Features
Controls
Connections

Features

Monoblock Class-D Amplifier: The JL Audio MHD750/1 is a very powerful and compact monoblock (single channel), wide-range amplifier utilizing patented Single Cycle Control Class D technology. This technology delivers reference grade sonic performance while requiring less current from the vessel's electrical system than a conventional amplifier. Unlike most monoblock amplifiers, the MHD750/1 has a wide frequency range so it can be used as a subwoofer amplifier or as a very powerful mid-bass or mid-range amplifier using a second MHD750/1 to form a stereo pair.

R.I.P.S. (Regulated, Intelligent Power Supply): The regulated power supply delivers consistent power output over a range of impedance loads and input voltages; 750 watts RMS x 1-channel into a 1.5Ω to 4Ω load, with an input voltage of 11 to 14.5 volts.

• Regulated Power Supply: Regulated means the power supply adjusts its operation to maintain the amplifier's rated power output and low distortion operation over a wide range of vehicle voltages (11-14.5 volts). The result is power stability in real-world 12-volt systems.
• Intelligent Power Supply: The Intelligent portion of the R.I.P.S. System is a circuit that monitors output current to optimize the amplifier's output power over a wide range of load impedances (1.5Ω to 4Ω). The R.I.P.S. system detects the actual impedance being driven and adjusts output rail voltages to deliver optimum output. This process is automatic and accounts for the real impedance of the speaker(s), rather than relying on often inaccurate assumptions based on a speaker's rated impedance.

Class D with Single-Cycle Control: The MHD750/1 utilizes a patented Single Cycle Control Class D technology. This technology tracks the audio signal, comparing it to the real PWM waveform and then correcting it over 400,000 times per second, distortion-causing mechanisms can be tightly controlled to enable pristine amplification.

Compact/Efficient Design: The MHD750/1 features an overall efficiency of 80% at ½ rated power, which leads to reductions in chassis size and current draw.

RealSink Heat Management With Rollback Protection: This amplifier employs RealSink heat management, with vertical cast alloy heat sink fins. The design of the heat sinks was refined through extensive finite-element analysis, resulting in amplifiers that stay cool under demanding conditions. If the amplifier ever reaches an unsafe temperature, the Advanced Rollback Protection circuit adjusts the power output until the amplifier cools down, without ever shutting your music down.

Differential-Balanced Inputs: The differential-balanced input architecture effectively controls noise and ensures 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 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 installation.

Mounting: The MHD series amps have three mounting options to choose from:

• Standard: The standard method of mounting requires removal of the four corner caps with the included 4mm Allen-wrench. Using the appropriate mounting screws (not included), you can then secure the amplifier in all four corners and re-install the corner caps.
• Mounting Feet: The included feet can be mounted to the bottom corners of the amp using the included machine screws. Including the feet, the with of the amp is 11.7" and the height is 2.145".
• Stacking: Using 136HDSTKIT Stack Kits (sold separately), multiple MHD amplifiers can be stacked on top of one another.

Controls

Control Panel Cover: The MHD750/1 features a control panel cover to protect and hide the amplifier's controls. When installed, the cover ensures that the amplifier's settings are not accidentally changed. The cover is pre-installed at the factory and must be removed to access the amplifier's controls. It's secured by a single 2.5mm Allen-head screw.

Gain: Because the amplifier's R.I.P.S. feature always delivers the same amount of power within its operational impedance and power supply voltage range, the maximum, unclipped output is predictable. This makes setting the gain level of the amplifier simple. You'll need a digital AC Voltmeter (1203320, sold separately) and an audio file with a 50 Hz sine-wave test-tone recorded at 0 dB reference.

Input Level: The range of the input sensitivity dial has two settings. Low is typically used for line-level sources (200mV-2V) and High for speaker-level (800mV-8V).

Crossover Network:

• Filter Mode: The amplifier features Full-Range (Off), High-Pass, and Low-Pass filter modes.
• Slope: The slope on the high-pass, and low-pass crossovers is switchable; choose 12dB/octave Butterworth or 24dB/octave Linkwitz-Riley.
• Frequency: The crossover point is variable from 50-500 Hz (actually 53-528 Hz) for the high-pass and low-pass crossovers.
• Infrasonic Filter: The Infrasonic Filter is a 24 dB/octave high-pass filter, with a fixed cutoff frequency of 30 Hz. This filter is designed to conserve amplifier power and protect subwoofer systems, without audibly degrading the sub-bass output. The Infrasonic filter can be turned off if you prefer.

Polarity: Depending on the distance relationship of the mid-bass speakers and the subwoofers in your system, it can be desirable to reverse the polarity of the subwoofer in order to produce a better transition between subwoofer and mid-bass speaker output. The amplifier's Output Polarity switch allows you to quickly perform this polarity inversion (0° or 180°).

Connections

Power/Ground/Turn-On: The amplifier features a Power/Ground/Turn-On plug that detaches from the amplifier to make connecting your power, ground, and remote turn-on lead wires more convenient. Once your connections are made, the plug connector simply snaps into the port on the amplifier.

• Power and Ground: The set-screw Power and Ground terminals accept up to 4-gauge wire. (4-gauge is recommended for any power cable longer than six feet.) A 4mm Allen-wrench is supplied for making the connections.
• Remote Turn-On: The set-screw turn-on terminal will accept up to 10-gauge wire. A 2.5mm Allen-wrench is supplied for making the connection.

Speaker Output: The amplifier also features a Speaker Output plug that detaches from the amplifier for easier speaker wire connection. Once your speaker wires are connected to this plug, it simply snaps into the port on the amplifier. There are outputs for two speakers, internally wired in parallel, making it easy to connect two subwoofers. The set-screw terminals will accept up to 10-gauge wire. A 2.5mm Allen-wrench is supplied for making the connections.

Preamp Inputs: The amplifier features one set of differential-balanced RCA jack inputs, used for both preamp and speaker-level inputs (200mV-8V).

Preamp Outputs: The MHD750/1 also has a pair of pass-through RCA preamp outputs, so that an additional amplifier can easily be connected without running another RCA cable. This output signal is buffered to prevent noise and is always preamp-level, regardless of the level of signals feeding the inputs.

Remote Level Control: With the addition of the optional wired Remote Level Control (136HDRLC, sold separately), you can control the output level of the MHD750/1. If desired, multiple MHD amplifiers can be controlled from a single HD-RLC controller using a simple phone line splitter and multiple phone cables (all sold separately).