JL Audio JD 400/4 Owner's Manual page 11

right (CH. 2&4) RCA inputs. This option
is useful when using a pair of the JD400/4's
channels to drive left channel speakers only
and the other pair of the JD400/4's channels to
drive right channel speakers only.
2) Left + Right Channel Information:
When bridged and fed by a stereo input, a pair
of the JD400/4's channels will automatically
combine the left and right channels into a
summed mono (left + right) channel. This
option is useful when using a pair of the
JD400/4's channels to drive a subwoofer system
or a summed mono center channel.
STATUS LEDS / PROTECTION CIRCUITRY
JD amplifiers are equipped with separate
Status and Protection LEDs on the top surface of
the amplifier to indicate the amplifier's
operating condition.
Status LED
Constant Blue: The amplifier is on.
Protection LED
1) Constant Red: Lights to indicate that the
amplifier has exceeded its safe operating
temperature, putting the amplifier into
a self-protection mode, which mutes the
power output of the amplifier. When its
temperature returns to a safe level, this LED
will turn off and the amplifier will return to
normal operating mode.
JD400/4
2) Flashing/Constant Red: The Protection
LED also illuminates during over-current
conditions. This may result in the LED
flashing as it corresponds to peaks in
242 mm
music volume. Extended over-current
9.50 in
conditions will cause the LED to illuminate
continuously. During these events, the
amplifier's output will be muted. Because
the muting behavior may be very short in
duration, it may manifest itself as an audible,
repetitive ticking or thumping noise in the
output. Over-current conditions can be
caused by a speaker impedance lower than
the optimum load impedance range for the
amplifier or a short-circuit in the speaker
wiring. The latter can result from a short
circuit between the positive and negative
speaker wires or between either speaker
wire and the vehicle chassis.
All LEDs Off / Amplifier Shuts Off
Unexpectedly:
The only condition that will shut down an
undamaged JD amplifier completely is if battery
voltage or remote turn-on voltage drops below
10 volts. When this occurs, both LEDs will turn
off. The amplifier will turn back on when voltage
climbs above 11 volts. If this is happening in your
system, have your charging system and power
wiring inspected.
For more information on troubleshooting this
amplifier, refer to Appendix C (pages 16, 17).
190 mm
7.50 in
214 mm
8.40 in
11