JL Audio XD500/3 Owners Manual

OWNER’S MANUAL

500W 3-Channel Amplier

Thank you for purchasing a JL Audio amplifier for

your automotive sound system.

Your amplifier has been designed and manufactured to exacting

standards in order to ensure years of musical enjoyment in your vehicle.

For maximum performance, we highly recommend that you have

your new amplifier installed by an authorized JL Audio dealer. Your

authorized dealer has the training, expertise and installation equipment

to ensure optimum performance from this product. Should you

decide to install the amplifier yourself, please take the time

to read this manual thoroughly so as to familiarize yourself

with its installation requirements and setup procedures.

If you have any questions regarding the instructions in this

manual or any aspect of your amplifier’s operation, please contact your

authorized JL Audio dealer for assistance. If you need further assistance,

please call the JL Audio Technical Support Department

at [phone] during business hours.

PROTECT YOUR HEARING!

We value you as a long-term customer. For
that reason, we urge you to practice restraint in
the operation of this product so as not to damage
your hearing and that of others in your vehicle.
Studies have shown that continuous exposure to
high sound pressure levels can lead to permanent
(irreparable) hearing loss. This and all other
high-power amplifiers are capable of producing
such high sound pressure levels when connected
to a speaker system. Please limit your continuous
exposure to high volume levels.

While driving, operate your audio system in
a manner that still allows you to hear necessary
noises to operate your vehicle safely (horns,
sirens, etc.).

SERIAL NUMBER

In the event that your amplifier requires
service or is ever stolen, you will need to have
a record of the product’s serial number. Please
take the time to enter that number in the space
provided below. The serial number can be found
on the bottom panel of the amplifier and on the
amplifier packaging.

Serial Number:

INSTALLATION APPLICATIONS

This amplifier is designed for operation in
vehicles with 12 volt, negative-ground electrical
systems. Use of this product in vehicles with
positive ground and/or voltages other than 12V
may result in damage to the product and will void
the w arra nty.

This product is not certified or approved for
use in aircraft.

Do not attempt to “ bridge” the outputs of this
amplifier with the outputs of a second amplifier,
including an identical one.

2 | JL Audio - XD500/3 Owner’s Manual

Input

Mode
Switch
(pg. 7)

Preout

Selector

(pg. 7)

Remote

Level Mode

Switch
(pg. 9)

(pg. 11)

Status

LED

Ch. 1 & 2

Filter Mode

Selection

(pg. 8)

Ch. 1 & 2 Filter

Frequency

Ch. 1 & 2 Input

Sensitivity Control

(pg. 7)

Selector

(pg. 8)

Sub. Ch.

Filter Mode

Selection

(pg. 8)

Sub. Ch. Input

Sensitivity Control

(pg. 7)

Sub. Ch. Input

Sensitivity Control

(pg. 7)

PLANNING YOUR INSTALLATION

IMPORTANT

!

It is important that you take the time to read
this manual and that you plan out your
installation carefully. The following are some
considerations that you must take into account
when planning your installation.

Cooling Efficiency Considerations:

The outer shell of your JL Audio amplifier is
designed to remove heat from the amplifier
circuitry. For optimum cooling performance, this
outer shell should be exposed to as large a volume
of air as possible. Enclosing the amplifier in a
small, poorly ventilated chamber can lead to
excessive heat build-up and degraded
performance. If an installation calls for an
enclosure around the amplifier, we recommend
that this enclosure be ventilated with the aid
of a fan. In normal applications, fan-cooling
is not necessary.

Mounting the amplifier upside down is
strongly discouraged. If mounting the amplifier
under a seat, make sure there is at least 1 inch
(2.5 cm) of space above the amplifier’s outer
shell to permit proper cooling.

Safety Considerations:

Your amplifier needs to be installed in a dry,
well-ventilated environment and in a manner
which does not interfere with your vehicle’s safety
equipment (air bags, seat belt systems, ABS brake
systems, etc.). You should also take the time to
securely mount the amplifier so that it does not
come loose in the event of a collision or a sudden
jolt to the vehicle.

Stupid Mistakes to Avoid

• Check before drilling any holes in your vehicle

to make sure that you will not be drilling
through a gas tank, brake line, wiring harness or
other vital vehicle system.

• Do not run system wiring outside or underneath

the vehicle. This is an extremely dangerous
practice which can result in severe damage to
your vehicle and person.

• Protect all system wires from sharp metal

edges and wear by carefully routing them,
tying them down and using grommets and
loom where appropriate.

• Do not mount the amplifier in the engine

compartment, under the vehicle, on the roof
or in any other area that will expose the
amplifier circuitry to the elements.

ENGLISH

+12 V Power

Connector

Chassis Ground

Connector

(pg. 5)

Remote Turn-On

Connector

(pg. 5)

+12 VDC Ground Remote

(pg. 6)

Channels 1 & 2

Preamp Input Jacks

(pg. 7)

Subwoofer Ch.

Preamp Input Jacks

(L)

(R)

CH. 1& 2 SUB CH. Preouts

INPUT SECTION

(pg. 7)

Preout

Jacks

(pg. 7)

Jack for
Remote Level
Control Knob

(pg. 9)

Remote

Level

Control

Channels 1 & 2

Speaker Outputs

(pg. 10)

CH. 1

CH. 2

(L)

(R)

Bridged Mono Subwoofer Output

Subwoofer Outputs

Mono

(pg. 10)

3

PRODUCT DESCRIPTION

The JL Audio XD500/3 is a three-channel,
system amplifier utilizing JL Audio NexD™ ultra­high speed switching technolog y for its two main
channels and NexD™ high-speed switching for
its subwoofer channel. The NexD™ technologies
deliver outstanding fidelity and efficiency.

The XD500/3 can be operated with a wide
variety of source units and system configurations.

TYPICAL INSTALLATION SEQUENCE

The following represents the sequence
for a typical amplifier installation, using an
aftermarket source unit or OEM Interface
processor (like the CleanSweep CL441dsp).
Additional steps and different procedures may
be required in some applications. If you have
any questions, please contact your authorized
JL Audio dealer for assistance.

1) Disconnect the negative battery post

connection and secure the disconnected cable
to prevent accidental re-connection during
installation. This step is not optional.

2) Run 4 AWG power wire from the battery

location to the amplifier mounting location.
Take care to route the wire in such a way that
it will not be damaged and will not interfere
with vehicle operation. Use 2 AWG or larger
power wire and a power distribution block if
additional amplifiers are being installed with
the XD500/3.

3) Connect power wire to the positive battery

post. Fuse the wire with an appropriate fuse
block (and connectors) within 18 inches (45
cm) wire length of the positive battery post.

This fuse is essential to protect the vehicle.
Do not install the fuse until the power wire
has been securely connected to the amplifier.

4) Run signal cables and remote turn-on wire

from the source unit to the final amplifier
mounting location.

5) Run speaker cables from the speaker systems

to the amplifier mounting location.

6) Find a good, solid metal grounding point

close to the amplifier and connect the
negative power wire to it using appropriate
hardware (use of the JL Audio ECS master
ground lug, XB-MGLU is recommended).
Use 4 AWG wire, no longer than 36 inches
(90 cm) from the amplifier to the ground
connection point. In some vehicles, it may
be necessary to upgrade the battery ground
wire. (See page 5 for important notice).

7) Securely mount the amplifier.

8) Connect the positive and negative power

wires to the amplifier. A fuse near
the amplifier is not necessary if the
XD500/3 is the only device being run
from the fused main power wire. If
the fused main power wire is shared
by the XD500/3 and other amplifiers
or devices, fuse each amplifier/device
within 12 inches (30 cm) of wire length,
via a fused distribution block or multiple
individual fuse blocks/on-board fuses.

9) Connect the remote turn-on wire

to the amplifier.

10) Connect the input cables to the amplifier.

11) Connect the speaker cables to the amplifier.

12) Carefully review the amplifier’s control

settings to make sure that they are set
according to the needs of the system.

13) Install the power wire fuse(s) (50A for a

single XD500/3) and reconnect the negative
battery post terminal.

14) Turn on the source unit at a low level

to double-check that the amplifier is
configured correctly. Resist the temptation
to crank it up until you have verified the
control settings.

15) Make necessary adjustments to the input

sensitivity controls to obtain the right
overall output and the desired balance
in the system. See Appendix A (page 14)
for the recommended input sensitivity
setting method.

16) Enjoy the fruits of your labor with your

favorite music.

4 | JL Audio - XD500/3 Owner’s Manual

POWER CONNECTIONS

INPUT SECTION

Remote

Level

Control

CH. 1& 2 SUB CH. Preouts

CH. 1

(L)

CH. 2

(R)

Bridged Mono Subwoofer Output

IMPORTANT

!

Before installing the amplifier, disconnect the
negative (ground) wire from the vehicle’s battery.
This will prevent accidental damage to the system,
the vehicle and your body during installation.

(L)

+12 VDC Ground Remote

(R)

The XD500/3’s “+12 VDC” and “Ground”
connections are designed to accept 4 AWG
power wire. 4 AWG is the required wire size for

this amplifier.

If you are installing the XD500/3 with other
amplifiers and wish to use a single main power
wire, use 2 AWG or 1/0 AWG main power wire
(depending on the overall current demands of all
the amplifiers in the system). This large power
wire should terminate into a fused distribution
block mounted as close to the amplifiers as
possible (within 12 inches / 30cm of wire length).
The fused output of the distribution block will
connect to the XD500/3 with 4 AWG power
wire. JL Audio ECS fused distribution blocks are
recommended (XD-FDBU-2 and XD-FDBU-4)

Note: Smaller AWG numbers mean bigger
wire and vice-versa (1/0 AWG is the largest, 2
AWG is smaller, then 4 AWG, then 8 AWG, etc.).

To connect the power wires to the amplifier,
first back out the set screw on the top of the
terminal block, using the supplied 2.5 mm hex
wrench. Strip 1/2 inch (12 mm) of insulation from
the end of each wire and insert the bare wire into
the terminal block, seating it firmly so that no
bare wire is exposed. 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 (not the insulation) is firmly
gripped by the wire clamp in the terminal.

The ground connection should be made
using 4 AWG wire and should be kept as short
as possible, while accessing a solid piece of sheet
metal in the vehicle. The surface of the sheet
metal should be sanded at the contact point
to create a clean, metal-to-metal connection
between the chassis and the termination of
the ground wire. For optimal grounding, we
recommend the use of a JL Audio ECS master
ground lug (XB-MGLU). Alternatively, a sheet
metal screw or bolt can be used with a star
washer.

Any wires run through metal barriers (such
as firewalls), must be protected with a high
quality rubber grommet to prevent damage to the
insulation of the wire. Failure to do so may result
in a dangerous short circuit.

Many vehicles employ small (10 AWG -
6 AWG) wire to ground the battery to the
vehicle chassis and to connect the alternator's
positive connection to the battery. To prevent
voltage drops, these wires should be upgraded
to 4 AWG when installing amplifier systems
with main fuse ratings above 60A.

FUSE REQUIREMENTS

It is absolutely vital that the main power
wire(s) to the amplifier(s) in the system be
fused within 18 inches (45 cm) of the positive
battery post connection. The fuse value at each
power wire should be high enough for all of the
equipment being run from that power wire. If
only the XD500/3 is being run from that power
wire, we recommend a 50A fuse be used.

If fusing the amplifier near its power
connections (when more than one amp is being
run from the main power wire), use a 50A fuse.
MAXI™ plastic-body fuses are recommended.

ENGLISH

5

TURNON LEAD

INPUT SECTION

Remote

Level

Control

CH. 1& 2 SUB CH. Preouts

CH. 1

(L)

CH. 2

(R)

Bridged Mono Subwoofer Output

Remote

Level

Control

CH. 1

(L)

CH. 2

(R)

Bridged Mono Subwoofer Output

The XD500/3 uses a conventional +12V remote
turn-on lead, typically controlled by the source
unit's remote turn-on output. 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.

The XD500/3’s “Remote” turn-on connector
is designed to accept 18 AWG – 12 AWG wire. To
connect the remote turn-on wire to the amplifier,
first back out the set screw on the top of the
terminal block, using the supplied 2.5mm hex
wrench. Strip 1/2 inch (12mm) of wire and insert
the bare wire into the terminal block, seating it
firmly so that no bare wire is exposed. 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 (not the
insulation) is firmly gripped by the wire clamp in
the terminal.

(L)

+12 VDC Ground Remote

(R)

INPUT SECTION

The M500/3’s input section allows you to send
signals to the amplifier section through the use
of two or four differential-balanced inputs.

Input connections are via one or two pairs of
traditional RCA-type jacks.

(L)

(R)

Remote

CH. 1& 2 SUB CH. Preouts

INPUT SECTION

If you wish to send four discrete channels into
the XD500/3, simply use all four inputs and set
the “Input Mode” switch in the “4 Ch.” position.
The amplifier will automatically combine the Sub
Ch. input signals to mono.

You may also choose to apply only two
channels of input to deliver signal to all three
amplifier channels. To do this, set the “Input
Mode” switch to “2 Ch.” and use only the
inputs to channels 1 & 2. The amplifier will
automatically combine the Ch. 1 & 2 input
signals to mono for the Subwoofer Channel.

6 | JL Audio - XD500/3 Owner’s Manual

Input Voltage Range:

The XD500/3’s input sections are designed to
accept signal voltages from 100mV – 4V. This
will accommodate all preamp level signals and
many speaker level signals.

To use speaker-level sources, simply splice the
speaker output wires of the source unit onto a
pair of RCA plugs for each input pair. (or use
JL Audio part XD-CLRAIC2-SW) No “line
output converter” is needed in most cases.

If you find that the output cannot be reduced
sufficiently with a direct speaker level signal
applied to the amplifier, you may use a “line
output converter” to reduce the signal level.

INPUT SENSITIVITY CONTROLS

The controls labeled “Input Sens.” located in

each channel section can be used to match the
source unit’s output voltage to the input stage of
each group 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 counter­clockwise 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

14) in this manual. After using this procedure,
you can then adjust any or all “Input Sens.”
levels downward if this is required to achieve the
desired system balance.

ENGLISH

Do not increase any “Input Sens.” setting for
any channel(s) of any amplifier in the system
beyond the maximum level established during
the procedure outlined in Appendix A (page 14).
Doing so will result in audible distortion and
possible speaker damage.

7

FILTER CONTROLS

Most speakers are not designed to reproduce
the full range of frequencies audible by the human
ear. For this reason, most speaker systems are
comprised of multiple speakers, each dedicated
to reproducing a specific frequency range. Filters
are used to select which frequency range is sent to
each section of a speaker system. The division of
frequency ranges to different speakers can be done
with passive filters (coils and/or capacitors between
the amplifier outputs and the speakers), which
are acceptable and commonly used for filtering
between mid-range speakers and tweeters. Filtering
between subwoofer systems and satellite speaker
systems is best done with active filters, which cut
off frequency content at the input to the amplifier.
Active filters are more stable than passive filters
and do not introduce extraneous resistance, which
can degrade subwoofer performance.

The active filter built into each channel section
of the XD500/3 can be used to eliminate
potentially harmful and/or undesired frequencies
from making their way through the amplifier
sections to the speaker(s). This serves to improve
tonal balance and to avoid distortion and possible
speaker failure. Correct use of these filters can
substantially increase the longevity and fidelity of
your audio system.

1) “Filter Mode” Controls: The XD500/3

employs a 12dB per octave high-pass filter for
its main channels. The Subwoofer Channel
employs a low-pass filter with the option of
12dB or 24dB / octave slopes. Each of these
filters can be controlled or defeated completely
by way of the “Filter Mode” switch in each
Channel Section:

Channel 1 & 2 Filter: 2dB/octave High-Pass only

“Off”: Defeats the filter completely, allowing
the full range of frequencies present at the
inputs to feed these channels. This is useful for
systems utilizing outboard active crossovers
or requiring full-range reproduction for this
channel pair.
“HP” (High-Pass): Configures the filter
to attenuate frequencies below the indicated
filter frequency at a rate of 12dB per octave.
This is useful for connection of component
speakers or coaxials to this channel pair in a
bi-amplified system.

Subwoofer Channel Filter: 12dB/octave
or 24dB / octave, Low-Pass only

“Off”: Defeats the filter completely, allowing

the full range of frequencies present at the
inputs to feed this channel. This is useful for
systems utilizing outboard active crossovers.

“12dB” (Low-Pass): Configures the filter

to attenuate frequencies above the indicated
filter frequency at a rate of 12dB per octave.
This is useful for connection of subwoofers
in a bi-amplified system. This shallower slope
gently attenuates high-frequencies from your
subwoofer signal and is often well-suited for
sedans and coupes with trunks.

“24d B” (Low-Pass): Configures the filter

to attenuate frequencies above the indicated
filter frequency at a rate of 24dB per octave.
This is useful for connection of subwoofers
in a bi-amplified system. This sharper slope
more aggressively removes high-frequencies
from your subwoofer signal and is often well­suited for SUV’s, wagons and hatchbacks.

2) “Filter Freq. (Hz)” The filter frequency

markings surrounding these rotary controls
(one in each Channel Section) are for
reference purposes and are generally accurate
to within 1/3 octave or better. If you would
like to select the filter cutoff frequency with a
higher level of precision, consult the chart in
Appendix B (page 15).

8 | JL Audio - XD500/3 Owner’s Manual

Tuning Hint: If you are using the XD500/3

CH. 1

(L)

CH. 2

(R)

Bridged Mono Subwoofer Output

to drive a subwoofer system (“LP” mode),
and a component satellite speaker system
(“HP” mode), 80 Hz is a good baseline
“Filter Freq. (Hz)” setting. After properly
adjusting the “Input Sens.”, as outlined in
Appendix A (page 14), you can fine tune
the “Filter Freq. (Hz)” control to achieve
the desired system frequency response.

REMOTE LEVEL CONTROL OPTIONAL

Remote

Level

Control

With the addition of the optional Remote
Level Control (HD-RLC), you can control the
volume of the subwoofer channel (Subwoofer
Level) or of the entire XD500/3 from the front of
the vehicle (Master Volume).

The HD-RLC connects to the jack labeled
“Remote Level Control” on the Connection Panel
of the amplifier using a standard telephone cable
(supplied with the HD-RLC). If desired, multiple
XD (and HD) amplifiers can be controlled from
a single HD-RLC controller using a simple phone
line “splitter” and multiple phone cables.

When connected to the amplifier, the
HD-RLC operates as follows. At full counter­clockwise rotation, the audio of the selected
channels will mute completely. At full clockwise
rotation the level will be the same as if the
HD-RLC was not connected at all. In other
words, it operates strictly as a level attenuator.

“Remote Level Mode” Switch: This switch
allows you to assign the operation of the
HD-RLC to the entire amplifier or only the
subwoofer channel. In the “A ll ” position, the
HD-RLC knob will affect all channels equally.
In the “Sub Ch.” position, only the level of
the subwoofer channel will be affected by the
HD-RLC knob.

PREOUTS

The XD500/3 incorporates a pass-through
preamp output section, so that additional
amplifiers can be easily added to the system. This
pass-through pre-amp output can be configured
three different ways using the switch labeled
“Preouts From”.

1) “1&2”: The preamp output delivers the same

signal that is connected to the CH 1&2 Inputs.

2) “Sub”: The preamp output delivers the same

signal that is connected to the Subwoofer
Channel Inputs.

3) “Sum”: The preamp output delivers a summed

signal, combining the “Ch 1 & 2” inputs and the

“Sub Ch.” inputs into a stereo signal pair.

Note: Any signal delay between the “Ch 1 & 2”

and “Sub Ch.” inputs can result in a cancellation
of signals within certain frequency ranges when
using the “Sum” position. If you experience a loss
of bass output in the “Sum” position, compared
to the “1&2” position, you are likely dealing
with a delayed signal in either the front or rear
outputs of the source unit. If the front to rear delay
is desirable for other reasons or if it cannot be
defeated at the source unit, we recommend that
you use the “1&2” position.

ENGLISH

Note: In any of the three modes, the preamp
output signal is not affected by any crossover
filter selected (if the input signal is full-range, the
preamp output will be full-range).

9

SPEAKER OUTPUTS

IMPORTANT

!

IMPORTANT

!

IMPORTANT

!

The XD500/3’s speaker outputs are designed
to accept 16 AWG - 8 AWG wire. To connect the
speaker wires to the amplifier, first back out the
set screws on the top of the terminal block, using
the supplied 2.5 mm hex wrench. Strip 1/2 inch
(12 mm) of insulation from the end of each wire
and insert the bare wire into the terminal block,
seating it firmly so that no bare wire is exposed.
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
(not the insulation) is firmly gripped by the wire
clamp in the terminal.

The XD500/3’s main channels are designed to
deliver power into speaker loads equal to or greater
than 2 ohms when using a “stereo” configuration
and speaker loads equal to or greater than 4
ohms when using a “bridged ” configuration. The
subwoofer channel is designed to deliver power into
subwoofer loads equal to or greater than 2 ohms.

CH. 1

(L)

CH. 2

(R)

Bridged Mono Subwoofer Output

Speaker loads below 2 ohms nominal per
channel (or 4 ohms bridged) are not
recommended and may cause the amplifier
to initiate a protection mode which reduces
power output.

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 XD500/3 has been designed
for bridging of its main channel pair without the
need for input inversion adaptors.

To bridge the main channels, use the “Left +”
and “Right –” speaker connectors only (the “Left
–” and “Right +” remain unused). The bridged
channel pair will deliver optimum power into a 4
ohm load.

When the XD500/3’s main channels are
bridged, they will deliver 200W x 1 into a 4
ohm load or 150W x 1 into an 8 ohm load.
Operating the bridged channels into a load
lower than 4 ohms is not recommended.

A bridged pair of channels requires that both
channels in the pair receive input. You must
connect the mono or stereo source signal to
both the left and right inputs of the bridged
channel pair. Connection of only one input will
result in reduced power output, increased
distortion and can cause the amplifier to
overheat. Do not do this!

When the XD500/3’s main channels are
operating in bridged mode, the output will be in
mono (only one channel). This mono channel can
contain only right channel information, only left
channel information, or the sum of the signals
from right and left input channels. In order to
achieve one of these options, configure the inputs
to that pair of channels in one of these two ways:

10 | JL Audio - XD500/3 Owner’s Manual

1) Left Channel Only or Right Channel Only

IMPORTANT

!

Information: If you wish to send a left-only
or right-only signal to the XD500/3’s main
channels you must use a “Y-Adaptor” to split

the single channel signal into both left and
right RCA inputs of the bridged channel
pair. This option is used when deploying the

XD500/3’s main channels to drive left channel
speakers only or right channel speakers only.

2) Left + Right Channel Information: When

bridged and fed by a stereo source signal, the
XD500/3’s main channels will automatically
combine the left and right input signals into a
summed mono (left + right) input signal. This
can be useful to drive a center speaker.

SUBWOOFER OUTPUTS

The XD500/3’s single subwoofer channel is
designed to deliver power into subwoofer loads
equal to or greater than 2 ohms. It is rated for
300W into 2 ohms, 250W into 3 ohms and 200W
into 4 ohms (Continuous Power, RMS Method).

Subwoofer loads below 2 ohms nominal are not
recommended and may cause the amplifier
to initiate a protection mode which reduces
power output.

The XD500/3’s subwoofer outputs are designed
to accept 16 AWG - 8 AWG wire. To connect the
subwoofer wires to the amplifier, first back out
the set screws on the top of the terminal block,
using the supplied 2.5 mm hex wrench. Strip
1/2 inch (12 mm) of insulation from the end
of each wire and insert the bare wire into the
terminal block, seating it firmly so that no bare
wire is exposed. 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 (not the insulation) is firmly
gripped by the wire clamp in the terminal.

ENGLISH

CH. 1

(L)

CH. 2

(R)

Bridged Mono Subwoofer Output

You will notice that there are two “+” positive
connections and two “–” negative connections.
This is to facilitate multiple subwoofer wiring.

The two positive and two negative connections
are connected in parallel inside the amplifier
They are not stereo outputs. Connecting two

subwoofers, each to one set of positive and
negative terminals, will result in a parallel
subwoofer connection. If only connecting one
pair of subwoofer wires, it is not necessary to use
both sets of connections.

11

STATUS LED / PROTECTION CIRCUITRY

There is a single multi-color LED on the top
surface of the amplifier to indicate the amplifier’s
operating status.



1) Flashing Green: amplifier is powering up,
audio output is muted.

2) Constant Green: amplifier is on and
functioning normally, audio output is active.

3) Constant Red: Indicates that the amplifier has
exceeded its safe operating temperature, putting
the amplifier into a self-protection mode, which
reduces the peak power output of the amplifier.
When its temperature returns to a safe level, the
red light will return to green and the amplifier
will return to full-power operating mode.

5) LED off / Amplifier Shuts Off Unexpectedly

The only condition that will shut down
an undamaged XD500/3 completely is if battery
voltage or remote turn-on voltage drops below
10 volts. The “Status LED” will turn off when
this occurs. The amplifier will turn back on
when voltage climbs back 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 D (pages 16, 17).

4) Constant Amber (yellow): Indicates that
an over-current condition has occurred and
is accompanied by a muting of the affected
channel(s). Because the muting behavior may be
very short in duration, it may manifest itself as
an audible, repetitive ticking 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 short­circuit 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. The “Status LED”
will remain amber for a few seconds, even if the
over-current condition is of a very short duration.
This functionality can be used to diagnose a
short-circuit by only connecting one channel at
a time. The “Status LED” will turn amber when
you connect the channel that is experiencing the
problem and turn the volume up.

12 | JL Audio - XD500/3 Owner’s Manual