JL Audio 300/2 owner manual Fuse Requirements TURN-ON Lead Input Section

FUSE REQUIREMENTS	TURN-ON LEAD	INPUT SECTION
It is absolutely vital that the main power wire(s)	The 300/2 uses a conventional +12V remote		The 300/2 has one input section, which contains a
to the amplifier(s) in the system be fused within	turn-on lead, typically controlled by the source unit's	pair of RCA-type input jacks, an “Input Voltage”
18 inches (45 cm) of the positive battery post	remote turn-on output.The amplifier will turn on	switch and an “Input Sens.” rotary control.
connection.The fuse value at each power wire	when +12V is present at its “Remote” input and
should be high enough for all of the equipment	turn off when +12V is switched off. If a source unit
being run from that power wire. If only the	does not have a dedicated remote turn-on output,
300/2 is being run from that power wire, we	the amplifier’s turn-on lead can be connected to
recommend a 40A fuse be used. AGU (big glass	+12V via a switch that derives power from an
fuse) or MaxiFuse™ (big plastic-body fuse) types	ignition-switched circuit.
are recommended.	The 300/2's “Remote” turn-on connector is
No fuse is required or recommended directly	designed to accept 18 AWG – 8 AWG wire.
before the amplifier power connection. If one is	12 AWG is more than adequate for this purpose.
desired, we recommend the use of a 40A AGU fuse	To connect the remote turn-on wire to the
or MaxiFuse™ type.	amplifier, first back out the set screw on the top of		1) Input Voltage Range: A wide range of signal
	the amplifier, using the supplied hex wrench. Strip	input voltages can be accommodated by the
	1/2 inch (12mm) of wire and insert the bare wire	300/2's input section (200mV – 8V).This wide
	into the receptacle on the front panel of the	range is split up into two sub-ranges, accessible via
	amplifier, seating it firmly so that no bare wire is	a switch located in the “Amplifier Input Section”.
	exposed. When using smaller wire, it may be		The “Low” position on the “Input Voltage”
	necessary to strip 1 inch of insulation from the wire	switch selects an input sensitivity range between
	and fold the bare wire in half prior to insertion.	200mV and 2V.This means that the “Input Sens.”
	While holding the wire in the terminal, tighten the	rotary control will operate within that voltage
	set screw firmly, taking care not to strip the head of	window. If you are using an aftermarket source unit,
	the screw and making sure that the wire is firmly	with conventional preamp-level outputs, this is most
	gripped by the set screw.	likely the position that you will use.
			The “High” position on the “Input Voltage”
		switch selects an input sensitivity range between
		800mV and 8V.This is useful for certain high-output
		preamp level signals as well as speaker-level output
		from source units and small amplifiers.To use
		speaker-level sources, splice the speaker output
		wires of the source unit or small amplifier onto a
		pair of RCA plugs.
			!	IMPORTANT
			The output of the amplifier will decrease for a
		given input voltage when the “Input Range” switch
		is placed in the “High” position. Conversely, the
		output will be higher with the switch in the “Low”
		position. While this may sound counter-intuitive, it is
		consistent with the descriptions above.

2)Input Sensitivity Adjustment: Located next to the “Input Voltage” switch in the “Amplifier Input Section” nput section is a rotary control labeled

“Input Sens.”. Once the appropriate “Input Voltage” range has been selected, this control can be used to match the source unit's output voltage to the input stage of the 300/2 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.)

To properly set the amplifier for maximum clean output, please refer to Appendix B (page 13) in this manual. After using this procedure, you can then adjust the “Input Sens.” level downward if this is required to achieve the desired system balance.

Do not increase the “Input Sens.” setting for any amplifier in the system beyond the maximum level established during the procedure outlined in Appendix B (page 13). Doing so will result in audible distortion and possible speaker damage.

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