4 | JL Audio - HD1200/1 Owner’s Manual
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 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. 2 AWG or larger is recommended
for wire runs greater than 72 inches (180
cm) in length. This 2 AWG wire needs
to be reduced to 4 AWG within 36 wire
inches of the amplifier using a distribution
block. Use a 1/0 AWG or 1/0 AWG main
power wire with a fused power distribution
block when additional amplifiers are being
installed with the HD1200/1 and are being
powered from the same main power wire.
3) Connect power wire to the positive battery
post. Fuse the wire with an appropriate fuse
block (and connectors) within 18 inches (45
cm) wire length of the positive battery post.
This fuse is essential to protect the vehicle.
Do not install the fuse until the power wire
has been connected to the amplifier.
4) Run signal cables (RCA cables) and remote
turn-on wire from the source unit 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, bare metal grounding
point close to the amplifier and connect the
negative power wire to it using appropriate
hardware. Use minimum 4 AWG power wire,
no longer than 36 inches (90 cm). In some
vehicles, it may be necessary to upgrade the
battery’s ground wire as well. (See pages 6, 7
for important notice).
7) Securely mount the amplifier using
appropriate hardware. (See page 8 for detailed
8) Connect the remote turn-on wire and the
positive and negative power wires to the
amplifier’s power connector plug. Then insert
the power connector plug into the amplifier’s
power connector receptacle, pushing firmly.
9) Connect the RCA input cables
to the amplifier.
10) Connect the speaker wires to the speaker
connector plug and insert the plug firmly into
the speaker connector receptacle.
11) Carefully review the amplifier’s control
settings to make sure that they are set
according to the needs of the system.
12) Install power wire fuse (100A for a
single HD1200/1) and reconnect the negative
battery post terminal.
13) 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
14) Make necessary adjustments to the input
sensitivity controls to obtain the right
overall output and the desired balance
in the system. See Appendix C (pages 18, 19)
for the recommended input sensitivity
15) Enjoy the fruits of your labor with your
The JL Audio HD1200/1 is a very powerful
and compact monoblock (single channel),
wide-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
HD1200/1 is a wide-range design, so it can
be used as a subwoofer amplifier or as a very
powerful mid-bass or mid-range amplifier,
using a second 1200/1 to form a stereo pair.
Its effective frequency response is from 6 Hz
(very low bass) to 8 kHz (lower treble range).
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 HD1200/1’s performance
capabilities with a wide range of speaker systems.
The tightly regulated power supply design also
means that the HD1200/1’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 HD1200/1’s
preamp output can send pass-through signals
from the inputs to feed additional amplifier(s).