume, and had much to be desired in clarity. It finally came in, and it makes me hate myself for not installing a 4 channel amp the moment my interest was caught in the world of car audio.The bass is tight and clean. And the mids and highs are so clear that I get shivers. I doubt I will ever be able to sit in a car again with stock speakers running off of a factory head unit. Thank you JL audio, this amp is at a reasonable price, with the same quality I would expect from a high end amplifier. Oh and it looks amazing too.



Supreme Qaulity

Written by: Cody from Bend, Oregon on January 27, 2010

I had no reservations on selecting this product, JL has always been a cut above, My view of the company is that they are not out to be the most profitable (pioneer, Sony etc..) but to be a high quality , high performance company.. bottom line, you can buy there low end product such as this amp and you will still get a high end quality product that you pay twice as much for with other brands, this thing is build like a tank and sounds amazing. I am currently running 2 10" subs and two component fronts ... mind you this is not a sub amp ... but it pounds the heck out of my subs, all while not distorting the quality its pouring to my fronts. I have the amp gain set at half to my fronts and 3/4 to the subs .. and the amp stays luke warm to the touch and its louder than is probably safe for human ears inside the cab of my truck, and crystal clear.

You wont be sorry you picked this one up...



Hands-on research

What's in the box?

Download owner's manual

  • 4-Channel full-range amplifier
  • Four 30 amp ATO fuses (2 installed)
  • 2mm Allen wrench
  • 3mm Allen wrench
  • Two 10" Speaker input harnesses
  • Four 3/4" Self-tapping screws
  • 4 Flat washers
  • Owner's manual

Product Research



Design: The JL Audio J2 320.4 is 4-channel class B amplifier rated at 60 watts RMS x 4 into a 4Ω load and 80 watts RMS x 4 into a 2Ω load. When bridged the output is 160 watts RMS x 2 into a 4Ω load and 120 watts RMS x 2 into an 8Ω load.

Status LEDs: There are two LEDs on the left side of the amplifier:

  • Power: green LED indicates the amplifier is turned on and operating normally
  • Protect: red LED indicates the amplifier has exceeded its safe operating temperature, detected a short in a speaker output, or the speaker impedance is too low


Active Crossover: The front and rear sections of the amp have individual crossovers. Each can be set to high-pass, low-pass, or off (full range). The crossover points are also individually adjustable; each high-pass is continuously variable from 60 Hz to 1.2 kHz and each low-pass is continuously variable from 40 Hz to 150 Hz. The slope of both crossovers is 12 dB/octave.

Bass Boost: The front and rear sections of the amp also have separate bass boost circuits. Each is adjustable from 0 to +12 dB; the boost frequency is fixed at 45 Hz.


Power and Ground: The Power and Ground connections accept 4 gauge wire, which JL Audio recommends as the minimum size. The set-screw terminals are tightened/loosened using the included 3mm Allen wrench.

Remote Turn-On: The remote terminal will accept 10 to 18 gauge wire. The set-screw terminal is tightened/loosened using the included 2mm Allen wrench.

Speaker Outputs: The speakers' set-screw terminals will accept 8 to 16 gauge speaker wire; they are tightened/loosened using the included 2mm Allen wrench.

Preamp Inputs: The amplifier features two sets of RCA line level inputs. The input sensitivity is adjustable from 200mV to 4V RMS.

Speaker Inputs: When connecting the amp to a head unit without line level outputs, use the included speaker level input harnesses. In this case the input sensitivity is adjustable from 2V to 10V RMS.

Preamp Outputs: There is a pair of preamp outputs so you can send audio to another amplifier in your system. The preamp output is not affected by the crossover or bass boost circuits.


Our Product Research Team

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