The remote turn on wire goes to the head
unit. When the radio is on, it puts out 12 volts
that turn the amplifier on. If you are using a
factory radio that does not have a remote turn on (or
power antenna wire) you can tap into, hook it up to the
ignition, so that the amplifier does not remain on when
you turn the car off.
If you are using multiple devices (amplifiers,
crossovers, equalizers, fans, etc), you might have to
add a relay, since typical turn-on wires in a radio can't
handle more that 300mA.
Power Wiring
Even though amplifiers are easy to install,
a lot of things could go wrong. The most important thing
to consider is where to get the power from: Straight
from the battery. ALWAYS put a
fuse as close to the positive battery terminal as possible.
If the wire going to the back of the car shorts out,
then the fuse will blow. If you don't install a fuse
or breaker and the wire shorts out, then the wire will
carry so much current that the insulation will melt and
could catch your car on fire. The size of the fuse should
be the same rating as the fuses used by the amp(s) or
less. The ground (-) should be hooked-up to a metal part
of the car. It is not necessary to run a ground wire
all the way to the battery.
It is not essential to spend a lot of
money in getting 99.999999% copper 0-gage wire and gold
connectors unless you are installing a competition system.
Here's a table to help decide what gauge wire to use,
based on total current draw and length of wire:
Power Cable Calculator
Total Amperage
Draw of System
Up to 4 ft.
4 to 7 ft.
7 to 10 ft.
10 to 13 ft.
13 to 16 ft.
16 to 22 ft.
22 to 28 ft.
0 - 20
14
12
12
10
10
8
8
20 - 35
12
10
8
8
6
6
4
35 - 50
10
8
8
6
4
4
4
50 - 65
8
8
6
4
4
4
2
65 - 85
6
6
4
4
2
2
0
85 - 105
6
6
4
2
2
2
0
105 - 125
4
4
4
2
0
0
0
125 - 150
2
2
2
0
0
0
00
The above
chart shows wire gauges to be used if no less than
a .5 volt drop is accepted.
Cable size calculation takes into account terminal
connection resistance.
RCA Wiring
When running power wires to the amp,
keep them as far away from the RCA wires (see alternator
noise section for more info), ideally on the other side
of the car. It is OK to run the turn-on wire from the
radio along with RCA's, since it carries very little
current.
Mounting
Amplifiers produce a lot of heat and
need to receive plenty of fresh air. If the amplifier
is to be mounted under a seat, upside down, in a rack
or enclosed, a fan or two might need to be used to increase
air flow.
To avoid noise problems, it is good practice
to mount the amplifier itself to a piece of wood or other
non-conducting material. That way the only ground
it gets is from the ground wire and not the mounting
screws.
