Audio Design JX1000-1D, JX500-1, JX250-1 User Manual

OWNER’S MANUAL

Monoblock Subwoofer Amplifiers

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 our Technical Support Department

at [phone] during business hours.

IMPORTANT

!

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.).

Chassis Ground

Connector

(pg. 5)

Power Status

Indicator

(pg. 11)

+12 V Power

Connector

(pg. 5)

Protection Status

Indicator

(pg. 11)

Remote Turn-On

Connector

(pg. 6)

Filter

Frequency Selector

(pg. 8)

Input Sensitivity

Control

(pg. 7)

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:

Speaker Outputs

(pg. 10)

High-Level

Input Jack

(pg. 6,7)

Preamp Input Jacks

Preamp Output Jacks

Left & Right

(pg. 6)

Left & Right

(pg. 8)

Remote

Level Control

(pg. 9)

Bass Boost

Control

(pg. 9)

INSTALLATION APPLICATIONS

This amplifier is designed for operation in
vehicles with 12V, 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.

PLANNING YOUR INSTALLATION

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 using appropriate
hardware 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

2 JL Audio JX250/1 • JX500/1 • JX1000/1D 3

IMPORTANT

!

PRODUCT DESCRIPTION

JL Audio JX monoblock subwoofer
amplifiers are specifically designed to drive
subwoofers. Their frequency response is
limited to the range below 150 Hz., making
them unsuitable for driving midrange speakers
or tweeters. For detailed specifications,
please refer to Appendix B (page 13).

TYPICAL INSTALLATION SEQUENCE

The following represents the sequence
for a typical amplifier installation, using an
aftermarket source unit or OEM Interface
product. 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 power wire from the battery location

to the amplifier mounting location,
taking care to route it in such a way
that it will not be damaged and will not
interfere with vehicle operation. See
next page for appropriate wire size.

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 connected to the amplifier.

4) Run signal cables (RCA cables) and remote

turn-on wire from the source unit to the
amplifier mounting location.

5) Run speaker wire 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 the same size power wire
used for the +12V connection, no longer
than 36 inches (90 cm) from the amplifier's
ground (GND) connector 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 using
appropriate hardware.

8) Connect the positive and negative power
wires to the amplifier.

9) Connect the remote turn-on wire
to the amplifier.

10) Connect the input cables
to the amplifier.

11) Connect the speaker wires 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 power wire fuse (see next page for
correct value) 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 12)
for the recommended input sensitivity
setting method.

16) Enjoy the fruits of your labor with your
favorite music.

POWER CONNECTIONS

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 person during installation.

The amplifier’s “+12 VDC” (positive) and
“Ground” (ground) connections are designed to
accept up to 4 AWG power wire.

Minimum Power / Ground

Wire Size Requirements:

JX250/1: 8 AWG
JX500/1: 4 AWG

JX1000/1D: 4 AWG

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.).

The above wire gauge recommendations
assume no other amplifiers are connected
to the same wire. Use larger wire with
a fused distribution block (or separate
wires) for multiple amplifiers.

If you are installing this amplifier 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 2 AWG
or 1/0 AWG power wire should terminate into a
fused distribution block mounted as close to the
amplifiers as possible and should connect to the
JX monoblock with 4 AWG power wire (8 AWG is
sufficient for the JX250/1 only).

To connect the power and ground wires
to the amplifier, strip 1/2-inch (12 mm) of
insulation from each wire and insert the
bare wire into the appropriate terminal block
positions on the JX250/1. Use the supplied

2.5 mm hex wrench to secure the wire via
the screw on the top of each terminal.

The “Ground” connection should be made
using 4 AWG wire (8 AWG is sufficient for
JX250/1 only) 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. The use of a #10 sheet metal screw
and star washer to lock down the connection is
advisable. Alternatively, you can use a specialized
grounding lug, such as the JL Audio XB-MGLU.
Any wires run through metal barriers (such
as firewalls), must be protected with a high
quality insulating 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 batter y. To prevent
voltage drops, these wires should be upgraded
to 4 AWG when installing amplifier systems
with main fuse ratings above 60A.

FUSE REQUIREMENTS

JX250/1: 30A (AGU or MAXI®)

JX500/1: 60A (AGU or MAXI®)

JX1000/1D: 80A (AGU, ANL or MAXI®)

An appropriate fuse at the main power wire(s)
to the amplifier(s) is vital for vehicle safety! This
fuse must be installed within 18 inches (45 cm)
of the positive battery post connection. If the JX
monoblock is the only device connected to this
main wire, use the corresponding fuse value listed
above (no other fuse is required in this situation).

When running multiple devices from one
main power wire, the main fuse value and rating
of the main power wire must be high enough
for all of the equipment being run from it. Use a
fused distribution block to split the main power
wire feed to each device, with appropriate fusing
and power wire for each device.

ENGLISH

4 JL Audio JX250/1 • JX500/1 • JX1000/1D 5

IMPORTANT

!

IMPORTANT

!

REMOTE TURNON

The JX monoblock amplifier is turned on
and off using 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 ignition­switched 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 1/2­inch (12 mm) of insulation from the wire and
insert it into the “Remote” receptacle on the
power connector. Tighten the connector down
using the supplied 2.5 mm hex wrench.

AMPLIFIER INPUTS

The JX monoblock amplifier offers
two input connection methods, one for
high-level (speaker level) signals and one
for low-level (preamp level) signals.

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. For this reason, when feeding a mono
input signal into the "Low-Level Inputs", use a
Y-adaptor splitter to split the mono signal and
connect it to both the Left and Right Low-Level
Inputs of the amplifier.
When feeding a mono signal to the "Hi-Level
Inputs", connect it in parallel to both left and
right input wires.

1) Low-Level Inputs: A standard left/

right pair of RCA type jacks is used for
preamp level (low-level) signal input on
the JX monoblocks. This is the preferred
connection method whenever available.

2) Hi-Level Inputs: If your system does not offer
a preamp level signal option, you can connect
speaker level signals directly to the “Hi-Level
Inputs” connector using the supplied mating
connector and wire harness. Simply splice the
appropriate left/right and positive/negative
wires to the included harness and plug the
harness into the “Hi-Level Inputs” connector
on the amplifier. The JX monoblock will
attenuate the high-level signal to make it
compatible with its input stage.

Make sure you observe correct polarity in
making the “Hi-Level Input” connections.
Failure to do so will result in a complete loss of
signal (no bass).

The connections for the “Hi-Level Inputs” plug wires
are as follows from left to right on the plug:

White: Left Positive (+)
White/Black: Left Negative (–)
Black: Common Ground (rarely used)*
Gray: Right Positive (+)
Gray/Black: Right Negative (–)

*The only time you will use the “Common
Ground” connection is with some older (pre-

1980’s) factory systems or head units that ground
their speakers to chassis ground. To use this
connection, ground the black wire on the plug to
chassis ground and only connect the Left and Right

Positive plug wires to the factory radio outputs.

If you plan to use the preamp outputs to feed a
stereo amplifier, you must connect stereo
signals to the inputs of the amplifier. A mono
signal into the amplifier will result in a mono
signal out of its preamp output.

“INPUT SENSITIVITY” GAIN ADJUSTMENT

Located to the left of 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.

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.

ENGLISH

6 JL Audio JX250/1 • JX500/1 • JX1000/1D 7

LOWPASS FILTER CONTROL

IMPORTANT

!

The JX monoblock employs a 12dB/octave
low-pass 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 mid-range content.

The low-pass filter is fully variable between
50 Hz and 200 Hz via the “Filter Frequency”
control knob. 80 Hz (as shown in the diagram
below) is a good starting point for system tuning.

“PREOUTS”

The JX monoblock incorporates a pass-

through preamp output (Preouts) section,

designed to make multiple amplifier systems
easy to set up. This section consists of a pair
of RCA-type jacks marked “Preouts”.

These preamp outputs deliver the same signal
that is being fed to the Low-Level inputs. (If the
input signals are full-range, the preamp outputs
will be full-range). This signal is not affected by
the bass boost or Filter processing selected for the
amplifier.

“BASS BOOST” CONTROL

The JX monoblock includes a single band,
boost-only bass equalizer controlled by a rotary
knob marked “Bass Boost”. This control has a
boost range of 0dB (full-counterclockwise) to
+12dB (full-clockwise) and is centered at 45 Hz.

REMOTE LEVEL CONTROL

With the optional RBC-1 Remote Level
Control (sold separately), you can control the
subwoofer volume from the front of the vehicle.

The RBC-1 connects to the jack
labeled “Remote Level Control” on the

Connection Panel of the JX Monoblock

amplifier, using a standard telephone
cable (supplied with the RBC-1).

When connected to the amplifier, the
Remote Level Control operates as follows.
At full counter-clockwise rotation, the audio
will mute completely. At full clockwise
rotation the level will be the same as if
the RBC-1 was not connected at all. In
other words, it operates strictly as a level

attenuator. This control will not affect the
"Bass Boost" feature of the JX Monoblock.

ENGLISH

The "Preouts" of the JX250/1 and JX500/1 will
not pass signals from the Hi-Level inputs. The
JX1000/1D will pass signals from the Hi-Level
inputs and will attenuate them to Low-Level.

8 JL Audio JX250/1 • JX500/1 • JX1000/1D 9

Care should be taken to securely mount this
control in a manner that does not interfere with
vehicle operation.

When setting the amplifier’s input sensitivity,
the Remote Level Control should be unplugged or
at full clockwise rotation (maximum level).

SPEAKER OUTPUT

IMPORTANT

!

IMPORTANT

!

IMPORTANT

!

Subwoofer connection to the JX monoblock
is straightforward and takes place at the
far right of the power/speaker connection
panel. Two positive (“+”) connections and
two negative (“–”) connections are available
via a connector labeled “Speaker Output
(Mono)”. The dual connections allow for two
separate speaker wire runs to be parallel­connected to the amplifier’s mono output.

Speaker loads below 2Ω nominal are not
recommended and will cause the amplifier to
enter into a protection mode.

Do not chassis ground any speakers connected
to this or any other JL Audio amplifier. Doing so
will cause the amplifier to go into protection.

To connect the speaker wires to the amplifier,
strip 1/2-inch (12 mm) of insulation from each
speaker wire and insert them into their
appropriate connector (observing correct
polarity). Then, tighten each connector using the
supplied 2.5 mm hex wrench.

Do NOT attempt to “bridge” two JX
monoblocks together or combine their output
to a single load in any manner. Doing so will
damage the amplifier(s).

Before reconnecting the battery ground and
turning the system on, verify that all control
settings on the amplifier are set according to
the needs of the system.

STATUS INDICATOR LIGHTS /
PROTECTION CIRCUITRY

There are two status indicator lights on the

amplifier’s control panel. These are as follows:

1) “Power” (Green): Located at the far left of the
amplifier’s control panel, this LED lights to
indicate that the amplifier is turned on and
operating normally.

2) “Protect” (Red): Indicates that the amplifier
protection circuitry has been activated
to prevent product failure due to thermal
overload, short-circuit or a dangerously
low impedance connected to the amplifier
outputs. Connecting the speaker output to
an impedance lower than 2 ohms will cause
this protection mode to activate. When this
protection mode is activated, the amplifier will
shut down to protect its circuitry. When the
problem is corrected, the amplifier will return
to normal operation and the “Protect” LED
will shut off.

SERVICING YOUR 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 technical support.

JL Audio Technical Support:

[phone]

9:00 AM – 5:30 PM (Eastern Time Zone)

Monday - Friday

ENGLISH

10 JL Audio JX250/1 • JX500/1 • JX1000/1D 11