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| JL Audio - HD900/5 Owner’s Manual
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ground Connection
The chassis ground connection must be made
using 4 AWG pure copper wire and should be
kept as short as possible, while accessing a solid
piece of sheet metal in the vehicle. The surface of
the sheet metal should be sanded at the contact
point to create a clean, metal-to-metal connection
between the chassis and the termination of
the ground wire with a brass or copper power
ring. 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.
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 pure copper wire when installing amplifier
systems with main fuse ratings above 60A.
turn-on wire
The HD900/5 uses a conven12V remote
turn-on wire, 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 HD900/5’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 hex wrench. Strip 1/2 inch (12mm) 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 be necessary to
strip 1 inch of insulation from the wire and fold
the bare wire in half prior to insertion. While
holding the wire in the terminal, tighten the
set screw firmly using the supplied 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.
amplifier Power Connector Plug
To connect the power wires and the remote
turn-on wire to the amplifier, unplug the power
connector plug from the amplifier chassis (pull
back firmly) and back out the set screws on
the connector plug, using the supplied 4 mm
hex wrench for the +12 VDC” and “Ground”
connections and the supplied 2.5 mm hex wrench
for the “Remote” connection. Strip 3/8 inch (10
mm) of insulation from the end of each wire and
insert the bare wire into the receptacle on power
connector plug, seating it firmly so that no bare
wire is exposed. While holding each wire in place,
tighten each set screw firmly, taking care not to
strip the head of the screw.
Never make power connections with a “live”
wire. Always disconnect the negative battery
post before making any connections or
adjustments to a 12V power connection!
Power and turn-on 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.
+12V battery Connection
You will need to connect a power wire to
the vehicle’s positive battery terminal, using
an appropriate power ring or specialized
battery terminal connector, such as the JL
Audio XB-BTU or XD-BTS. This connection
must be tight and corrosion-free to ensure
proper connectivity. This wire MUST be fused
appropriately for safety. Any power wires run
through metal barriers (such as firewalls), must
be protected with a high quality insulating
grommet to prevent damage to the insulation
of the wire. Failure to do so may result in a
dangerous short circuit.
Power wire requirements
The HD900/5’s “+12 VDC” and “Ground”
connections are designed to accept 4 AWG
power wire. 4 AWG pure copper wire is
the minimum recommended wire size for
this amplifier. Use of smaller gauge wire
(including cheap wire that is fraudulently sold
as 4 AWG wire) can create a fire hazard.
If you are installing the HD900/5 with other
amplifiers and wish to use a single main power
wire, use 2 AWG or 1/0 AWG pure copper
wire as a main power wire. This 2 AWG or
1/0 AWG power wire should terminate into a
fused distribution block mounted as close to the
amplifiers as possible and should connect to the
HD900/5 with 4 AWG pure copper power wire,
with each smaller wire fused appropriately for
each amplifier or other electronics in the system.
Please note that lower 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.).
We do not recommend the use of “copper-
clad aluminum wire” or “CCA” wire because
this wire is significantly less conductive than
pure copper wire. Only use pure copper power
wire, such as JL Audio’s Premium Power Wire
Premium Power Wire. Tinned copper wire
(silver color) is acceptable as the tin-plating is
only a very minor component of the wire.
Fuse requirements
The installation of a fuse on the main 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 short-circuit. The fuse value at each power
wire should be just high enough for all of the
equipment being run from that power wire. Do
not use a fuse with a value that far exceeds the
total fuse rating of the electronics connected to
the wire.
If only the HD900/5 is being run from
a single power wire, install a 60A fuse to
protect the wire: AGU (big glass fuse). AFS
(small blade fuse) or MaxiFuse™ (big plastic-
body fuse) types are recommended.
If other amplifiers are also being powered from
a main power wire and exceed 80 amps in total
fuse rating, we recommend the use of an ANL
(large-blade) fuse and holder at the battery plus a
fused distribution block near the amplifiers. Each
amplifier must be fused independently at the
outputs of the fused power distribution block. We
recommend appropriately rated MaxiFuse™ fuses
and a JL Audio fused distribution block.
Please consult with your JL Audio
dealer to make sure that the wire, fuse
holder and fuse ratings are appropriate
for your system’s needs. The safety of
your installation depends on appropriate
power connections and fuse protection.
