JL Audio builds their hard-working G-Series amplifiers with the high-end technology that's made their amps legendary. An advanced thermal and low-impedance protection system doesn't shut your amp down when the going gets tough. Instead, it rolls back peak voltage demands to protect the amp, while continuing to play your music at a safe power level. "Differential-balanced inputs" reduce noise by isolating the signal's ground from the chassis ground, making these amps compatible with almost any system, including most factory radios.

The G-MAX mono amplifier delivers up to 1,200 watts RMS to your subwoofers, and patented Class-D circuitry exerts tight control over your bass system for extreme accuracy. Tunable frequency filters give you precise control over your sound, and a switchable bass boost lets you add a little punch. The optional RBC-1 remote converts the bass boost into a fully variable control that you can adjust from the comfort of your front seat.

Product Highlights:

  • mono subwoofer amplifier
  • at 14.4 volts:
    • 600 watts RMS x 1 at 4 ohms (1,200 watts RMS x 1 at 2 ohms)
  • at 12.5 volts:
    • 450 watts RMS x 1 at 4 ohms (900 watts RMS x 1 at 2 ohms)
  • differential-balanced inputs
  • Advanced Rollback Protection System
  • frequency response: 10 Hz - 250 Hz
  • variable low-pass filter (40-200 Hz, 12 or 24 dB/octave)
  • switchable bass boost (0, 6 dB at 48 Hz)
  • optional wired remote control converts switchable bass boost to fully variable (0-12 dB)
  • Absolute Symmetry™ Class-D amplifier design
  • MOSFET power and output stages
  • preamp-level inputs
  • speaker-level input with optional converter
  • preamp outputs
  • 4-gauge power and ground leads and a 80-amp fuse recommended — wiring and hardware not included with amplifier
  • no onboard fuses — when installing multiple amps in a system, an additional 80-amp in-line fuse between the distribution block and the amplifier is recommended
  • 9-1/4"W x 2-1/2"H x 16-1/8"D
  • warranty: 90 days
  • 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.

Hands-on research

What's in the box?

Download owner's manual

  • Monoblock subwoofer amplifier
  • 2.5mm Allen wrench
  • Owner's Manual

Product Research

Features
Controls
Connections

Features

Mono-Channel Subwoofer Amplifier: The JL Audio G-MAX is a class D monoblock subwoofer amplifier that is  rated at 600 Watts RMS x 1-channel in 4 ohm at 20 to 250Hz with a signal-to-noise-ratio of  90 dB and a total harmonic distortion of 1% while receiving 14.4 Volts. The amplifier is rated at 1200 Watt RMS x 1-channel in a 2 ohm load at 14.4 Volts. While receiving 12.5 Volts the amplifier is rated at 450 Watts RMS x 1-channel in 4 ohm with a total harmonic distortion of 1% or 900 Watts RMS x 1-channel in 2 ohm. The JL Audio subwoofer amplifier's frequency response is limited to the range of 10-250Hz and is not designed for driving midrange speakers or tweeters. Every aspect of the amplifier's operation has been optimized for low-frequency amplification.

Class D Circuitry: This JL Audio Class D subwoofer amplifier utilizes a proprietary Class D circuit. JL Audio's Patented Class D output circuit utilizes a discrete control section and a unique feedback loop design that results in outstanding power regulation and a damping factor greater than 500 at 4 ohms (>250 at 2 ohms). This is vastly higher than other Class D designs and also higher than most Class A/B amplifiers. The benefit of this exclusive JL Audio technology is tight, clean bass reproduction with the efficiency advantage of Class D amplification.

Simplified Gain Setting: The G-Series amplifier makes setting the gain level of the amp via the input sensitivity control very simple. All you need is Digital AC Voltmeter (142TK12V, sold separately) and a Test CD Disc (503CD104, sold separately) with a sine-wave test-tone recorded at 0 dB reference level in the frequency range to be amplified for that set of channels (50 Hz for subwoofer channels, 1 kHz for a midrange application).

Differential-Balance Inputs: The JL Audio amplifier features differential-balanced input architecture to effectively control noise and ensure compatibility with a wide variety of source units, including many OEM systems. Without resorting to line output converters, you can directly connect most OEM source units to the JL Audio amplifier without creating any noise or compatibility issues. Unlike conventional single-ended inputs, the differential-balanced design does not connect one side of the audio signal to chassis ground.  This eliminates any voltage sensitivity between one input terminal and ground and greatly reduces the incidence of alternator whine in a typical car audio installation. The G-MAX amplifier provides range switching on each of its inputs via the "Input Voltage" switch. This permits connection to a wide range of source voltages while retaining excellent sensitivity setting precision.

Note: (136XDCLR2S, sold separately) to connect this amplifier to your headunit via speaker-level.

Preamp Outputs: The G-Series amplifier features one pair of preamp outputs that make connecting multiple amplifiers simple. The preamp pass-through outputs are configured in parallel with the amp inputs. The signal present at these outputs is identical to the signal at the amp inputs and is unaffected by any on-board processing.

Advanced Rollback Protection: Should an G-Series amplifier ever overheat, its intelligent, unregulated power supply reacts by limiting available peak voltage until the amplifier returns to a safe temperature range. Likewise, if an impedance lower than optimal for the amplifier is present at the outputs, the G-Series amplifier will roll back peak voltage to protect itself without shutting down.

Note: There is only one condition that will shut down the G-Series amplifier completely and that is if the battery voltage of your vehicle drops below 10 volts.

Protection Circuitry With Status Indicator Lights: There are two status indicator lights on the right side of the amplifier.

  • Power (Green): This LED lights green to indicate that the amplifier is turned on and operating normally.
  • Protect (Red): The Protection LED lights Red to indicate the amplifier's protection circuitry has been activated to prevent product failure due to a short-circuit or a dangerously low impedance connected to the amplifier's outputs.

Controls

Active Crossover: The active crossover sections of the G-Series amplifier offer excellent flexibility and precise tuning. The G-MAX features the following crossover adjustments.

  • Low Pass Filter: You can select a 12 dB/octave Low Pass or 24 dB/octave Low Pass. You can also turn the amplifier's Low Pass crossover off if you choose to use an external electronic crossover. In the Off mode the amplifier has a frequency range up to 250 Hz.
  • Filter Frequency: The filter frequency for the 12dB/octave or 24dB/octave Low Pass crossover can be set from 40 to 200 Hz.

Bass Controls: The bass boost circuit of the G-Series amplifier offers the following controls.

  • Bass Boost: The amplifier is equipped with a fixed +6dB, 48 Hz Bass Boost.
  • Remote Bass Port: The amplifier is equipped with a connection for a wired Remote Bass Control (136RBC1, sold separately) that allows fully variable boost control (0-12dB) from the front of your vehicle.

Connections

Left Side Of Amplifier:

  • Power and Ground: The JL Audio amplifier's set-screw Power and Ground connections are designed to accept 8 to 4 AWG power wire.
  • Remote Turn-On: The G-Series amplifier's set-screw turn-on lead will accept 18 to 12 AWG  wire.
  • Speaker Outputs: The G-MAX amplifier's set-screw speaker terminals will accept 16 to 8 AWG speaker wire.

Note: The Amplifier is not equipped with a fuse. An external 80-amp AFS, ANL, or MAXI fuse (not included) must be installed on the power wire. If a wiring kit is used which includes a fuse with a value other than 80-amps, the original should be replaced with a 80-amp fuse

Right Side Of Amplifier:

  • Preamp Inputs: The amplifier features one set of differential-balanced RCA jack inputs. The amplifier's input level can be set to Low (200mV-2V RMS) when connecting the amplifier to a low-level preamp signal or set to High (800mV-8V RMS) when connecting the amplifier to a high-level speaker signal.
  • Preamp Outputs: The amplifier also features one set of pass-through preamp outputs so you can send an unaltered audio signal to another amplifier in your system.
  • Remote Bass Port: The amplifier is equipped with a connection for a wired Remote Bass Control (136RBC1, sold separately).

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Get everything you’ll need to enjoy your new JL Audio G Series G-MAX

You'll need an amp wiring kit to install your new amplifier, as wiring is not included.
Bring the music from your amp to your speakers.
Patch cables take the music from your stereo to the amplifier. Most amp wiring kits don't include them.
Add a remote and control your amp from the driver's seat.
For multi-amp systems, you'll need a separate fuse holder.
Helps protect your car's charging system and improves power handling. Required power and ground wires not included with cap.
The right tools will make the installation easier.
Have your new amplifier put in by a qualified professional in your area.
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