JL Audio J2320.4 User Manual

OWNER’S MANUAL

320W 4-Channel, Full-Range Amplifier

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.

2 JL Audio

3

PROTECT YOUR HEARING!

HP | Off | LP
Filter Mode

High-PassLow-Pass

Filter Frequency (Hz)

Filter Frequency (Hz)

Input Sens.

Input Sens.

CH 3&4

Input From

min maxmin max 60 1. 2k

High-Pass

60 1. 2k 40 15 0

Low-Pass

40 15 0

Off +12dB

High-Level InputsHigh-Level Inputs

Bass Boost

HP | Off | LP
Filter Mode

1&2 | 3&4

Off +12dB

Bass Boost

Channel 3 & 4 Controls

CH 1 (Left) CH 3 (Left)

Protect

Channel 1 & 2 Controls

Power

CH 2 (Right)

LEFT

RIGHT CH 4 (Right)

Pre-Outs Amplifier Inputs

Protectio n Status

Indicator

(pg. 11)

Low-Pass Filter

Frequenc y Control

(pg. 8)

Input Sensitiv ity

Control

(pg. 7)

Input Sensitiv ity

Control

(pg. 7)

Filter Mode

Selector

(pg. 8)

Filter Mode

Selector

(pg. 8)

Channel Input

Selector

(pg. 7)

Left & Right

Pream p Output Jacks

(pg. 9)

High-Level

Input Jack

(pg. 6,7)

Power Stat us

Indicator

(pg. 11)

Bass Boost

Control

(pg. 9)

Bass Boost

Control

(pg. 9)

High Leve l
Input Jack

(pg. 6,7)

High-Pass Filter

Frequenc y Control

(pg. 8)

High-Pass Filter

Frequenc y Control

(pg. 8)

Low-Pass Filter

Frequenc y Control

(pg. 8)

CH 1 & CH 2

Preamp Inp ut Jacks

(pg. 6)

CH 3 & CH 4

Preamp Inp ut Jacks

(pg. 6)

Remote Turn-On

Connector

(pg. 6)

CH 1 & CH 2

Speaker Outputs

(pg. 9)

CH 3 & CH 4

Speaker Outputs

(pg. 9)

+12 V Power

Connector

(pg. 5)

Fuses

(pg. 5)

Chassis Ground

Connector

(pg. 5)

Made in China

CHANNEL 1 (L) CHANNEL 2 (R)

Bridged Bridged

CHANNEL 3 (L) CHANNEL 4 (R) FUSES

30A30A

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
th e w ar ran ty.

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 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.

4 JL Audio

5

Remote

30A30A

Remote

PRODUCT DESCRIPTION

The JL Audio J2-320.4 is a four-channel, full­range audio amplifier utilizing
Class B technology for all channels.

The J2-320.4 can be operated with a wide
variety of source units and system configurations.
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 4 AWG 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. Use 2 AWG or larger
power wire and a power distribution block if
additional amplifiers are being installed with
the J2 -320.4.

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 amplif ier and connect the
negative power wire to it using appropriate
hardware. Use the same size power wire as the

wire connected to the “+12 VD C” connection

(minimum 4 AWG), 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 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 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 (60A for a

single J2-320.4) 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 body during installation.

The J2-320.4’s “+12V DC ” and “Ground”
connections are designed to accept 4 AWG power
wire. 4 AWG is a minimum power wire size for

this amplifier.

If you are installing the J2-320.4 with other
amplifiers and wish to use a single main power
wire, use 2 AWG or larger main power wire
(depending on the overall current demands of all
the amplifiers in the system). This 2 AWG or
larger power wire should terminate into a
distribution block mounted as close to the
amplifiers as possible and should connect to the
J2-320.4 with 4 AWG power wire.

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

J2-320.4. Use a Phillips screwdriver to secure the

wire via the screw on the top of each 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. The use of a star washer to
lock down the connection is advisable.

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 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

While the J2-320.4 has two 30A ATC fuses
on its power connection panel, these do nothing
to protect the vehicle from a dangerous short
circuit in the power wire. They only protect the
amplifier. It is absolutely vital that the main
power lead 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 J2-320.4 is being run from that power
wire, we recommend a 60A fuse be used. AFS or
MAXI-type fuses are recommended.

6 JL Audio

7

HP | Off | LP
Filter Mode

High-PassLow-Pass

Filter Frequency (Hz)

Input Sens.

Input Sens.

CH 3&4

Input From

min maxmin max 60 1.2k

Off +12dB

High-Level InputsHigh-Level Inputs

Bass Boost

1&2 | 3&4

Channel 3 & 4 Controls

CH 1 (Left) CH 3 (Left)

Protect

CH 2 (Right)

LEFT

RIGHT CH 4 (Right)

Pre-Outs Amplifier Inputs

HP | Off | LP
Filter Mode

High-PassLow-Pass

Filter Frequency (Hz)

Input Sens.

Input Sens.

CH 3&4

Input From

min maxmin max 60 1.2k

Off +12dB

High-Level InputsHigh-Level Inputs

Bass Boost

1&2 | 3&4

Channel 3 & 4 Controls

CH 1 (Left) CH 3 (Left)

Protect

CH 2 (Right)

LEFT

RIGHT CH 4 (Right)

Pre-Outs Amplifier Inputs

TURNON LEAD

Remote

HP | Off | LP
Filter Mode

High-PassLow-Pass

Filter Frequency (Hz)

Input Sens.

min maxmin max 60 1.2k

Off +12dB

High-Level InputsHigh-Level Inputs

Bass Boost

Channel 3 & 4 Controls

CH 1 (Left) CH 3 (Left)

Protect

CH 2 (Right)

HP | Off | LP
Filter Mode

High-PassLow-Pass

Filter Frequency (Hz)

Input Sens.

Input Sens.

CH 3&4

Input From

min maxmin max 60 1.2k

High-Pass

60 1.2k 40 15 0

Off +12dB

High-Level InputsHigh-Level Inputs

Bass Boost

1&2 | 3&4

Channel 3 & 4 Controls

CH 1 (Left) CH 3 (Left)

Protect

Channel 1 & 2 Controls

CH 2 (Right)

LEFT

RIGHT CH 4 (Right)

Pre-Outs Amplifier Inputs

The J2-320.4 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 amplif ier 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
1/2-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.

INPUT SECTIONS

The J2-320.4’s has two input sections: one for
Channels 1&2 and another for Channels 3&4.
These input sections allows you to send signals to
the amplifier sections through the use of either
two or four inputs. Each input section offers
two input connection methods, one for high­level (speaker level) signals and one for low-level
(preamp level) signa ls.

1) Low-Level Inputs: A standard left/

right pair of RCA type jacks in the
“Amplifier Inputs” section is used for
preamp level (low-level) signal input
on the J2-320.4. This is the preferred
connection method whenever available.

2) High-Level Inputs: If your system does

not offer a preamp level signal option, you
can connect speaker level signals directly to
the “High-Level Inputs” connectors using
the supplied mating connectors and wire
harnesses. Simply splice the appropriate
left/right and positive/negative wires to the
included harnesses and plug the harness into
the “High-Level Inputs” connectors on the
amplifier. The J2-320.4 will attenuate the high­level signals to make them compatible with its
input stages.

Make sure you observe correct polarity in
making the “High Level Input” connections.
Failure to do so will reduce bass and affect
stereo imaging.

The connections for the “Hig h Level Input s” plug
wires are a s follows from left to right on the plug:

Channels 1&2 (FRONT)

White: Left Positive (+)

White/Black: Left Negative (–)
Black: Common Ground (rarely used)*

Gray: Right Positive (+)

Gray/Black: Right Negative (–)

Channels 3&4 (REAR or SUB)

Green: Left Positive (+)

Green/Black: Left Negative (–)
Black: Common Ground (rarely used)*

Purple: Right Positive (+)
Purple/Black: Right Negative (–)

*The only time you will use the Common Ground
connections is with some older (pre-1980’s) factory
systems or head units that ground their speakers to
chassis ground. To use these connections, ground
the black wires on the plugs to chassis ground and

only connect the Left and Right Positive plug wires

to the factory radio outputs.

“CH 3&4 Input From” Switch

If you wish to send four discrete channels of
input into the J2-320.4, simply use all four inputs
(Channels 1 & 2 and Channels 3 & 4) and set the

“CH 3&4 Input From” switch to “3&4”.

If you wish to feed all four channels by using

only two channels of input, set the “CH 3&4
Input From” switch to “1&2 ” and use only the

inputs to channels 1 & 2.

INPUT SENSITIVITY CONTROLS

The controls labeled “Input Sens.” located in

each “Channel Controls” section can be used
to match the source unit’s output voltage to the
input stage of each pair 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
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 any or all “Input Sens.”

levels downward if this is required to achieve the
desired system balance.

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

12). Doing so will result in audible distortion
and possible speaker damage.