Features
Inputs and Outputs Notes

Features

Marine Rated: The JL Audio Marine Amplifiers (M-Series) take the basic design of the JL Audio G-Series car audio amplifiers and adapt them for use on the water in your boat or vessel. The JL Audio Marine-rated amplifiers are constructed from UV-resistant materials with corrosion-resistant hardware.

Four-Channel Full-Range Amplifier: The JL Audio M4500 is a class AB full-range amplifier that is rated at 80 Watts RMS x 4-channel in 4 ohm at 20 to 20,000Hz with a signal-to-noise-ratio of 104 dB and a total harmonic distortion of 1% while receiving 14.4 Volts or 60 Watts RMS x 2-channel in 4 ohm with a total harmonic distortion of 1% while receiving 12.5 Volts. The amplifier can be bridged to output 250 Watts RMS x 2-channel in 4-ohm at 14.4 Volts or 180 Watts RMS x 2-channel in 4-ohm at 12.5 Volts.

Absolute Symmetry A/B Circuitry: The JL Audio full-range amplifier benefits from a patented technology called Absolute Symmetry to deliver amazing fidelity with extremely low distortion over a wide range of load impedances. The JL Audio amplifier features a revolutionary Class A/B circuit that employs identical N-Channel MOSFET transistors for push and pull with true buffering from the load impedance. This is accomplished via a patented circuit that reverses the operation of one of the transistors in each pair to achieve absolute power symmetry and extremely low distortion over a wide range of load impedances.

Simplified Gain Setting: The M-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 M4500 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.

Flexible Preamp Outputs: The M-Series amplifier features one pair of preamp outputs that make connecting multiple amplifiers simple. The M4500 features pass-through preamp outputs which can take their input from the amplifier's 1 & 2 channels or from the sum of all four channels.

Active Crossover: The M-series amplifier provides a crossover network to fine tune your system effectively and accurately. The M4500 offers the following independent crossover adjustments for the 1 & 2 and 3 & 4 channels.

• Filter Mode: The amplifier allows you to select either a Low Pass, High Pass or Full-Range operation of the amplifier's 1 & 2 channels and 3 & 4 channels.
• Variable Frequency: You can set the amplifier's Low Pass or High Pass crossover from 50 to 200 Hz for channels 1 & 2 and channels 3 & 4.

Bass Controls: The bass boost circuit of the M-Series amplifier offers the following controls that only effect channels 3 & 4 of the amplifier.

• 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.

Advanced Rollback Protection: Should an M-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 M-Series amplifier will roll back peak voltage to protect itself without shutting down.

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.

Inputs and Outputs Notes

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 M-Series amplifier's set-screw turn-on lead will accept 18 to 12 AWG  wire.
• Speaker Outputs: The M4500 amplifier's eight set-screw speaker terminals will accept 16 to 8 AWG speaker wire.

Right Side Of Amplifier:

• Preamp Inputs: The amplifier features two sets 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).