Filter
Top Products
SERVICING YOUR 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
JL AUDIO 300/2 11
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).
10 JL AUDIO 300/2