OWNER’S MANUAL 250/1 Class D Monoblock Subwoofer Amplifiers 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.
PROTECT YOUR HEARING! We value you as a long-term customer. For that reason, we urge you to practice restraint in the operation of this product so as not to damage your hearing and that of others in your vehicle. Studies have shown that continuous exposure to high sound pressure levels can lead to permanent (irreparable) hearing loss. This and all other high-power amplifiers are capable of producing such high sound pressure levels when connected to a speaker system.
INSTALLATION APPLICATIONS This amplifier is designed for operation in vehicles with 12V, negative-ground electrical systems. Use of this product in vehicles with positive ground and/or voltages other than 12V may result in damage to the product and will void the warranty. This product is not certified or approved for use in aircraft. Do not attempt to “bridge” the outputs of this amplifier with the outputs of a second amplifier, including an identical one.
TYPICAL INSTALLATION SEQUENCE The following represents the sequence for a typical amplifier installation, using an aftermarket source unit or OEM Interface processor (like the JL Audio FiX™ 82 or FiX™ 86). Additional steps and different procedures may be required in some applications. If you have any questions, please contact your authorized JL Audio dealer for assistance.
The amplifier’s “+12 VDC” and “Ground” connections are designed to accept up to 4 AWG copper power wire. Minimum Power / Ground Wire Size Requirements: JD250/1: 8 AWG JD500/1: 4 AWG JD1000/1: 4 AWG If you are installing this amplifier with other amplifiers, use a main power wire that is appropriately sized for the overall current demands of all the amplifiers in the system.
TURN-ON OPTIONS JD monoblock amplifiers can be switched on and off using one of three methods, determined by the position of the amplifier’s “Turn-On Mode” switch. Please read these options and decide which is best suited for your specific system. 1) +12V Remote turn-on lead 2) DC Offset-Sensing turn-on circuit 3) Signal-Sensing turn-on circuit +12V Remote Turn-On: This is the preferred method for turning the amplifier on/off.
INPUT SECTION JD monoblock amplifiers employ a differentialbalanced input topology that provides the user with a high degree of input flexibility, while retaining superior noise rejection. This type of circuit also allows the amplifier to accept highvoltage inputs from factory source unit outputs without excessive distortion or noise problems. INPUT VOLTAGE RANGE A wide range of signal input voltages can be accommodated by the amplifier’s input section (200mV – 8V).
INPUT SENSITIVITY CONTROLS The “Input Sens.” control is used to match the source unit’s output voltage to the input stage of the amplifier for maximum clean output. Rotating the control clockwise will result in higher sensitivity (louder for a given input voltage). Rotating the control counter-clockwise will result in lower sensitivity (quieter for a given input voltage). The “Input Sens.” control is equipped with a LED “Clipping” trim ring to simplify the input sensitivity setting process.
“BASS BOOST” CONTROL JD monoblock amplifiers feature a single band, boost-only bass equalizer controlled by a rotary knob marked “Bass Boost (dB)”. This control has a boost range of 0 dB (full-counterclockwise) to +12 dB (full-clockwise) and is centered at 45 Hz. PREOUTS JD monoblock amplifiers include a buffered, pass-through preamp output section, so that additional amplifiers can be easily added to the system. The preamp output delivers the same signal that is connected to the amplifier’s inputs.
11.40 in SUBWOOFER OUTPUTS STATUS LEDS / PROTECTION CIRCUITRY JD monoblock amplifiers are designed to JD amplifiers are equipped with separate deliver power into subwoofer loads equal to or Status and Protection LEDs on the top surface greater than 2 ohms of nominal impedance. of the amplifier to indicate the amplifier’s The subwoofer outputs are designed to accept operating condition. 16 AWG - 8 AWG wire.
All LEDs Off / Amplifier Shuts Off Unexpectedly: The only condition that will shut down an undamaged JD amplifier completely is if battery voltage or remote turn-on voltage drops below 10 volts. When this occurs, both LEDs will turn off. The amplifier will turn back on when voltage climbs above 11 volts. If this is happening in your system, have your charging system and power wiring inspected. For more information on troubleshooting this amplifier, refer to Appendix C (pages 14, 15).
APPENDIX A: Input Sensitivity Level Setting Follow the steps below to adjust the input sensitivity of each amplifier channel pair, simply and easily, in just a few minutes to achieve overall system balance. Necessary Equipment • Sine-wave test tone recorded at 0 dBfs reference level in the frequency range to be amplified for that set of channels (50 Hz for subwoofer amplifier models or 1 kHz for a full range amplifier models). Do not use attenuated test tones (-10 dB, -20 dB, etc.).
APPENDIX B: Specifications JD250/1 Specifications: JD1000/1 Specifications: Amplifier Topology: NexD™ High Speed Class D Amplifier Topology: NexD™ High Speed Class D Power Supply: Unregulated MOSFET switching type Power Supply: Unregulated MOSFET switching type Frequency Response: 7 Hz - 500 Hz (+0, -1dB) Frequency Response: 7 Hz - 500 Hz (+0, -1dB) Signal to Noise Ratio: >80 dB referred to rated power (A-weighted, 20 Hz-20 kHz noise bandwidth) >60 dB referred to 1W (A-weighted, 20 Hz-20 kHz noise b
APPENDIX C: TROUBLESHOOTING “How do I properly set the input sensitivity on my amplifier?” Please r efer to Appendix A (page 12) to set the input sensitivity for maximum, low-distortion output. “My amplifier doesn’t turn on.” Check t he fuse, not just visually, but with a continuity meter. It is possible for a fuse to have poor internal connections that cannot be found by visual inspection. It is best to take the fuse out of the holder for testing.
“My amplifier shuts off once in a while, usually at higher volumes.” Check your voltage source and grounding point. The power supply of the amplifier will operate with charging system voltages down to 10V. Shutdown problems at higher volume levels can occur when the charging system voltage (or remote turn-on voltage) drops below 10V. These dips can be of very short duration making them extremely difficult to detect with a common DC voltmeter.
INSTALLATION NOTES: Use this diagram to document your amplifier’s switch and control positions.
JD250/1 • JD500/1 • JD1000/1 17
NOTES 18 JL Audio
NOTES JD250/1 • JD500/1 • JD1000/1 19
LIMITED WARRANTY - AMPLIFIERS (USA) JL AUDIO warrants this product to be free of defects in materials and workmanship for a period of two (2) years. The warranty is extended to three (3) years total if installation is performed by an authorized JL Audio dealer using a JL Audio Premium Power Connection System for power wiring. This warranty is not transferrable and applies only to the original purchaser from an authorized JL AUDIO dealer.
