JL Audio G2250 Owners Manual

OWNER’S MANUAL

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!

Left & Right

Preamp Inp ut Jacks

(pg. 6)

Protectio n Status

Indicator

(pg. 9)

Left & Right

Preamp Out put Jacks

(pg. 8)

Input Voltage

Selection

(pg. 6)

Power Statu s

Indicator

(pg. 9)

Bass EQ

On/Off Switc h

(pg. 8)

Jack for
Remote Bass
Control K nob

(pg. 8)

Filter Mode

Selection

(pg. 7)

Filter

Frequenc y Selector

(pg. 7)

Input Sensitiv ity

Control

(pg. 6)

Remote Turn-On

Connector

(pg. 6)

Chassis Ground

Connector

(pg. 5)

+12 V Power

Connector

(pg. 5)

Speaker Outputs

(pg. 8)

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

2 JL AUDIO G2250 JL AUDIO G2250 3

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

PRODUCT DESCRIPTION

The JL Audio G2250 is a two-channel
full-range audio amplifier utilizing patented
Absolute Symmetry™ Class A/B technology for
both channels.

The G2250 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 power wire (minimum 8 AWG) 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 4 AWG
or larger power wire and a power distribution
block if additional amplifiers are being
installed with the G2250.

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 of the JL Audio ECS master
ground lug, XB-MGLU is recommended).
Use the same size power wire as the wire

connected to the “+12 VD C” connection

(minimum 8 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.

8) Connect the positive and negative power

wires to the amplifier. A fuse near the
amplifier is not necessary.

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 (25A for a

single G2250) 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 G2250’s “+12V DC ” and “Ground”

connections are designed to accept 8 AWG -
4 AWG power wire. 8 AWG is a minimum power

wire size for this amplifier.

If you are installing the G2250 with other
amplifiers and wish to use a single main power
wire, use 4 AWG or larger main power wire
(depending on the overall current demands of all
the amplifiers in the system). This 4 AWG or
larger power wire should terminate into a
distribution block mounted as close to the
amplifiers as possible and should connect to the
G2250 with 8 AWG - 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 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
place, tighten the set screw firmly, taking care not
to strip the head of the screw.

The ground connection should be made using
the same gauge wire as the power connection
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 G2250 is being run from that power wire,
we recommend a 25A fuse be used. AFS (mini
blade fuse), AGU (big glass fuse) or MaxiFuse™
(big plastic-body fuse) types are recommended.

No fuse is required or recommended directly
before the amplifier power connection. If one is
desired, we recommend the use of a 25A.

TURNON LEAD

The G2250 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 G2250’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 set screw.

4 JL AUDIO G2250 JL AUDIO G2250 5

INPUT SECTION

The G2250’s input section allows you to send
signals to the amplifier section through the
use of two differential-balanced inputs, one for
the left channel and one for the right channel.
Connection is via RCA-type jacks.

Input Voltage Range:

A wide range of signal input voltages can be
accommodated by the G2250’s input section
(200mV – 8V). This wide range is split up into
two sub-ranges, accessible via a switch located to
the left of the Input Connectors.

The “Low” position on the “Input Voltage”

switch selects an input sensitivity range between

200mV and 2V. This means that the “Input
Sens.” rotary control will operate within that

voltage window. If you are using an aftermarket
source unit or an OEM interface processor with
conventional preamp-level outputs, this is most
likely the position that you will use.

The “High” position on the “Input Voltage”
switch selects an input sensitivity range between
800mV and 8V. This is useful for certain high­output preamp level signals as well as speaker­level output from source units and
small amplifiers.

To use speaker-level sources, splice the speaker
output wires of the source unit or small amplifier
onto a pair of RCA plugs. No line output
converter is needed in most cases.

The output of the amplifier will decrease for
a given input voltage when the “Input Range”
switch is placed in the “High” position.
Conversely, the output will be higher with the
switch in the “Low” position. While this may
sound counter-intuitive, it is consistent with the
descriptions above.

INPUT SENSITIVITY CONTROL

Once the appropriate “Input Voltage” range
has been selected, the control labeled “Input
Sens.” located in the “Amplifier Controls”
section 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 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.

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 mid­range 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 the G2250 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” Control: The G2250 employs a

12dB per octave filter which can be configured
into one of two filter types or defeated
completely by way of the three-position “Filter
Mode” switch:
“O ff ”: Defeats the filter completely, allowing
the full range of frequencies present at the
inputs to feed the amplifier. This is useful for
systems utilizing outboard crossovers or
requiring full-range reproduction from the
G2250’s channels.
“LP ” (L ow-Pa ss): Configures the filter to
attenuate frequencies above the selected filter
frequency at a rate of 12dB per octave. This is
useful for connection of subwoofer(s) to the
G2250’s in a bi-amplified system.
“HP” (High-Pass): Configures the filter to
attenuate frequencies below the selected filter
frequency at a rate of 12dB per octave. This is
useful for connection of component speakers to
the G2250’s channels in a bi-amplified system.

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

markings surrounding this rotar y control
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 13).

Tuning Hint: If you are using the G2250 to drive
a subwoofer system (“LP” mode) or 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 12), you
can f ine tune the “Filter Freq. (Hz)” control to
achieve the desired system frequency response.

6 JL AUDIO G2250 JL AUDIO G2250 7