JL Audio J2320.4 owner manual Turn-On Lead, Input Sections, Input Sensitivity Controls

Turn-On Lead

The J2-320.4 is turned on and off using a conventional +12V remote turn- on lead, typically controlled by the source unit’s remote turn-on output.

+ ￿￿VDC Remote

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The amplifier will turn on when +12V is present at its “Remote” input and turn off when +12V is switched off. If a source unit does not have a dedicated remote turn-on output, the amplifier’s turn-on lead can be connected to +12V

via a switch that derives power from an ignition- switched circuit.

18 AWG wire is more than adequate for the remote turn-on connection. To connect the remote turn-on wire to the amplifier, strip 1/2-inch (12 mm) of insulation from the wire and insert it into the “Remote” receptacle on the power connector. Tighten the connector down using a Phillips screwdriver.

Input Sections

The J2-320.4’s has two input sections: one for Channels 1&2 and another for Channels 3&4. These input sections allows you to send signals to the amplifier sections through the use of either two or four inputs. Each input section offers two input connection methods, one for high- level (speaker level) signals and one for low-level (preamp level) signals.

1)Low-Level Inputs: A standard left/ right pair of RCA type jacks in the “Amplifier Inputs” section is used for preamp level (low-level) signal input on the J2-320.4. This is the preferred connection method whenever available.

Amplifier Inputs

CH 1 (Left) CH 3 (Left)

CH 2 (Right) CH 4 (Right)

2)High-Level Inputs: If your system does not offer a preamp level signal option, you can connect speaker level signals directly to the “High-Level Inputs” connectors using the supplied mating connectors and wire harnesses. Simply splice the appropriate left/right and positive/negative wires to the included harnesses and plug the harness into the “High-Level Inputs” connectors on the amplifier. The J2-320.4 will attenuate the high- level signals to make them compatible with its input stages.

Channel 1 & 2 Contro

wer			In
High-Level Inputs			1
150	60	1.2k	m
w-Pass	High-Pass
Filter Frequency (Hz)			I

Make sure you observe correct polarity in making the “High Level Input” connections. Failure to do so will reduce bass and affect stereo imaging.

The connections for the “High Level Inputs” plug wires are as follows from left to right on the plug:

Channels 1&2 (FRONT)

White: Left Positive (+)

White/Black: Left Negative (–)

Black: Common Ground (rarely used)*

Gray: Right Positive (+)

Gray/Black: Right Negative (–)

Channels 3&4 (REAR or SUB)

Green: Left Positive (+)

Green/Black: Left Negative (–)

Black: Common Ground (rarely used)*

Purple: Right Positive (+)

Purple/Black: Right Negative (–)

*The only time you will use the Common Ground connections is with some older (pre-1980’s) factory systems or head units that ground their speakers to chassis ground. To use these connections, ground the black wires on the plugs to chassis ground and only connect the Left and Right Positive plug wires to the factory radio outputs.

“CH 3&4 Input From” Switch

If you wish to send four discrete channels of input into the J2-320.4, simply use all four inputs (Channels 1 & 2 and Channels 3 & 4) and set the “CH 3&4 Input From” switch to “3&4”.

2 Controls		Pre
	CH 3&4
	Input From
puts	1&2 3&4
1.2k	min max
Pass
z)	Input Sens.	R

If you wish to feed all four channels by using

only two channels of input, set the “CH 3&4 Input From” switch to “1&2” and use only the inputs to channels 1 & 2.

Input Sensitivity Controls

The controls labeled “Input Sens.” located in each “Channel Controls” section can be used to match the source unit’s output voltage to the input stage of each pair of amplifier channels 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.)

& 2 Controls		Pr
	CH 3&4
	Input From
nputs	1&2 3&4
1.2k	min	max
-Pass
Hz)	Input Sens.

To properly set the amplifier for maximum clean output, please refer to Appendix A (page

12)in this manual. After using this procedure, you can then adjust any or all “Input Sens.” levels downward if this is required to achieve the desired system balance.

Do not increase any “Input Sens.” setting for any channel(s) of any amplifier in the system beyond the maximum level established during the procedure outlined in Appendix A (page 12). Doing so will result in audible distortion and possible speaker damage.

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