JL Audio XD 400/4 User Manual

Thank you for purchasing a JL Audio amplifier for
your automotive sound system.
Your amplifier has been designed and manufactured to exacting
standards in order to ensure years of musical enjoyment in your vehicle.
For maximum performance, we highly recommend that you have
your new amplifier installed by an authorized JL Audio dealer. Your
authorized dealer has the training, expertise and installation equipment
to ensure optimum performance from this product. Should you
decide to install the amplifier yourself, please take the time
to read this manual thoroughly so as to familiarize yourself
with its installation requirements and setup procedures.
If you have any questions regarding the instructions in this
manual or any aspect of your amplifier’s operation, please contact your
authorized JL Audio dealer for assistance. If you need further assistance,
please call the JL Audio Technical Support Department
at (954) 443-1100 during business hours.
OWNER’S MANUAL
400W 2/3/4 Channel Amplier

JL Audio XD 400/4 Specifications

General

Channels	4
Rated Power (4 Ohms)	75W x 4
Rated Power (2 Ohms)	100 W
Rated Power (Bridged 4 Ohms)	200W x 2
Crossover	Variable high- and low-pass

Summary

Protect Your Hearing

Planning Your Installation

Product Overview

Typical Installation Sequence

Step-by-step guide for installing the amplifier correctly in a vehicle.

Power Connections and Fusing

Power Wire Connections

Guidelines for connecting the +12VDC and Ground wires using appropriate gauge wire.

Fuse Requirements

Importance and placement of the main power wire fuse for vehicle protection.

Signal and Turn-On Connections

Input Sensitivity Adjustment

Input Sensitivity Controls

Adjusting input gain for maximum clean output from source units and amplifier channels.

Filter Controls

Filter Mode and Frequency Settings

Speaker Outputs and Bridging

Speaker Output Connections

Bridging Considerations

Status Indicators and Service

Appendix A: Input Sensitivity Level Setting

Input Sensitivity Adjustment Procedure

Step-by-step guide to correctly set amplifier input sensitivity for optimal performance.

Appendix C: XD400/4 Specifications

Troubleshooting: Common Issues

Setting Input Sensitivity

Guidance on correctly setting amplifier input sensitivity for optimal performance.

Amplifier Power and Connection Issues

Troubleshooting power-on problems and connection integrity.

Speaker Noise and Output Issues

Troubleshooting: Power and Output Problems

Amplifier Shuts Off or No Output

Resolving issues where the amplifier turns off or has no audio output.