OWNER'S MANUAL

H:J750/1
Monoblock Full-Range Amplifier

Thank you for purchasing a ]L 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 ofyour 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.
PROTECT YOUR HEARING! INSTALLATION APPLICATIONS
We value you as a long-term customer. For This amplifier is designed for operation in
that reason, we urge you to practice restraint in vehicles with 12V, negative-ground electrical
the operation of this product so as not to damage systems. Use of this product in vehicles with
your hearing and that of others in your vehicle. positive ground and/or voltages other than 12V
Studies have shown that continuous exposure to may result in damage to the product and will void
high sound pressure levels can lead to permanent the warranty.
(irreparable) hearing loss. This and all other This product is not certified or approved for
high-power amplifiers are capable of producing use in aircraft.
such high sound pressure levels when connected Do not attempt to "bridge" the outputs of this
to a speaker system. Please limit your continuous amplifier with the outputs of a second amplifier,
exposure to high volume levels. including an identical one.
While driving, operate your audio system in
a manner that still allows you to hear necessary PLANNING YOUR INSTALLATION
noises to operate your vehicle safely (horns, It is important that you take the time to read
sirens, etc.). this manual and that you plan out your
installation carefully. The following are some
SERIAL NUMBER considerations that you must take into account
In the event that your amplifier requires when planning your installation.
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:
Power Status Filter Slope
Indicator Selection
Ipgs.14·1S)
Filter Mode
Selection
j
(pg.1')
Filter Frequency
Selector
_____
j
/r====tlc========= ;;;;;;~~~1
(pg 10) - - - - (pg. 11) -

80 1"0
© I~~:; "I I~,~~:d.' 60.~OO
o
Status
Mode Slope Filter Freq. (Hz)

JL AUDIO. HD?

Chassis Ground Leh & Right

Connector Input Jacks

~~,r---
+ 12 V Power
Connector_
j
(pgs.6-7)
Remote Turn-On
_ Connector
j (pg.9) Jack for
Leh & Right Preamp Remote Level
_ Output Jacks _ Control Knob _ _
r=.-----===tl===::...:.:(
I
P9 S.6-7) (pgs.6-7) Ipg 12) (pg 13)

.~,~- '~~(;;;;;;;;l;;;;;;;;;;;;@ @~.. \

@ II[ POWER CONNECTOR II
r'
Inpu.. P,eou" Remote

@ ~ [~J R @ @ R C~~~~~,

2 I JL Audio - HD750/1 Owner's Manual

 Cooling Efficiency Considerations: Safety Considerations:
Your JL Audio amplifier employs an Your amplifier needs to be installed in a dry,
advanced type of heat management, called well-ventilated environment and in a manner
RealSink~. This feature takes advantage of which does not interfere with your vehicle's safety
convection and radiation effects to remove equipment (air bags, seat belt systems, ABS brake
heat from the amplifier circuitry. For optimum systems, etc.). You should also take the time to
cooling performance, the vertical heat sinks securely mount the amplifier using appropriate
located at the sides of the amplifier should be hardware so that it does not come loose in the
exposed to as large a volume of air as possible. event of a collision or a sudden jolt to the vehicle.
Enclosing the amplifier in a small, poorly
ventilated chamber can lead to excessive heat Stupid Mistakes to Avoid:
build-up and degraded performance. If an • Check before drilling any holes in your vehicle
installation calls for an enclosure around the to make sure that you will not be drilling
amplifier, we recommend that this enclosure through a gas tank, brake line, wiring harness or
be ventilated with the aid of a fan. In normal other vital vehicle system.
applications, fan-cooling is not necessary. • Do not run system wiring outside or underneath
If mounting the amplifier under a seat, the vehicle. This is an extremely dangerous
make sure there is at least 1 inch (2.5 em) of practice which can result in severe damage to
space above the amplifier's outer shell to permit your vehicle and person.
proper cooling. • Protect all system wires from sharp metal
edges and wear by carefuJIy 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
Input Sensitivity Output Polarity
Control Selection amplifier circuitry to the elements.
(pg. 10)
j
(pg. 11) Infrasonic Filter

~{II)
Input Voltage Selector
Selection (pg 1l) ---------...,rT-~
- -- (pg.9) -- ---

1 l~~~~~~
ILJ ILJ [U ©
lowlHigh 01180deg Off I 30Hz
Input
Sens.
Input
Voltage
Output
Polarity
Infrasonic
Filter o
)/1 Monoblock Amplifier

Speaker Outputs
(pgs. 13-14)

=====@======j==~=====1IH==~~\
o • 0 •
jI SPEAKER OUT I~ @
~amp@

3
PRODUCT DESCRIPTION
The JL Audio HD750/1 is a very powerful
and compact monoblock (single channel),
full-range amplifier utilizing patented Single
Cycle Control ~ Class D technology. This
groundbreaking technology delivers reference-
grade sonic performance while requiring
far less current from the vehicle's electrical
system than a conventional amplifier.
Unlike most monoblock amplifiers, the
HD750/1 is a full-range design, so it can be
used as a subwoofer amplifier or as a very
powerful full-range or satellite amplifier,
using a second 750/1 to form a stereo pair.
JL Audio's exclusive R.I.P.S. power supply
design optimizes the output the amplifier for any
impedance between 1.5 and 4 ohms, allowing
you to get full use of the HD750/l's performance
capabilities with a wide range of speaker systems.
The tightly regulated power supply design also
means that the HD750/l's clean power output
capability remains stable over a wide range of
vehicle voltages, resulting in enhanced fidelity.
A flexible input and crossover section permits
operation with a wide variety of source units
and system configurations. The HD750/l's
preamp output can send pass-through signals
from the inputs to feed additional amplifier(s).

4 I JL Audio - HD750/1 Owner's Manual

TYPICAL INSTALLATION SEQUENCE
The following represents the sequence for 7) Securely mount the amplifier using
a typical amplifier installation, using an appropriate hardware. (See page 8 for detailed
aftermarket source unit or OEM Interface mounting instructions).
processor (like the CleanSweep· CL441dsp). 8) Connect the remote turn-on wire and the
Additional steps and different procedures may positive and negative power wires to the
be required in some applications. If you have amplifier's power connector plug. Then insert
any questions, please contact your authorized the power connector plug into the amplifier's
JL Audio dealer for assistance. power connector receptacle, pushing firmly.
1) Disconnect the negative battery post 9) Connect the RCA input cables
connection and secure the disconnected cable to the amplifier.
to prevent accidental re-connection during 10) Connect the speaker wires to the speaker
installation. This step is not optional! connector plug and insert the plug firmly into
2) Run power wire from the battery location the speaker connector receptacle.
to the amplifier mounting location, taking 11) Carefully review the amplifier's control
care to route it in such a way that it will settings to make sure that they are set
not be damaged and will not interfere with according to the needs of the system.
vehicle operation. 4 AWG is recommended 12) Install power wire fuse (60A for a
for wire runs greater than 72 inches (180 single HD750/1) and reconnect the negative
em) in length. Use of 8 AWG power wire is battery post terminal.
acceptable for shorter runs, such as from a 13) Turn on the source unit at a low level
power distribution block to the amplifier or to double-check that the amplifier is
from a trunk-mounted battery. Use a 2 AWG configured correctly. Resist the temptation
or 1/0 AWG main power wire with a power to crank it up until you have verified the
distribution block when additional amplifiers control settings.
are being installed with the HD750/1 and 14) Make necessary adjustments to the input
powered from the same main power wire. sensitivity controls to obtain the right
3) Connect power wire to the positive battery overall output and the desired balance
post. Fuse the wire with an appropriate fuse in the system. See Appendix C (pages 18, 19)
block (and connectors) within 18 inches (45 for the recommended input sensitivity
em) wire length of the positive battery post. setting method.
This fuse is essential to protect the vehicle. 15) Enjoy the fruits of your labor with your
Do not install the fuse until the power wire favorite music.
has been connected to the amplifier.
4) Run signal cables (RCA cables) and remote
turn-on wire from the source unit or interface
processor to the amplifier mounting location.
5) Run speaker wire from the speaker systems to
the amplifier mounting location.
6) Find a good, solid, bale metal grounding
point close to the amplifier and connect the
negative power wire to it using appropriate
hardware. Use minimum 8 AWG power wire,
no longer than 36 inches (90 em) or 4 AWG
wire up to 60 inches (150 em) long from the
amplifier to the ground connection point. In
some vehicles, it may be (.. ?ssary to upgrade
the battery's ground wire as well. (See pages 6,
7 for important notice).

5
POWER AND TURN-ON CONNECTIONS
DIMPORTANTI
Before installing the amplifier, disconnect the We do not recommend the use of "copper-
negative (ground) wire from the vehicle's battery. clad aluminum wire" or "CCA" wire because
This will prevent accidental damage to the system, this wire is significantly less conductive than
the vehicle and your body during installation. pure copper wire. Only use pure copper power
wire, such as IL Audio's MetaWire'". Tinned

---~---------'(
copper wire (silver color) is acceptable as the
+12 VDC Ground Remote
tin-plating is only a very minor component of
the wire.
I !POWER CONNECTORJ I
Fuse Requirements

lrxxlJ The installation of a fuse on each power wire,

within 18 wire inches (45 cm) of the positive
battery terminal is vital to protect the wire and
the vehicle from fire in the event of a collision or
+12V Battery Connection short-circuit. The fuse value at each power wire
You will need to connect a power wire to should be high enough for all of the equipment
the vehicle's positive battery terminal, using an being run from that power wire. If only the
appropriate power ring or specialized battery HD750/1 is being run from that power wire, we
terminal connector, such as the ]L Audio recommend a 60A fuse be used. AGU (big glass
XB-BTU. This connection must be tight and fuse). AFS (small blade fuse) or MaxiFuse~ (big
corrosion-free to ensure proper connectivity. This plastic-body fuse) types are recommended. If
wire MUST be fused appropriately for safety. Any other amplifiers are also being powered from the
power wires run through metal barriers (such as wire and exceed 80 amps in total fuse rating, we
firewalls), must be protected with a high quality recommend the use of an ANL (large-blade) fuse
insulating grommet to prevent damage to the and holder. Please consult with your ]L Audio
insulation of the wire. Failure to do so may result dealer to make sure that the wire, fuse holder and
in a dangerous short circuit. fuse rating you have selected are appropriate for
your system's needs.
Power Wire Requirements No fuse is required or recommended directly
The HD750/l's "+12 VDC" and "Ground" before the amplifier power connection. If one is
connections are designed to accept 4 AWG power desired, use a 60A AGU, AFS or MaxiFuse'" type
wire. 4 AWG pure copper wire is recommended in an appropriate fuse block.
for any power wire run longer than 72 inches (180
em). For runs shorter than 72 inches, 8 AWG pure Ground Connection
copper power wire is acceptable. The chassis ground connection must be
If you are installing the HD750/1 with other made using 4 AWG or 8 AWG pure copper
amplifiers and wish to use a single main power wire and should be kept as short as possible,
wire, use 2 AWG or 1/0 AWG pure copper wire while accessing a solid piece of sheet metal
as a main power wire. This 2 AWG or 1/0 AWG in the vehicle. The surface of the sheet metal
power wire should terminate into a distribution should be sanded at the contact point to create
block mounted as close to the amplifiers as a clean, metal-to-metal connection between
possible and should connect to the HD7501I with the chassis and the termination of the ground
4 AWG or 8 AWG pure copper power wire. wire with a brass or copper power ring. For
Please note that lower AWG numbers mean optimal grounding, we recommend the
bigger wire and vice-versa (l/O AWG is the largest, use of a IL Audio ECS master ground lug
2 AWG is smaller, then 4 AWG, then 8 AWG, etc.). (XB-MGLU). Alternatively, a sheet metal
screw or bolt can be used with a star washer.

6 I JL Audio - HD750/1 Owner's Manual

DIMPORTANTI
Many vehicles employ small (10 AWG - 6 AWG) Amplifier Power Connector Plug
wire to ground the battery to the vehicle chassis To connect the power wires and the remote
and to connect the alternator's positive turn-on wire to the amplifier, unplug the power
connection to the battery. To prevent voltage connector plug from the amplifier chassis (pull
drops, these wires should be upgraded to 4 back firmly) and back out the set screws on
AWG pure copper wire when installing amplifier the connector plug, using the supplied 4 mm
systems with main fuse ratings above 60A. hex wrench for the "+12 VDC" and "Ground"
connections and the supplied 2.5 mm hex wrench
Turn-On Wire for the "Remote" connection. Strip 3/8 inch (10
The HD750!l uses a conventional +12V remote mm) of insulation from the end of each wire and
turn-on wire, typically controlled by the source insert the bare wire into the receptacle on power
unit's remote turn-on output. The amplifier will connector plug, seating it firmly so that no bare
turn on when +12V is present at its "Remote" wire is exposed. While holding each wire in place,
input and turn off when +12V is switched off. If tighten each set screw firmly, taking care not to
a source unit does not have a dedicated remote strip the head of the screw.
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 HD750/l's "Remote" turn-on connector
is designed to accept 18 AWG - 12 AWG wire. 18
AWG is more than adequate for this purpose.
To connect the remote turn-on wire to the
amplifier, first back out the set screw on the
bottom of the Power Connector Plug, using the
supplied 2.5 mm hex wrench. Strip 1/2 inch
(l2mm) of wire and insert the bare wire into the
receptacle, seating it firmly so that no bare wire
is exposed. When using smaller wire, it may DIMPORTANTI
be necessary to strip 1 inch of insulation from Never make power connections with a "live"
the wire and fold the bare wire in half prior to wire. Always disconnect the negative battery
insertion. While holding the wire in the terminal, post before making any connections or
tighten the set screw firmly using the supplied adjustments to a 12V power connection!
2.5 mm hex wrench, taking care not to strip the
head of the screw and making sure that the wire
is firmly gripped by the set screw.

7
AMPLIFIER MOUNTING OPTIONS CONTROL PANEL SECURITY COVER
The HD750/1 has two mounting options to The HD750/1 features a Control Panel Security
ease in installation. Cover. When installed, the cover ensures that
your amplifier settings are not accidentally
Standard Mounting changed while creating a clean aesthetic for the
amplifier and your installation. The control panel
security cover is pre-installed at the factory and
must be temporarily removed for access to the
controls described throughout this manual.

The security cover is secured by a single 2.5

mm hex-head screw at the far right of the panel.
Loosen the hex-head screw to release the security
cover (it is not necessary to completely remove the
The standard method of mounting requires screw). To re-install the security cover once all
removal of the four corner caps with the 3/16-inch adjustments have been made, insert the tongue on
hex wrench included with your amplifier. Using the cover's left edge into the groove where the left-
appropriate mounting screws (not included), side heatsink meets the control panel, hinge the
secure the amplifier in all four corners and panel closed and secure the screw using the
replace the corner caps. supplied 2.5 mm hex wrench. Do not overtighten
the screw.
Lateral Mounting Feet

Lateral Mounting Feet are also included with

your HD750/1 to provide an alternative mounting
option. Each mounting foot should be attached
to the bottom of the amplifier by screwing the
provided bolt into the bottom of the amplifier and
up into the corner cap with the supplied liS-inch
hex wrench. Next, using appropriate mounting
screws (not included), secure the amplifier by its
four Lateral Mounting Feet.

DIMPORTANTI
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.

8 I JL Audio - HD750/1 Owner's Manual

AMPLIFIER INPUTS iNPUT CONTROLS
The HD75011 has a single input section On the amplifier's control panel you will find
consisting of a pair of RCA-type input jacks on an "Input Voltage" range switch and a rotary
the Connection Panel of the amplifier and a control labeled "Input Sens." (Input Sensitivity).
pair of input controls on the Control Panel of These controls are designed to match the input
the amplifier: an "Input Voltage" switch and an sensitivity of the HD750/1 to the specific signal
"Input Sens." rotary control. source that is feeding it and must be adjusted,
with care, follOWing the procedures outlined in
this manual. Failure to make correct adjustments

Inputs
@(i can result in weak output, excessive distortion
and/or undesirable noise in the audio output of
the amplifier!

,@ (i
I- I ~
Low High 0118
lut Input Qu'
ns. Voltage Pol.
The HD750/1 features stereo inputs, even
though it is a mono amplifier. This has been
Monoblock Amplifier
done to permit the amplifier to sum stereo
input signals to mono, which is particularly
useful for driving subwoofers. Even if you
have a dedicated mono subwoofer signal "Input Voltage" Switch
available or are feeding a left channel only or A wide range of signal input voltages can be
a right channel only into the amplifier, you accommodated by the HD750/l's differential-
must feed both inputs of the HD750/1. balanced inputs (200mV - SV RMS). This wide
Connection of only one RCA input will result range is split up into two sub-ranges, accessible via
in reduced power output, increased distortion the "Input Voltage" switch. The "Low" position
and can cause the amplifier to overheat. To on the "Input Voltage" switch selects an input
connect a mono signal to both inputs, use sensitivity range between 200mV and 2Y. This
an RCA "Y-Adaptor" (sold separately). means that the "Input Sens." rotary control will
operate within that voltage window. If you are
using an aftermarket source unit, with preamp-
level outputs, this is most likely the position that
you will use (regardless of what voltage output
capability is claimed by the source unit).
The "High" position on the "Input Voltage"
switch selects an input sensitivity range between
SOOmV and Sy' This is for use with speaker-level
outputs from source units and small amplifiers
found in many OEM (factory-installed) systems.
To use speaker-level sources, splice the speaker
output wires of the source unit or small amplifier
onto a pair of RCA plugs for each input pair
or use the JL Audio ECS Speaker Wire to RCA
adaptor (XB-CLRAIC2-SW).

9
DIMPORTANTI CROSSOVER CONTROLS
The output of the amplifier decreases for a Crossovers are groups of electronic filters
given input voltage when the "Input Range" designed to control the frequency ranges
switch is placed in the "High" position. The that each speaker in a system will be tasked
output increases with the switch in the "Low" with reproducing. Proper crossover setup is
position. While this may sound counter- critical to sound quality and reliability.
intuitive, it is correct as described. The HD750/1 has one filter, which can be
configured as a high-pass filter (attenuates low
"Input Sens." Control frequencies) or as a low-pass filter (attenuates
Located to the left of the "Input Voltage" high frequencies). Additionally, the user can
switch is a rotary control labeled "Input Sens.". select from a shallow (l2dB/octave) filter slope
Once the appropriate "Input Voltage" range has or a more aggressive (24dB/octave) slope.
been selected, this control 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
Off I HP I LP
Filter
Mode
12dB I 24dB
Filter
Slope
,".:0
Filter Freq. (Hz)

for a given input voltage). To properly set the

.JL AUDIO. HC75
amplifier for maximum clean output, please refer
to Appendix C (pages 18, 19) in this manual.

1) "Filter Mode" Control: this switch allows you

to defeat or configure the filter into one of two
filter types:
Lov
Input II "Off": Defeats the filter completely, allowing
eq.(Hz) Sens. Vc
the full range of frequencies present at the
inputs to feed the amplifier. This is useful
HC750/1 Monoblocl
for systems utilizing outboard crossovers or
requiring full-range reproduction.

After using this procedure, you can then adjust "HP" (High-Pass): Configures the filter
the relative level by adjusting the input sensitivity to attenuate frequencies below the selected
downward, if it requires attenuation to achieve filter frequency. Useful for connection of
the desired system balance. component speakers in a bi-amplified system.
Do not increase the "Input Sens." setting for
any amplifier in the system beyond the maximum "LP" (Low-Pass): Attenuates frequencies
level established during the procedure outlined in above the selected filter frequency.
Appendix C (pages 18, 19). Doing so will result in Useful for connection of subwoofer(s)
audible distortion and possible speaker damage. in a bi-amplified system.

10 I JL Audio - HD750/1 Owner's Manual

 INFRASONIC FILTER
2) "Filter Slope" Control: This switch allows you The "Infrasonic Filter" is a 24 dB/octave high-
to select from two filter slopes: pass filter, with a fixed cutoff frequency of 30 Hz.
This filter is designed to conserve amplifier power
"12dB": Configures the filter to attenuate and protect subwoofer systems, without audibly
frequencies above or below the selected degrading the sub-bass output.
filter frequency at a rate of 12 dB per octave
(Butterworth alignment).

"24dB": Configures the filter to attenuate 080deg.

I-I
Off 30Hz
frequencies above or below the selected utput Infrasonic
,Iarity Filter
filter frequency at a rate of 24 dB per octave
(Linkwitz-Rileyalignment).

Depending on the speaker system and the

vehicle, different filter slopes may be required to
produce a smooth transition between the sound With ported enclosures, the use of the
of different speakers in the system. "Infrasonic Filter" is highly recommended to
In high-pass mode, the sharper "24dB" setting protect the speaker(s) from excessive excursion
will do a better job of protecting small speakers below box tuning.
with limited power handling. In low-pass With sealed enclosures, the use of the filter
mode, the "24dB" setting can also help by more is less necessary, but can still help protect the
aggressively removing lower midrange output speaker system from excessive excursion.
from a subwoofer system. The "Infrasonic Filter" can be completely
The shallower "12dB" octave setting defeated by selecting the "Off" position on its
allows for more output overlap between switch. This bypasses all signal from flowing
the speakers being crossed over. In many through the circuit.
cases, this will result in a smoother "blend"
or transition between speaker systems.
Experiment to find the slope or combination
of slopes which best matches the acoustic
requirements of your system.

3) "Filter Freq. (Hz)" Control:

This control selects the frequency at which the
filter begins to attenuate the signal and refers
specifically to the frequency at which output
has been attenuated by -3dB.

The filter frequency markings surrounding this

rotary 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 charts
in Appendix B (page 18) of this manual.

11
OUTPUT POLARITY CONTROL PREAMP OUTPUTS
Depending on the distance relationship of The HD750/1 incorporates a pass-through
the mid-bass speakers and the subwoofers in a preamp output section, so that additional
system, it can be desirable to reverse the polarity amplifiers can easily be connected to the same
of the subwoofer system in order to produce signal(s) feeding the HD750/1. These preamp
a better transition between subwoofer and output signals are accessible via a stereo pair
midbass speaker output. This is normally done of RCA-type jacks, labeled "Preouts", on the
by swapping the positive and negative wires Connection Panel.
connected to the subwoofer(s).

@,I Preouts R,
I High
Jut
tage
01180deg.
Output
Polarity
offl3C
Infraso
Filte @, i
Amplifier

The term "pass-through" refers to the fact that

The "Output Polarity" switch on the HD the Preamp Output signals are not affected by any
750/1 allows you to quickly peform this polarity crossover filter or input sensitivity setting selected
inversion without touching any wires. Simply on the HD750/1 (if the input signal is full-range,
flip the switch from the "0" (normal) to the "180 the Preamp Output will be full-range). These
deg." (reversed) position. preamp output signals are buffered to prevent
Neither switch position is "correct" for every noise and are always preamp level, regardless of
system. Experiment to determine which polarity the level of signals feeding the HD750/l's inputs.
produces the best overall bass performance
in your system, listening in particular to the
mid-bass smoothness and impact to make your
determination. If you change crossover slopes
or crossover filter frequencies, you may need to
revisit this control as these can affect the phase of
the speaker systems in the overlap region.

12 I JL Audio - HD750/1 Owner's Manual

REMOTE LEVEL CONTROL (OPTIONAL) SPEAKER CONNECTIONS
With the addition of the optional Remote Level The HD750/1 employs JL Audio's exclusive
Control (HD-RLC), you can control the volume Regulated, Intelligent Power Supply (R.LP.S.)
of the HD750/1 from the front of the vehicle. This design. This sophisticated power supply allows
is particularly useful for subwoofer level control. the amplifier to produce its optimum power (750
The HD-RLC connects to the jack labeled watts x 1) over a wide range of supply voltage and
"Remote Level Control" on the Connection speaker impedances.
Panel of the amplifier using a standard telephone
cable (supplied with the HD- RLC).
If desired, multiple HD amplifiers can be ®
controlled from a single HD-RLC controller e 0 e 0
using a simple phone line "splitter" and multiple @

m:u
( SPEAOCER OUT J
phone cables (not supplied).

Unlike conventional amplifiers that require

Preouts a specific impedance to produce optimum
Remote
Level
Control power, the R.LP.S.-equipped HD750/1 gives
you the freedom to use a variety of speaker
configurations that achieve final nominal
impedances between 1.5 - 4Q (without
sacrificing power output or sound quality).
When connected to the amplifier, the HD-RLC The operation of the R.LP.S. circuitry is
operates as follows. At full counter-clockwise entirely automatic and adjusts itself every time the
rotation, the audio will mute completely. At full amplifier is turned on. There are no user controls
clockwise rotation the level will be the same as if to configure. The system operates through
the HD-RLC was not connected at all. In other multiple stages of impedance optimization,
words, it operates strictly as a level attenuator. choosing the stage most appropriate to the actual
impedance of the speakers you connect to it.

DIMPORTANTI
The RBC-I Remote Bass Control used with DIMPORTANTI
JL Audio Slash, Slash v2, e-Series, A-Series and If you connect a load higher than 40 nominal,
G-Series amplifiers is NOT compatible with the power will drop by half with every doubling of
HD Series amplifiers. If you attempt to connect impedance above 40 stereo. If you connect a
an RBC-l to an HD amplifer, the control will load lower than 1.50 nominal, the amplifier
not work. You must use the HD-RLC controller. protection circuitry activates a "safe" mode
which reduces amplifier power to protect the
circuitry from failure (the LED status indicator
on the control panel will light up amber to
indicate that this has happened). See page 14
for details.

13
DIMPORTANTI "STATUS" LED / PROTECTION CIRCUITRY
Speaker loads below 1.50 nominal are not There is a single multi-color LED on the
recommended and may cause the amplifier control panel of the amplifier to indicate the
output to distort excessively. amplifier's operating status. This LED's behavior
is as follows:
Speaker Connector Plugs
To connect the speaker wires to the amplifier, 1) Flashing Green: amplifier is powering up,
unplug the speaker connector plug from the audio output is muted.
amplifier chassis (pull back firmly) and back out
the set screws on the connector plug, using the 2) Constant Green: amplifier is on and
supplied 2.0 mm hex wrench. Strip 3/8 inch (10 functioning normally, audio output is active.
mm) of insulation from the end of each wire and
insert the bare wire into the receptacle on the 3) Constant Red: lights to indicate that the
speaker connector plug, seating it firmly so that amplifier has exceeded its safe operating
no bare wire is exposed. While holding each wire temperature, putting the amplifier into a
in place, tighten each set screw firmly, taking care self-protection mode, which reduces the
not to strip the head of the screw. peak power output of the ampli fier. The red
light will turn green and the amplifier will
return to full-power operating mode when its
temperature returns to a safe level.

3) Constant Amber (yellow): lights to indicate

that the impedance of the speaker load
connected to the amplifier is lower than its
optimum load impedance range. When this
light is on, a protection circuit engages and
reduces the power output of the amplifier.
The amber indicator will also light when a
You will notice that there are two sets of"+" and short-circuit is detected in the speaker wiring
"-" connections on the plug. This is to facilitate (this can be a short between the positive and
multiple speaker wiring to the HD750/l's mono negative speaker wires or between either
output. The two positive and two negative speaker wire and the vehicle chassis).
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.

DIMPORTANTI
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
and mute the output.

14 I JL Audio - HD750/1 Owner's Manual

 SERVICING YOUR JL AUDIO AMPLIFIER
4) Alternating Red and Green: lights to indicate If your amplifier fails or malfunctions, please
that the amplifier is experiencing a fault return it to your authorized JL Audio dealer so
that may require service of the amplifier, its that it may be sent in to JL Audio for service.
wiring or the vehicle's charging system. Audio There are no user serviceable parts or fuses inside
is muted when this fault occurs. The most the amplifier. The unique nature of the circuitry
likely cause of this fault is a low supply voltage in the JL Audio amplifiers requires specifically
condition. If battery voltage drops below 8.5 trained service personnel. Do not attempt
volts at any point, the amplifier (except for the to service the amplifier yourself or through
"Status" LED) will shut itself off to protect itself unauthorized repair facilities. This will not only
and the vehicle's charging system. If the voltage void the warranty, but may result in the creation
drops below 6 volts, the "Status" LED will also of more problems within the amplifier.
turn off.

The amplifier will turn back on automatically

when voltage climbs back above 9 volts. This
shut-down and turn-on behavior may happen If you have any questions about the installation or
in a rapid cycle when bass-heavy program setup of the amplifier not covered in this manual,
material causes a weak charging system to please contact your dealer or technical support.
momentarily dip too low. If this is happening
in your system, have your charging system JL Audio Technical Support:
inspected to make sure it is working properly. (954) 443-1100
9:00 AM - 5:30 PM (Eastern Time Zone)
If no problem is found with the supply Monday - Friday
voltage to the amplifier and you are
still seeing alternating Red and Green'
on the "Status" LED, it is likely that the
amplifier is suffering from an internal
fault that requires factory service.

For more information on troubleshooting this

amplifier, refer to Appendix D (pages 20, 21).

15
16 I JL Audio - HD750/1 Owner's Manual
 APPENDIX A:
HD7S011 Specifications
Amplifier Topology: Class D, switching type with
patented Single-Cycle Control'M technology.
Power Supply: Pulse width modulation-regulated
switching power supply
Recommended Fuse Value / Type: 60A (AFS, AGU or
MaxiFuse™)
Rated Power:
750W RMS xl @ 1.5-40 (11V - 14.5V)
THD at Rated Power: <0.03% @ 40
(Average at 1 kHz)
Signal to Noise Ratio (20 kHz Bandwidth):
Referred to Rated Power 111 dBA
Referred to 1 Watt: 82.2 dBA
Frequency Response: 6 Hz - 30 kHz (+0, -1 dB)
Damping Factor:
>500 @ 40 per ch.1 50 Hz
>250 @ 20 per ch.1 50 Hz

Crossover Filter:
Filter Type: State-variable, 12 dBloctave Butterworth or
24 dB/octave Linkwitz-Riley
Filter Modes: Low-Pass or High-Pass, Defeatable.
Cutoff Freq. Range: Continuously variable, 50 - 500 Hz

Input Sections:
No. of Inputs: One Stereo Pair, sums to mono
InputType: Differential-balanced with RCA jack inputs
Input Range: Switchable from 200mV - 2V RMS (Low)
to 800mV - 8V RMS (High)

Preamp Output:
2-Channel, buffered pass-through type

Chassis Dimensions (LxWxH):

10.74 in. x 7.85 in. x 1.93 in. (273 mm x 199.5 mm x 49 mm)
Dimensions do not include connectors

Due to ongOing product developl1l~nt. :111 specifications are subject to

change without notice
. _.. - - - - - - - - _ ... _ . _ . _ - - - - - ~ - - - - __------
.. - - - - _.. _. __ . __._._-_ •.... - .. __.. -----

17
APPENDIXB: APPENDIXC:
Precise Frequency Selection Chart Input Sensitivity Level Setting
JL Audio amplifiers utilizing the Regulated
"FILTER FREQ"
Intelligent Power Supply (R.I.P.S.) allow
Detent Panel Actual
Number Marking Freq. delivery of their rated power when connected
Full counter-clockwise: 58 to any load impedance from 1.5 - 40 per
01... . 53 channel and when connected to a charging
02... .. "50". . . .53 system with any voltage from 11 - 14.5V.
03 53 This design is beneficial for many reasons.
04......... . .53 One of these reasons is ease of setup.
05 .54 Because each JL Audio amplifier will
06 56
always deliver the same amount of power
07 58
within its operational range of impedances
08 "60". ..60
and supply voltages, the maximum,
09 62
10 64 unclipped output is very predictable.
11 66 This makes setting the gain structure via the
12 68 input sensitivity controls very simple. Following
13.......... .. 71 the directions below will allow the user to adjust
14......... . 74 the input sensitivity of the amplifier(s) simply
15.. . 76 and easily in just a few minutes using equipment
16 . "80"... . 80 which is commonly available in installation bays.
17.......... . 83
18........... .. ..87
Necessary Equipment
19.......... . 91
20.. . 94 • Digital AC Voltmeter
21 . 99 • CD with a sine-wave test tone recorded at
22 104 odB reference level in the frequency range
23 109 to be amplified for that set of channels
24 "120" 115 (50 Hz for subwoofer channels, 1 kHz for
25. .. 121 a midrange application). The CleanSweep·
26... .. 128 Calibration Disc contains the appropriate
27 .. . 137 test tones and is available for sale at
28... . 147
http://store.jlaudio.com Do not use attenuated
29 160
test tones (-10 dB, -20 dB, etc.).
30.......... .. 174
31 .. 191
32 "200" 211
33......... .. 236
34.......... .. 269 Do not increase any "Input Sens." setting in
35.. .. 309 the system beyond the maximum level
36. . 369 established during this procedure. Doing so
37................ .. .443 will result in audible distortion and possible
38 "500" 484 speaker damage.
39 525
Full-clockwise: 528
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, source unit tone controls or EQ
circuits. EQ cuts will not require re-adjustment.

18 I JL Audio - HD750/1 Owner's Manual

The Nine-Step Procedure
1) Disconnect the Speaker Connector Plug. 6) Verify that you have disconnected the Speaker
2) Turn off all processing on the source unit Connector Plug before proceeding. Playa
(bass/treble, loudness, EQ, etc.). Set fader track with an appropriate sine wave (within
control to center position and subwoofer the frequency range to be amplified by each
level control to 3/4 of maximum (if set of channels) at 3/4 source unit volume.
used to drive the HD750/l). Disconnect 7) Connect the AC voltmeter to the Speaker
the HD-RLC Remote Level Control Output contacts of the amplifier.
temporarily (if one is being used). 8) Increase the "Input Sens." control until the
3) Switch the "Input Voltage" to "Low" and turn target voltage is delivered. If excessive voltage
the "Input Sens." control all the way down. is read with the control at minimum (full
4) Set the source unit volume to 3/4 of full counterclockwise), switch the "Input Voltage"
volume. If the amplifier is being driven by a switch to "High" and re-adjust.
source unit's dedicated subwoofer output, also 9) Once you have adjusted the amplifier to its
adjust the source unit's subwoofer level control maximum unclipped output level, reconnect
to 3/4 of maximum output. This will allow for the speaker(s). The "Input Sens." controls can
reasonable gain overlap with moderate clipping now be adjusted downward if the HD750/1
at full volume. requires attenuation to achieve the desired
S) Using the chart below, determine the system balance.
target voltage for input sensitivity
adjustment according to the nominal
impedance of the speaker system
connected to each set of outputs.

HD 750/1
Nom.
Impedance
(MONO)

80 54.8 V
"

60 54.8V
"'i
40 -CO" 54.8 V

30 47AV

20 38.7 V

1.50 33.5 V

19
APPENDIX D: TROUBLESHOOTING
"How do I properly set the input sensitivity on my amplifier"
Please refer to Appendix C (pages 18, 19) to set the input sensitivity
for maximum, low-distortion output.
"My amplifier doesn't turn on"
Check the fuse(s), 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.

"I get a distorted I 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 a speaker lead and
the vehicle's chassis ground. If a short is present, you will
experience distorted and/or attenuated output. The "Status"
LED will turn amber (yellow) 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 the amplifier is
driving a load equal to or greater than 1.5 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 connector plugs.
Check the input connectors to ensure that they all are making good
contact with the input jacks on the amplifier.

--_._---------------- ----
20 I JL Audio - HD750/1 Owner's Manual
liMy amplifier shuts off once in a while, usually at higher volumes"
Check your voltage source and grounding point. The power supply
of the HD7S0/1 will operate with charging system voltages
down to 8.SV. Shutdown problems at higher volume levels
can occur when the charging system voltage drops below
8.SV. 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."

liMy 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 th~ amplifier
(example: 50 Hz for a sub bass application or 1 kHz for a full
range / high-pass application). A steady, sufficient voltage
(between 200mV 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 Connector Plugs
from the amplifier while doing this. Turn the volume up
approximately half way. SV 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.
Check to ensure that the speaker wires are making a good
connection with the metal inside the Speaker Connector
Plugs. The speaker wire connectors are designed to accept up
to 12 AWG wire. Make sure to strip the wire to allow for a
sufficient connection with the metal inside each terminal.

21
INSTALLATION NOTES:
Use this diagram to document your amplifier's switch and control positions.

~
(

© I
Off I HP I LP
I I
12dB I 24dB
I wQ:200
so 500
~
0Status
Filter
Mode
Filter
Slope Filter Freq. (Hz)
Ii
S

..JL AUDIO. HC750/1

22 I JL Audio - HD750/1 Owner's Manual

 ~
\

~ I I I I I I @
Low I High 01180 deg. Off 130Hz

.,
It Input
Voltage
Output
Polarity
Infrasonic
Filter 0

lI1onoblock Amplifier
I
J
~

23
 LIMITED WARRANTY - AMPLIFIERS (USA)

JL AUDIO warrants this product to be free of defects in materials and workmanship for a period of
two (2) years from the original date of purchase.
This warranty is not transferable and applies only to the original purchaser from an authorized
JL AUDIO dealer. Should service be necessary under this warranty for any reason due to manufacturing
defect or malfunction, JL AUDIO will (at its discretion), repair or replace the defective product with new
or remanufactured product at no charge. Damage caused by the following is not covered under warranty:
accident, misuse, abuse, product modification or neglect, failure to follow installation instructions,
unauthorized repair attempts, misrepresentations by the seller. This warranty does not cover incidental
or consequential damages and does not cover the cost of removing or reinstalling the unit(s). Cosmetic
damage due to accident or normal wear and tear is not covered under warranty.

Warranty is void if the product's serial number has been removed or defaced.

Any applicable implied warranties are limited in duration to the period of the express warranty as
provided herein beginning with the date of the original purchase at retail, and no warranties, whether
express or implied, shall apply to this product thereafter. Some states do not allow limitations on implied
warranties, therefore these exclusions may not apply to you. This warranty gives you specific legal rights,
and you may also have other rights which vary from state to state.

If you need service on your JL AUDIO product:

All warranty returns should be sent to JL AUDIO's Amplifier Service Facility freight-prepaid through
an authorized JL AUDIO dealer and must be accompanied by proof of purchase (a copy of the original
sales receipt). Direct return§. from consumers or non-authorized dealers will be refused unless specifically
authorized by JL AUDIO with a valid return authorization number.
Warranty expiration on products returned without proof of purchase will be determined from the
manufacturing date code. Coverage may be invalidated as this date is previous to purchase date. Non-
defective items received will be returned freight-collect. Customer is responsible for shipping charges and
insurance in sending the product to JL AUDIO. Freight damage on returns is not covered under warranty.

For Service Information in the U.S.A. please call

JL Audio Customer Service: (954) 443-1100
9:00 AM - 5:30 PM (Eastern Time Zone)
JL Audio, Inc
10369 North Commerce Pkwy.
Miramar, FL 33025
(do not send product for repair to this address)

International Warranties:
Products purchased outside the United States of America are covered only
by that country's distributor and not by JL Audio, Inc.

Single-Cycle Control'" (U.s Patent #6,084,450) is used under exclusive license for mobile audio from Power Physics, Inc - Newport Beach, CA

Printed in China HD750/1 MAN-CH-0408