A1800
monoblock subwoofer amplifier
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 and extended warranty
coverage, 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 (954) 443-1100 during business hours.
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PROTECT YOUR HEARING!
INSTALLATION APPLICATIONS
PLANNING YOUR INSTALLATION
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.
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 warranty.
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.
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.
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.
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.
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 the supplied
screws so that it does not come loose in the event
of a collision or a sudden jolt to the vehicle.
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.
Stupid Mistakes to Avoid
Chassis Ground
Connector
(pg. 5)
• 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.
Speaker Outputs
(pg. 8)
+12 V Power
Connector
(pg. 5)
Remote Turn-On
Connector
(pg. 6)
• 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.
Serial Number:
• Protect all system wires from sharp metal
edges and wear by carefully routing them,
tying them down and using grommets and
loom where appropriate.
Input Voltage
Selection
(pg. 6)
Left & Right
Preamp Output Jacks
(pg. 8)
Protection Status
Indicator
Bass EQ
On/Off Switch
(pg. 8)
Filter Mode
Selection
(pg. 7)
(pg. 9)
Jack for
Left & Right
Preamp Input Jacks
(pg. 6)
Power Status
Indicator
(pg. 9)
Remote Bass
Control Knob
(pg. 8)
Input Sensitivity
Control
(pg. 6)
Filter
Frequency Selector
(pg. 7)
• 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.
CH 1 (Left)
Pre-Outs
Bass Boost Controls
Bass Boost
Filter Freq. (Hz)
65
Input Voltage
Input Sens.
LP Filter
55
45
40
80
100
200
Power
Protect
|
Low High
Remote
Bass Port
CH 2 (Right)
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JL AUDIO A1800
JL AUDIO A1800
3
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PRODUCT DESCRIPTION
POWER CONNECTIONS
The JL Audio A1800 is a monoblock subwoofer
amplifier utilizing proprietary and patented
Class D technology. Its frequency response
is limited to the range below 250 Hz. It is not
designed for driving midrange speakers or
tweeters. Every aspect of its operation has been
optimized for low-frequency amplification.
For detailed specifications, please refer to
Appendix C (page 13).
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, XA-MGL-1 is recommended).
Use the same size power wire as the wire
connected to the “+12VDC” connection
(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).
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 ground connection should be made using
the same gauge wire as the power connection (4
AWG) 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 (XA-MGL-1).
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.
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.
7) Securely mount the amplifier using the
supplied screws.
8) Connect the positive and negative power
wires to the amplifier. A fuse near the
amplifier is not necessary.
The A1800’s “+12VDC” 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 A1800 with other
amplifiers and wish to use a single main power
wire, use 2 AWG or larger main power wire for
systems with total power between 700W and
1400W or 1/0 AWG wire for systems with more
than 1400W. This main power wire should
terminate into a distribution block mounted as
close to the amplifiers as possible. The output of
the distribution block will connect to the A1800
with 4 AWG power wire.
9) Connect the remote turn-on wire
to the amplifier.
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 4 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
2 AWG or 1/0 AWG power wire and a power
distribution block if additional amplifiers are
being installed with the A1800.
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.
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.
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 (80A for a
single A1800) 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.
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 A1800 is being run from that power wire,
we recommend a 80A fuse be used. ANL (big
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 80A AGU,
AFS or MaxiFuse™ type.
Note: that 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.
16) Enjoy the fruits of your labor with your
favorite music.
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JL AUDIO A1800
JL AUDIO A1800
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TURN-ON LEAD
AMPLIFIER CONTROLS
The A1800 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 A1800’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 2.5 mm 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 is firmly
gripped by the set screw.
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. If a
mono input signal is to be run, we recommend
that you use a “Y-adaptor” to split the mono
signal into both inputs of the amplifier.
1) “Input Sens.”: 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.)
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 the A1800 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.
The A1800 employs a sophisticated, variable,
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
midrange content.
INPUT VOLTAGE RANGE:
A wide range of signal input voltages can be
accommodated by the A1800’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.
Filter Freq. (Hz)
65
Input Sens.
LP Filter
55
45
40
80
100
200
INPUT SECTION
The A1800’s input section allows you to send
signal to the amplifier section through the use
of two differential-balanced inputs, one for the
left channel signal and one for the right channel
signal. Connection is via RCA-type jacks.
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.
The “High” position on the “Input Voltage”
switch selects an input sensitivity range between
800mV and 8V. This is useful for certain high-
output preamp level signals as well as speaker-
level output from source units and
small amplifiers.
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.
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.
CH 1 (Left)
Input Voltage
|
Low High
2) Filter Operation: The low-pass filter in the
A1800 is fully variable between 40 Hz and
200 Hz via the “Filter Freq.” control knob
and features the ability to select between a
moderate “12dB” per octave or a steep “24dB”
per octave slope via the “Mode/Slope” switch.
Depending on the subwoofer system and
the vehicle, different slopes may be required
to produce a smooth transition to the mid-
bass speakers in the system. Experiment to
find the slope which best matches the acoustic
requirements of your system.
CH 2 (Right)
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.
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JL AUDIO A1800
JL AUDIO A1800
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BASS BOOST CONTROLS
Tuning Hint: A trunk mounted sub whose
output has to “fight” through a rear deck or a
back seat often benefits from the 12 dB/octave
slope which lets more upper bass content pass
through. A sub that fires directly into the
listening environment is more likely to benefit
from a 24 dB/octave slope.
The preamp output signal is not affected by the
“Bass Boost” processing selected for the amplifier
or by any crossover filter selected (if the input
signal is full-range, the preamp output will be
full-range).
The signal level of the “Preamp Output” is
line-level (low voltage), regardless of the position
selected via the A1800’s “Input Voltage” switch.
An additional amplifier connected to these
preamp outputs should have its input voltage
switch set to the “Low” position.
Speaker loads below 2 ohms nominal are not
recommended and may cause the amplifier
to initiate a protection mode which reduces
power output.
Bass Boost Controls
Bass Boost
Protect
You will notice that there are two “+” positive
connections and two “–” negative connections.
This is to facilitate multiple speaker wiring.
The two positive and two negative connections
are connected in parallel inside the amplifier.
Connecting two speakers, each to one set of
positive and negative terminals, will result in a
parallel speaker connection. If only connecting
one pair of speaker wires, it is not necessary to
use both sets of connections.
Remote
Bass Port
Note: The above hint is not “set-in-stone”… You
should always listen to the system carefully to
determine the best choice as vehicle acoustics and
other factors play a big role in choosing the most
appropriate filter slope.
1) “Bass Boost”: This switch allows the user
to activate a 6 dB boost centered at 48 Hz.
The “Filter Mode” switch in the “Amplifier
Controls” section must be in the “LP” position
for the bass boost to be functional.
3) Precise Frequency Selection: The filter
frequency markings on the front panel of
the amplifier are for reference purposes and
are generally accurate to within 1/3 octave
or better. If you would like to select the filter
frequency with a higher level of precision,
consult Appendix B (page 13) of this manual.
This chart gives you a more accurate frequency
for each of the forty detented positions of the
frequency selection control. This method can
be very useful if the amplifier is mounted in
a location where you can’t see the front panel
markings easily.
If you plan to use the “Pre-Outs” to feed
a stereo amplifier, you must connect a
stereo signal to the input of the amplifier.
A mono signal into the amplifier will result
in a mono signal out of the preamp output.
2) “Remote Bass Port”: This port allows you to
connect an optional remote boost knob (sold
separately, JL Audio Model RBC-1) that can
be mounted in the front of the vehicle. With
the RBC-1 connected, the boost is no longer
limited to 0 or +6 dB, allowing a range of
0 - 12 dB of boost to be selected.
SPEAKER OUTPUTS
The A1800’s speaker outputs are designed to
accept 16 AWG - 8 AWG wire.
The A1800 is designed to deliver power into
speaker loads equal to or greater than 2 ohms.
To connect the speaker wires to the amplifier,
first back out the set screws own 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.
PRE-OUTS
The A1800 incorporates a pass-through
preamp output section, so that additional
amplifiers can be easily added to the system.
The preamp output delivers the same signal that
is connected to the A1800’s inputs.
4) Defeating the Amplifier Filter: The Low-
Pass filter can also be defeated completely,
by switching the “Mode/Slope” switch to
the “Off” position. This is useful if you are
using an external active crossover in the
system. Keep in mind that turning the internal
crossover off also defeats the “Bass Boost”
processing (see next section for details). With
the internal crossover turned off, the A1800’s
upper frequency response limit is 250 Hz, due
to its bass-specific Class D design.
CH 1 (Left)
Pre-Outs
Power
CH 2 (Right)
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JL AUDIO A1800
JL AUDIO A1800
9
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AMPLIFIER STATUS INDICATOR LIGHTS &
PROTECTION CIRCUITRY
There are two status indicator lights on the
input / control end of the amplifier.
SERVICING YOUR JL AUDIO 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.
Low-Voltage protection:
If the car’s supply voltage drops below 10
volts, the entire amplifier will shut itself off to
protect its internal circuitry. The green “Power”
indicator will turn off when this occurs. The
amplifier will turn back on when voltage climbs
back above 10 volts. This may happen in a rapid
cycle when bass-heavy program material causes
a weak charging system to dip below 10 volts
momentarily. If this is happening in your system,
turn your audio system off and have your power
wiring, ground connections and charging
system inspected.
Power
Protect
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.
1) “Power” (Green): lights to indicate that the
amplifier is turned on and operating normally.
JL Audio Technical Support:
(954) 443-1100
9:00 AM – 5:30 PM (Eastern Time Zone)
Monday - Friday
2) “Protect” (Red): Indicates that the amplifier
protection circuitry has been activated to
prevent product failure due to a short-circuit or
a dangerously low impedance connected to the
amplifier output(s). Connecting the speaker
outputs to an impedance lower than 2 ohms
will cause this protection mode to activate.
When this protection mode is activated, the
amplifier will reduce it maximum power
output to protect its circuitry, which will
manifest itself as increased distortion. When
the problem is corrected, the amplifier will
return to normal operation.
Advanced Rollback Thermal protection
Unlike conventional thermal protection
systems, which shut down an amplifier when it
overheats, this system protects the amplifier by
gradually reducing power output if the amplifier’s
safe operating temperature is exceeded. The
amplifier will continue to operate and return
to normal power output once its temperature
returns to a normal range.
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JL AUDIO A1800
JL AUDIO A1800
11
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APPENDIX A:
APPENDIX B:
APPENDIX C:
Input Sensitivity Level Setting
8) Increase the “Input Sens.” control until the
target voltage is observed with the voltmeter.
9) Once you have adjusted the A1800 to its
maximum low-distortion output level,
reconnect the speaker(s). The “Input Sens.”
controls can now be adjusted downward if the
amplifier requires attenuation to achieve the
desired system balance.
Precise Frequency Selection Chart
A1800 Specifications
Following the directions below will allow the
installer to adjust the input sensitivity of each
amplifier channel pair simply and easily in just a
few minutes using equipment which is commonly
available in installation bays.
“FILTER FREQ” AMP FILTER
General Specifications:
Recommended Fuse Value: 80A
Detent
Number
Panel
Marking
Actual
Freq.
Recommended Fuse Type: AGU, AFS, ANL or MaxiFuse™
Full counter-clockwise: 42
01 . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
02 . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
03 . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
04 . . . . . . . . . . . “40” . . . . . . . . . . . .42
05 . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
06 . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
07 . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
08 . . . . . . . . . . . “45” . . . . . . . . . . . .47
09 . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
10 . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
11. . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
12 . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
13 . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
14 . . . . . . . . . . . “55” . . . . . . . . . . . .57
15 . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
16 . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
17 . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
18 . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
19 . . . . . . . . . . . “65” . . . . . . . . . . . .67
20 . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
21 . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
22 . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
23 . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
24 . . . . . . . . . . . “80” . . . . . . . . . . . .83
25 . . . . . . . . . . . . . . . . . . . . . . . . . . . .87
26 . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
27 . . . . . . . . . . . . . . . . . . . . . . . . . . . .96
28 . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
29 . . . . . . . . . . .“100” . . . . . . . . . . 108
30 . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
31 . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
32 . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
33 . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
34 . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
35 . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
36 . . . . . . . . . . .“200” . . . . . . . . . . 193
37 . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
38 . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
39 . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Full-clockwise: 198
Input Sections:
No. of Inputs: One Stereo Pair
Necessary Equipment
• Digital AC Voltmeter
Input Type: Differential-balanced with RCA jack inputs
Input Range: Switchable from 200mV - 2V RMS to
800mV - 8V RMS
• CD with a sine-wave test tone recorded at
0 dB reference level in the frequency range
to be amplified for that set of channels
(50 Hz for subwoofer channels, 1 kHz for a
midrange application). Do not use attenuated
test tones (-10 dB, -20 dB, etc.).
Do not increase any “Input Sens.” setting for
any amplifier channel or channel pair in the
system beyond the maximum level established
during this procedure. Doing so will result in
audible distortion and possible speaker damage.
Amplifier Section:
Amplifier Topology: H-Bridge, Class D Mono
with patented discrete drive circuitry
Power Supply: Unregulated MOSFET switching type
Rated Power at 12.5 V with less than
0.08% THD+Noise (20-250 Hz):
The Nine-Step Procedure
1) Disconnect the speaker(s) from the
It will be necessary to re-adjust the
“Input Sens.” for the affected channels if any
equalizer boost is activated after setting the
“Input Sens.” with this procedure. This applies
to any EQ boost circuit, including source unit
tone controls or EQ circuits. EQ cuts will not
require re-adjustment.
amplifier’s speaker output connectors.
2) Turn off all processing (bass/treble, loudness,
EQ, etc.) on the source unit, processors (if
used) and amplifier. Set fader control to center
position and subwoofer level control to 3/4 of
maximum (if used to feed the A1800).
3) Switch the “Input Voltage” switch to “Low”
and turn the “Input Sens.” control all the
way down.
4) Set the source unit volume to 3/4 of full
volume. This will allow for reasonable gain
overlap with moderate clipping at full volume.
5) Using the chart on this page, determine the target
voltage for input sensitivity adjustment according
to the nominal impedance of the speaker system
connected to the amplifier outputs.
6) Verify that you have disconnected the speakers
before proceeding. Play a track with an
appropriate sine wave (within the frequency
range to be amplified by the A1800) at 3/4
source unit volume.
7) Connect the AC voltmeter to the speaker output
connectors of the amplifier. Make sure you test
the voltage at the correct connectors (+ and –).
480W RMS x 1 @ 4 ohms, 800W RMS x 1 @ 2 ohms
Rated Power @ 14.4V with less than
1% THD + Noise (20-250 Hz):
640W RMS x 1 @ 4 ohms, 1000W RMS x 1 @ 2 ohms
Signal to Noise Ratio: >95 dB referred to rated power
(A-weighted, 20 Hz - 20 kHz noise bandwidth)
Frequency Response: 10 - 250 Hz (+0, -1 dB)
Damping Factor: >500 @ 4 ohms/50 Hz, >250 @ 2
ohms/50 Hz
Nom. Impedance
Target AC Voltage
43.8 V
4Ω
3Ω
2Ω
Amplifier Filter:
42.0 V
Amplifier Low-Pass Filter: State-variable, 12 dB/octave
Butterworth or 24 dB/octave Linkwitz-Riley with
continuously variable cutoff frequency selection
from 40 - 200 Hz. Defeatable.
40.0 V
Preamp Output:
Buffered pass-through type.
Dimensions(LxWxH):
15.75" x 9.25" x 2.50" (400mm x 235mm x 63.5mm)
Due to ongoing product development, all specifications are subject to
change without notice.
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JL AUDIO A1800
JL AUDIO A1800
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APPENDIX D: TROUBLE SHOOTING
“How do I properly set the input sensitivity on my amplifier”
“My amplifier shuts off once in a while, usually at higher volumes”
Check your voltage source and grounding point. The power supply
Please refer to Appendix A (page 12) to set the input sensitivity for
maximum, low-distortion output.
of the A1800 will operate with charging system voltages
down to 10V. Shutdown problems at higher volume levels
can occur when the charging system voltage drops below
10V. These dips can be of very short duration making them
extremely difficult to detect with a common DC voltmeter.
To ensure proper voltage, inspect all wiring and termination
points. It may also be necessary to upgrade the ground
wire connecting the battery to the vehicle’s chassis and the
power wire connecting the alternator to the battery. Many
vehicles employ small (10 AWG - 6 AWG) wire to ground the
battery to the vehicle’s chassis and to connect the alternator 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. Grounding problems are the
leading cause of misdiagnosed amplifier “failures.”
“My amplifier doesn’t turn on”
Check the fuse, not just visually, but with a continuity meter. It is
possible for a fuse to have poor internal connections that
cannot be found by visual inspection. It is best to take the
fuse out of the holder for testing. If no problem is found with
the fuse, inspect the fuse-holder.
Check the integrity of the connections made to each of the
“+12VDC”, “Ground”, and “Remote” terminals. Ensure
that no wire insulation is pinched by the terminal set screw
and that each connection is tight.
Check to make sure there is +12V at the “Remote” connection of the
amplifier. In some cases, the turn-on lead from the source unit
is insufficient to turn on multiple devices and the use of a relay
is required. To test for this problem, jump the “+12VDC” wire
to the “Remote” terminal to see if the amplifier turns on. If this
does not work, proceed to the next step.
“My amplifier turns on, but there is no output”
Check the input signal using an AC voltmeter to measure the
voltage from the source unit while an appropriate test tone is
played through the source unit (disconnect the input cables
from the amplifier prior to this test). The frequency used
should be in the range that is to be amplified by the amplifier
(example: 50 Hz for a sub bass application or 1 kHz for a full
range / high-pass application). A steady, sufficient voltage
(between 0.2 and 8.0-volts) should be present at the output of
the signal cables.
Check the output of the amplifier. Using the procedure explained in
the previous check item (after plugging the input cables back
into the amplifier) test for output at the speaker outputs of
the amplifier. Unless you enjoy test tones at high levels, it is
a good idea to remove the speaker wires from the amplifier
while doing this. Turn the volume up approximately half
way. 5V or more should be measured at the speaker outputs.
This output level can vary greatly between amplifiers but it
should not be in the millivolt range with the source unit at
half volume. If you are reading sufficient voltage, check your
speaker connections as explained below.
“I get a distorted / attenuated sound coming out of the speaker(s)”
Check the speaker wires for a possible short, either between the
positive and negative leads or between either speaker lead
and the vehicle’s chassis ground. If a short is present, you
will experience distorted and/or attenuated output. The
“Protect” light will illuminate in this situation. It may be
helpful to disconnect the speaker wires from the amplifier
and use a different set of wires connected to a test speaker.
Check the nominal load impedance to verify that of the amplifier is
driving a load equal to or greater than 2 ohms.
Check the input signal and input signal cables to make sure signal
is present at the “Amplifier Inputs” and the cables are not
pinched or loose. It may be helpful to try a different set of
cables and/or a different signal source to be sure.
“My amplifier’s output fluctuates when I tap on it or hit a bump”
Check the connections to the amplifier. Make sure that the
insulation for all wires has been stripped back far enough to
allow a good contact area inside the terminal block.
Check the input connectors to ensure that they all are making good
contact with the input jacks on the amplifier.
Check to ensure that the speaker wires are making a good
connection with the metal inside the terminal block. The
speaker wire connectors are designed to accept up to 8 AWG
wire. Make sure to strip the wire to allow for a sufficient
connection with the metal inside the terminal block.
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INSTALLATION NOTES:
Use this diagram to document your amplifier’s switch and control positions.
CH 1 (Left)
Pre-Outs
Bass Boost Controls
Filter Freq. (Hz)
65
Bass Boost
Input Voltage
Input Sens.
LP Filter
55
45
40
80
100
200
Power
Protect
|
Low High
Remote
Bass Port
CH 2 (Right)
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INSTALLATION NOTES:
INSTALLATION NOTES:
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JL AUDIO A1800
JL AUDIO A1800
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