Amplifier Mounting Options

The HD600/4 has two mounting options to ease in installation.

Standard Mounting

The standard method of mounting requires removal of the four corner caps with the 3/16-inchhex wrench included with your amplifier. Using appropriate mounting screws (not included), secure the amplifier in all four corners and replace the corner caps.

Lateral Mounting Feet

Lateral Mounting Feet are also included with your HD600/4 to provide an alternative mounting option. Each mounting foot should be attached to the bottom of the amplifier by screwing the provided bolt into the bottom of the amplifier and up into the corner cap with the supplied 1/8-inch hex wrench. Next, using appropriate mounting screws (not included), secure the amplifier by its four Lateral Mounting Feet.

Check before drilling any holes in your vehicle to make sure that you will not be drilling through a gas tank, brake line, wiring harness or other vital vehicle system.

ConTROL PAnel SECURITY CoVER

The HD600/4 features a Control Panel Security Cover. When installed, the cover ensures that your amplifier settings are not accidentally changed while creating a clean aesthetic for the amplifier and your installation. The control panel security cover is pre-installed at the factory and must be temporarily removed for access to the controls described throughout this manual.

The security cover is secured by a single 2.5

mmhex-head screw at the far right of the panel. Loosen the hex-head screw to release the security cover (it is not necessary to completely remove the screw). To re-install the security cover once all adjustments have been made, insert the tongue on the cover’s left edge into the groove where the left- side heatsink meets the control panel, hinge the panel closed and secure the screw using the supplied 2.5 mm hex wrench. Do not overtighten the screw.

AMPLIFIER INPuTS

The HD600/4 has two separate input sections, one for the “Front” left and right channels and another for the “Rear” left and right channels. Each section consists of a pair of RCA-type input jacks on the Connection Panel of the amplifier and a pair of input controls on the Control Panel of the amplifier: an “Input Voltage” switch and an “Input Sens.” rotary control.

mote	L
Front	Inputs	Rear	P
	R

“Input Mode” Switch

The Control Panel houses an “Input Mode” switch located under the “General Setup” heading. This switch allows operation of all four amplifier channels with only one pair of input signals or with independent front and rear input signal pairs.

To use separate inputs for the “Front” and “Rear” amplifier sections, (in order to permit front-to-rear fading, for example), select “4 Ch.” on the “Input Mode” switch. In this mode, you must connect separate pairs of input cables to the “Front” and “Rear” amplifier inputs.

To operate all four channels of the HD600/4 with a single pair of stereo inputs, select the “2 Ch.” position on the “Input Mode” switch and connect a single pair of input cables to the “Front” input jacks only. In this mode, the amplifier will route the signals connected to the “Front” inputs to the Front and Rear amplifier channels.

CHANNEL CONTROL SECTIONS

Flanking the “General Setup” section on the Control Panel of the amplifer are two sets of identical controls: one for the “Rear Channel Controls” (on the left side) and one for the “Front Channel Controls” of the amplifier (on the right side).

In each of these sections you will find an “Input Voltage” range switch and a rotary control labeled “Input Sens.” (Input Sensitivity). These controls are designed to match the input sensitivity of the HD600/4 to the specific signal source that is feeding it and must be adjusted, with care, following the procedures outlined in this manual. Failure to make correct adjustments can result in weak output, excessive distortion and/or undesirable noise in the audio output of the amplifier!

Note: The Channel Control sections also house “Filter Mode”, “Filter Slope” and “Filter Freq.” controls. These are crossover filter controls and will be discussed in the next section of this manual. This section will explain the Input Controls only.

8 JL Audio - HD600/4 Owner’s Manual

HD600/4 specifications

JL Audio's HD600/4 amplifier stands as a testament to the brand's dedication to quality and performance in the realm of car audio. Renowned for delivering powerful, clean sound, this amplifier is designed to meet the needs of audiophiles and casual listeners alike. With a compact design and impressive specifications, the HD600/4 is a four-channel amplifier that provides robust power to enhance your listening experience.

One of the standout features of the HD600/4 is its high-efficiency Class D topology. This technology allows the amplifier to produce more power while consuming less energy, resulting in a cooler operating temperature and less strain on your vehicle’s electrical system. The efficient design also means that the HD600/4 can deliver an astounding 75 watts RMS per channel at 4 ohms, and even more power when configured at lower impedances. This ensures clear and dynamic audio reproduction across a wide range of sources, from music to voice.

The HD600/4 also incorporates JL Audio's advanced signal processing capabilities. With adjustable crossover settings, users can precisely tailor the sound to match their specific requirements. The built-in high-pass and low-pass filters allow for easy integration with subwoofers and other speakers, ensuring a seamless audio experience regardless of the setup. Additionally, the amplifier features a line/ speaker level input, making it versatile enough to work with various audio sources.

Durability is another hallmark of the HD600/4. Constructed with high-quality materials, it features a robust aluminum chassis that not only enhances aesthetic appeal but also provides effective heat dissipation. The amplifier's design includes thoughtful engineering features such as a variable gain control per channel and advanced protection circuitry that safeguards against overheating and short circuiting.

The sleek and compact design of the HD600/4 makes it easier for installation in various vehicle types without sacrificing valuable space. With a mounting depth of just over 6 inches, it can fit into tight spaces, making it an attractive option for those seeking high-performance audio without the bulk of traditional amplifiers.

In conclusion, the JL Audio HD600/4 embodies high-quality engineering, power efficiency, and adaptability. Its combination of advanced technologies, user-friendly features, and robust build quality make it a top choice for car audio enthusiasts looking to elevate their listening experience to new heights. With the HD600/4, users can expect nothing less than the exceptional audio performance that JL Audio is known for.