JL Audio 300/2 owner manual Bridging Considerations, Status Indicator Lights Protection Circuitry

BRIDGING CONSIDERATIONS

Bridging is the practice of combining the output of two amplifier channels to drive a single load. When bridged, each channel produces signals of equal magnitude, but opposite polarity.The combined output of the two channels provides twice the output voltage available from a single channel.The 300/2 has been designed for bridging of its channel pairs without the need for input inversion adaptors.

To bridge a pair of channels, use the “Left +” and “Right –” speaker connectors only (the “Left –” and “Right +” remain unused). When bridged, the 300/2 will deliver optimum power into a 3 - 8Ω load. Operating a bridged 300/2 into a load lower than 3Ω 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 source unit. Connection of only one RCA input will result in reduced power output, increased distortion and can cause the amplifier to overheat. Do not do this! Instead, use a “Y-Adaptor” to split the mono signal into both left and right RCA inputs.

Why a mono signal? 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.

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 self- protection 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 Ω” (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 the amplifier.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 channel at a time.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 300/2 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 14).

SERVICINGYOUR 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

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