Turn-On Lead; Crossover Controls - JL Audio 300/4v2 Owner's Manual

TURN-ON LEAD

The 300/4v2 uses a conventional +12V remote
turn-on lead, typically controlled by the source
unit's remote turn-on output. The amplifier will
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.
Remote
designed to accept 18 AWG – 8 AWG wire.
12 AWG is more than adequate for this purpose.
To connect the remote turn-on wire to the
amplifier, first back out the set screw on the top
of the amplifier, using the supplied hex wrench.
Strip 1/2 inch (12mm) of wire and insert the
bare wire into the receptacle on the front panel
of the amplifier, seating it firmly so that no bare
wire is exposed. When using smaller wire, it may
be necessary to strip 1 inch of insulation from
the wire and fold the bare wire in half prior to
insertion. While holding the wire in the terminal,
tighten the set screw firmly, taking care not to
strip the head of the screw and making sure that
the wire is firmly gripped by the set screw.
FRONT AND REAR INPUT SECTIONS
The 300/4v2 has two separate input sections,
one for its front channels and another for its rear
channels. Each section contains a pair of RCA-
Input Voltage
Input Sens.
Front Input Section Rear Input Section
Input Voltage Input Sens. Input Mode Input Voltage Input Sens.
Low | High 2ch | 4ch Low | High
Left Ch. Right Ch. Left Ch. Right Ch.
Front Input Section
Input Mode
four amplifier channels with one or two pairs of
input signals.
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1) Input Mode Switch: If you wish to operate
all four channels of the 300/4v2 with a single
2ch
Input Mode
single pair of input cables to the input jacks
Front Input Section
the amplifier will route the signals connected
to the front inputs to the rear inputs as well.
If you wish to use separate inputs for the front
and rear channel sections (to allow front-to-
rear fading, for example) and the source unit
is equipped with front and rear outputs, select
4ch Input Mode
mode, you must connect separate pairs of input
cables to each input section.
2) Input Voltage Range: A wide range of signal
input voltages can be accommodated by each of
the 300/4v2's input sections (200mV – 8V).
This wide range is split up into two sub-ranges,
accessible via switches located in each input
section of the amplifier. Be aware that each
Input Voltage
have to be configured, regardless of how many
input cables are actually feeding the amplifier.
Low Input Voltage
switch selects an input sensitivity range
between 200mV and 2V. This means that the
Input Sens
within that voltage window. If you are using an
aftermarket source unit, with conventional
preamp-level outputs, this is most likely the
High
Input Voltage
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 for each input pair or use
the JL Audio ECS Speaker Wire to RCA
adaptor (XB-CLRAIC2-SW).
!
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
correct as described.
3) Input Sensitivity Adjustment: Located next
Input Voltage
Input
Sens. Input Voltage
range has been selected, this control 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). To properly set each pair
of amplifier channels for maximum clean
output, please refer to Appendix A (page 14)
in this manual. After using this procedure,
you can then adjust the relative level of each
channel pair by adjusting the input sensitivity
downward on either or both channel pairs, if
they require attenuation to achieve the desired
Input
Sens.
beyond the maximum level established during
the procedure outlined in Appendix A (page
and possible speaker damage. Be aware that
Input Sens.
be made, regardless of how many input cables
are feeding the amplifier. These controls will
allow you to set the appropriate relative levels
for front and rear channels and any other
amplifier channels in the system.

CROSSOVER CONTROLS

Crossovers are groups of individual electronic
filters which allow only certain frequency
ranges to pass through them by attenuating
frequencies outside the selected range. These
filters allow the user to specify what frequency
range will be sent out of each channel section
of the amplifier. This, in turn, allows each
speaker system to only reproduce a range of
frequencies it is well-suited for, resulting in
reduced distortion and improved fidelity.
Front And Rear Filter Section:
Front Filter Controls Rear Filter Controls
Freq. Range Filter Slope Freq. Range Filter Slope
x1 | x10 12dB | 24dB x1 | x10 12dB | 24dB
95 95
Filter Mode Filter Mode
75 130 75 130
60 200 60 200
Off | LP | HP Off | LP | HP
50 500 50 500
Filter Freq. (Hz) Filter Freq. (Hz)
The 300/4v2 employs two separate, but
identical filter sections for its front and rear
channel pairs. These sections consist of the
following controls
1) Filter Mode
to configure the filter into one of two filter
types or to defeat it completely:
Off
section completely, allowing the full range of
frequencies present at the inputs to feed that
pair of channels. This is useful for systems
range reproduction from that pair of channels.
LP
attenuate frequencies above the selected
filter frequency. Useful for connection of
subwoofer(s) to that channel section.
HP
attenuate frequencies below the selected
filter frequency. Useful for connection
of component speakers to that channel
section in a bi-amplified system.
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