For optimum cooling performance, this outer shell should be exposed to as large a volume of air as possible. Enclosing the amplifier in a small, poorly ventilated chamber can lead to excessive heat build-up and degraded performance. If an installation calls for an enclosure around the amplifier, we recommend that this enclosure be ventilated with the aid of a fan. In normal applications, fan-cooling is not necessary. Speaker Outputs (pg. 10) Speaker Output (Mono) IMPORTANT! Mounting the amplifier upside down is strongly discouraged. If mounting the amplifier under a seat, make sure there is at least 1 inch (2.5 cm) of space above the amplifier’s outer shell to permit proper cooling. safety considerations: Your amplifier needs to be installed in a dry, well-ventilated environment and in a manner which does not interfere with your vehicle’s safety equipment (air bags, seat belt systems, ABS brake systems, etc.). You should also take the time to securely mount the amplifier using appropriate hardware so that it does not come loose in the event of a collision or a sudden jolt to the vehicle. stupid mistakes to avoid: • 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. • Do not run system wiring outside or underneath the vehicle. This is an extremely dangerous practice which can result in severe damage to your vehicle and person. • Protect all system wires from sharp metal edges and wear by carefully routing them, tying them down and using grommets and loom where appropriate. • Do not mount the amplifier in the engine compartment, under the vehicle, on the roof or in any other area that will expose the amplifier circuitry to the elements. Product descriPtion The JL Audio J2-250.1 is a monoblock subwoofer amplifier utilizing Class A/B technology. Its frequency response is limited to the range below 100 Hz. It is not designed for driving midrange speakers or tweeters. It has been optimized for low-frequency amplification. For detailed specifications, please refer to Appendix B (page 13). tYPical installation sequence The following represents the sequence for a typical amplifier installation, using an aftermarket source unit or OEM Interface product. 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. 1) Disconnect the negative battery post connection and secure the disconnected cable to prevent accidental re-connection during installation. This step is not optional! 2) Run power wire (minimum 8 AWG) from the battery location to the amplifier mounting location, taking care to route it in such a way that it will not be damaged and will not interfere with vehicle operation. Use 4 AWG, 2 AWG or 1/0 AWG power wire if additional amplifiers are being installed with the J2-250.1. 3) Connect power wire to the positive battery post. Fuse the wire with an appropriate fuse block (and connectors) within 18 inches (45 cm) wire length of the positive battery post. This fuse is essential to protect the vehicle. Do not install the fuse until the power wire has been connected to the amplifier. 4) Run signal cables (RCA cables) and remote turn-on wire from the source unit to the amplifier mounting location. 5) Run speaker wire from the speaker systems to the amplifier mounting location. 6) Find a good, solid metal grounding point close to the amplifier and connect the negative power wire to it using appropriate hardware. Use minimum 8 AWG power wire, no longer than 36 inches (90 cm) from the amplifier to the ground connection point. In some vehicles, it may be necessary to upgrade the battery ground wire. (See page 5 for important notice). 7) Securely mount the amplifier using appropriate hardware. 8) Connect the positive and negative power wires to the amplifier. 9) Connect the remote turn-on wire to the amplifier. 10) Connect the RCA input cables to the amplifier. 11) Connect the speaker wires to the amplifier. 12) Carefully review the amplifier’s control settings to make sure that they are set according to the needs of the system. 13) Install power wire fuse (30A for a single J2-250.1) and reconnect the negative battery post terminal. 14) Turn on the source unit at a low level to double-check that the amplifier is configured correctly. Resist the temptation to crank it up until you have verified the control settings. 15) Make necessary adjustments to the input sensitivity controls to obtain the right overall output and the desired balance in the system. See Appendix A (page 12) for the recommended input sensitivity setting method. 16) Enjoy the fruits of your labor with your favorite music. JL Audio Power connections Before installing the amplifier, disconnect the negative (ground) wire from the vehicle’s battery. This will prevent accidental damage to the system, the vehicle and your person durin...