JL Audio J2500.1 - Manual (Page 4)

6 JL Audio® 7
“inPut sensitiVitY” (gain) adJustment
Located next to the input connectors is a rotary
control labeled “Input Sens.”. This rotary control
can be used to match the source unit’s output
voltage to the input stage of the amplifier for
maximum clean output.
Reversed | Normal
Output Polarity
LP Filter Frequency (Hz) Input Sens. Bass Boost
min max 40 130 Off +12dB
Power
Remote
Level
Port
LEFT
RIGHT
LEFT
RIGHT
Preamp
Outputs
Amplifier
Inputs
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
A (page 12) in this manual. After using this
procedure, you can then adjust the level of the
amplifier by adjusting the input sensitivity
downward, if the amplifier requires attenuation 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 A (page 12). Doing so will result in
audible distortion and possible speaker damage.
“lP Filter” (CrossoVer) Control
The J2-500.1 employs a 12dB/octave low-pass
(LP) active filter for its internal channel. This
feature is designed to attenuate frequencies above
its filter frequency, so that the system’s subwoofers
do not reproduce any audible midrange content.
The low-pass filter in the J2-500.1 is fully
variable between 40 Hz and 130 Hz via the “LP
Filter Frequency” control knob. The 12 o’clock
position corresponds to 80 Hz, and is a good
starting point for system tuning.
Reversed | Normal
Output Polarity
LP Filter Frequency (Hz) Input Sens. Bass Boost
min max 40 130 Off +12dB
Power
Remote
Level
Port
LEFT
RIGHT
LEFT
RIGHT
Preamp
Outputs
Amplifier
Inputs
“outPut PolaritY” Control
The J2-500.1 includes a switch to quickly reverse
the polarity of its audio output. This is very useful
for establishing a smooth transition between the
subwoofers and main speaker systems. Choose
the position that results in the strongest midbass
and the best “up-front” bass presence.
Reversed | Normal
Output Polarity
LP Filter Frequency (Hz) Input Sens. Bass Boost
min max 40 130 Off +12dB
Power
Remote
Level
Port
LEFT
RIGHT
LEFT
RIGHT
Preamp
Outputs
Amplifier
Inputs
“remote” turn-on
The J2-500.1 is turned on and off
using a conventional +12V remote turn-
on lead, typically controlled by the
source unit’s remote turn-on output.
Made in China
Speaker Output (Mono) FUSES + 12VDC
15A 15A 15A 15A
Remote Ground
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.
“amPliFier inPuts”
The J2-500.1 only offers low-level (preamp
level) input connections via a single pair of RCA-
type jacks that are compatible with a wide range
of aftermarket source units and processors. If you
wish to use speaker level signals, you will need to
employ a line-output converter (not included).
Reversed | Normal
Output Polarity
LP Filter Frequency (Hz) Input Sens. Bass Boost
min max 40 130 Off +12dB
Power
Remote
Level
Port
LEFT
RIGHT
LEFT
RIGHT
Preamp
Outputs
Amplifier
Inputs
You may run a stereo or a mono signal into
the inputs of the amplifier. The amplifier’s input
section automatically sums stereo signals to mono
for the internal amplifier section.
The amplifier will operate with only one
input connection (left or right), but will require
an increase in input sensitivity to overcome the
loss of signal. If a mono input signal is to be run
into the RCA jacks, we recommend that you use
a “Y-adaptor” to split the mono signal into both
the Left and Right inputs of the amplifier.
If you plan to use the preamp outputs to feed a
stereo amplifier, you must connect a stereo
signal to the input of the amplifier. A mono
signal into the amplifier will result in a mono
signal out of the preamp output.
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