User manual JL AUDIO 300-4

[. . . ] JL AUDIO 300/4 four-channel full-range amplifier o w n e r 's m a n u a l 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 and extended warranty coverage, 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. [. . . ] I M P O RTA N T If you connect a load higher than 4 nominal per channel in stereo mode (or 8 in bridged mode), power will drop by half with every doubling of impedance above 4 stereo / 8 mono. If you connect a load lower than 1. 5 nominal per channel in stereo mode (or 3 in bridged mode, the amplifier protection circuitry activates a "safe" mode which reduces amplifier power to protect the circuitry from failure (the yellow "Low " LED lights to indicate that this has happened). I M P O RTA N T Speaker loads below 1. 5 nominal per channel in stereo or 3 nominal in bridged mode are not recommended and may cause the amplifier output to distort excessively. To bridge a pair of channels, use the "Left +" and "Right ­" speaker connectors only (the "Left ­" and "Right +" remain unused). Then connect a mono signal to both left and right RCA inputs for that channel pair. This requires an RCA "Y-Adaptor" (not included. ) When bridged, each channel pair will deliver optimum power into a 3-8 load. Operating bridged channel pairs into a load lower than 3 is not recommended. Because a bridged pair of channels requires that both channels receive input, you need to connect both left and right RCA inputs to the bridged channel pair's inputs. Connection of only one RCA input will result in reduced power output, increased distortion and can cause the amplifier to overheat. Instead, use a "Y-Adaptor" to split the mono signal into both left and right RCA inputs. If you are bridging a pair of channels and use a stereo input, the only information that will reach the amplifier stage is the common-phase portion of the signal. This may be useful for passively deriving a center-channel signal, but is not going to give you a defined left or right channel. If you are looking to reproduce a single channel's signal, you must split the mono signal with a "Y-Adaptor" and connect it to both left and right RCA inputs for the bridged channel pair. 8 JL AUDIO 300/4 JL AUDIO 300/4 9 STATUS INDICATOR LIGHTS / PROTECTION CIRCUITRY There are three status indicator lights on the top of the amplifier. These are as follows: 1) "Power" (Green): lights to indicate that the amplifier is turned on and operating normally. 2) "Thermal" (Red): lights to indicate that the amplifier has exceeded its safe operating temperature, putting the amplifier into a selfprotection mode, which reduces the power output of the amplifier. The red light will shut off and the amplifier will return to normal, full-power operating mode if the heat sink temperature drops back to a safe level. 3) "Low " (Amber): lights to indicate that the impedance of the speaker load connected to the amplifier is lower than the optimum load impedance range for the amplifier. When this light is on, a protection circuit engages and reduces the power output of all four amplifier channels. The amber indicator will also light when a short-circuit is detected in the speaker wiring (this can be a short between the positive and negative speaker wires or between either speaker wire and the vehicle chassis). This can be used to diagnose a short-circuit by only connecting one of the amplifier sections at a time (front or rear). The amber LED will light when you connect the section that is experiencing the problem and turn the volume up. There is only one condition that will shut down an undamaged 300/4 completely. . . If battery voltage drops below 10 volts, the entire amplifier will shut itself off. The green "Power" indicator on the top of the amplifier will turn off when this occurs. The amplifier will turn back on when voltage climbs back above 10 volts. This may happen in a rapid cycle when bass-heavy program material causes a weak charging system to dip below 10 volts momentarily. If this is happening in your system, have your charging system inspected to make sure it is working properly. A 0. 5 or 1. 0 Farad rapid-discharge capacitor connected in parallel to the amplifier power connections will minimize these short duration voltage dips in most systems that are having this problem. For information on troubleshooting this amplifier, refer to Appendix C (page 18). SERVICING YOUR JL AUDIO AMPLIFIER If your amplifier fails or malfunctions, please return it to your authorized JL Audio dealer so that it may be sent in to JL Audio for service. There are no user serviceable parts or fuses inside the amplifier. The unique nature of the circuitry in the JL Audio amplifiers requires specifically trained service personnel. Do not attempt to service the amplifier yourself or through unauthorized repair facilities. This will not only void the warranty, but may result in the creation of more problems within the amplifier. If you have any questions about the installation or setup of the amplifier not covered in this manual, please contact your dealer or the JL AUDIO Technical Department for assistance: (954) 443-1100 9:00 AM ­ 5:30 PM Eastern Time, Monday ­ Friday SYSTEM CONFIGURATIONS The 300/4 is a flexible amplifier, well-suited for a multitude of system configurations. In this section, the most likely configurations are explained in detail. [. . . ] Check the RCA connectors to ensure that both the center pin and the outer shield are making good contact with the input jacks on the amplifier. "HOW DO I PROPERLY SET THE INPUT SENSITIVITY ON MY AMPLIFIER" Please refer to Appendix B (page 14) to set the input sensitivity for maximum, low-distortion output. 18 JL AUDIO 300/4 JL AUDIO 300/4 19 APPENDIX D: 300/4 Specifications GENERAL SPECIFICATIONS: Recommended Fuse Value: 40A Recommended Fuse Type: AGU or MaxiFuseTM INPUT SECTIONS: No. of Inputs: Two Stereo Pairs (Front, Rear) Input Type: Differential-balanced with RCA jack inputs Input Range: Switchable from 200mV - 2V RMS to 800mV - 8V RMS AMPLIFIER SECTIONS: Amplifier Topology: Class AB with patented Absolute SymmetryTM dual N-Channel MOSFET output design Power Supply: Independent, pulse width modulationregulated switching power supply with multistage impedance optimizing circuitry. Rated Power (Stereo): 75W RMS x 4 @ 1. 5-4 (11V - 14. 5V) Rated Power (Bridged): 150W RMS x 2 @ 3-8 (11V - 14. 5V) THD at Rated Power: <0. 03% @ 4 per channel (20 Hz-20 kHz) Signal to Noise Ratio: >108. 5 dB referred to rated power (A-weighted, 20 Hz-20 kHz noise bandwidth) Frequency Response: 5 Hz - 30 kHz (+0, -1dB) Damping Factor: >200 @ 4 per ch. / 50 Hz Slew Rate: ± 25V/µs FILTER SECTIONS: Front and Rear Filters (2): State-variable, 12 dB/octave Butterworth or 24 dB/octave Linkwitz-Riley low-pass or high-pass with continuously variable cutoff frequency from 50 - 500 Hz, switchable to a range of 500 - 5000 Hz, via x10 switch. [. . . ]