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Plan it out
first.
- Decide where you are going to mount the
amp(s).
- Decide how much, and
what gauge power cable you will need.
- Decide how long your RCA cables will need
to be. You should take into account that the cable will be running from
the center of the car, out to the side, and around several bends and
curves.
- When deciding how much power cable, think
about how you will run the cables first! You don’t want to get 18 feet of
cable, and then realize you can’t go down the middle of the car, you have
to go down the side, and it needed to be 2 feet longer!
- It is often easier to just take out the
seats, kick panels, and sill plates before starting. It just makes it
easier to work, and often you need to do all that anyway. Removing the
front seats is optional, but it gives you more room, easier to lift the
carpet, and it is often best to run the wires there. As you remove the
seats, take note of where they run close to the floorpan. It's easy to
accidentally crush your wiring when bolting the seat down, and that is
very frustrating. Once you set your mind to it, it’s really not that hard.
A cordless drill and a socket set make it a breeze. I have taken apart
many an interior in 10 minutes, and can assemble it again in about 15, if
I am in a hurry.
Mount the amp(s).
- Find a good solid, flat surface to mount
the amp to. Make sure it’s not in a place that will be hot, or not have
proper ventilation. Amps can get hot anyway, and you must help them stay
cool, for longer life, and less chance of thermal shutdown. If you want,
you can mount a board with vinyl, or carpet on it, for cosmetics, and
mount the amp to it. You can also mount your power distribution blocks to
this board. Mounting to an amp board also reduces the amps contact with
metal, and that helps to prevent "ground loops".
RCA's
- Get a good quality set of RCA cables.
Normally, a simple pair of shielded RCA's work fine.
- Connect a remote turn on lead wire to
your "power antenna" or "remote" lead from the head unit. Run the RCA
cables, and remote lead, from the head unit, down the middle of the car,
or down the opposite side of the car from the power cable. The remote lead
will serve as a turn-on for your amp(s). This doesn’t have to be very
thick wire, 16 gauge is fine. If you have room, you can usually remove the
sill plate, and lift the edge of the carpet, and run the cable(s) there,
proceeding to the back of the car. Be sure not to put them anywhere they
will get crushed by anything. Run all the wires to where the amp will be
installed.
Positive Power cable
- Find a spot to go through the firewall.
Look for a plug that’s already there. If you find one, you can often make
a grommet out of it. If there is none, don’t worry. Just find a place to
drill, on the same side as the battery, and install a grommet. Run the
cable through the firewall, and up to the battery. Don’t connect it to the
battery till you are all done. Most cars will have grommets large enough
to use. Don't worry if there already are factory wires in your grommet,
just be careful not to damage them as you run the wire through. One
helpful method is to get a long thick probe (an old car antenna mast works
great for this). Grind the tip to a point, but don't sharpen it. You can
tape your power wire to this probe, and run it through the grommet. If
your wire is fairly large compared to the grommet, than you may wish to
tape a smaller gauge wire to act as a leader.
- Within 6"-18" of the battery, install an
inline fuse. For most systems, a 50 or 60 amp fuse is plenty. If it’s only
a small amp 30 or 40 will do. DO NOT skip this fuse! This one is
mandatory! It could stop your car from catching on fire in an accident.
See MORE on FUSING.
- With the wire through the firewall, run
the cable to the back of the car, staying on the opposite side of the RCA
cables. If you are going to have more than one amp, you want to install a
distribution fuse block. Connect the power cable to this fuse block. You
then run another cable from the fuse block, to the amps positive (+)
terminal.
- Be sure to use split loom tubing to
protect your power wire under the hood. This is an IASCA requirement.
Also, use loom anywhere a wire runs over a rough metal edge. Use wire ties
to keep the wire from being drooped over your engine.
Ground Cable
- This is where most people make mistakes.
This is important! First, install a ground cable from the negative post on
the battery, to the chassis of the car. If you can reach it, it's best to
run it to the firewall, since most cars are a nearly solid sheet of metal
from the firewall to the trunk. Make it the same size, or larger than the
positive cable. I like to run a 4 gauge or larger to the engine block, AND
a 8 gauge or larger to the chassis. Don’t be afraid of over kill here. You
spent good money on your amps and the rest of your system. Don’t skimp on
a 2 foot length of cable now. I use 0 gauge cable on my own car to the
engine block, and 2 gauge to the chassis. Near the firewall, I also
sometimes add a piece of 4 gauge from the block, to the firewall.
- Near the amp, install a ground
distribution block.
- Find a spot as close as possible to this,
to connect a ground cable. You can connect it to an existing bolt, or use
a self-tapping screw, or drill, and use a bolt, and nut. If your gonna
drill, make sure you don’t drill into your gas tank! The main thing is,
wherever you do it, make sure you sand off all the paint, and put it right
on the bare metal. You can use some Vaseline here to prevent corrosion,
and rust.
- Now connect the cable from the chassis,
to the distribution block.
- Run a piece of cable from the
distribution block, to the amps negative (-) terminal.
Finishing up
- Connect the RCA cables to the amp(s). Do
not connect them before you have grounded your amplifier, and wait till
you connect the battery terminal. Often, the biggest mistake people make
is to have their RCA's hooked up the first time their amps get a charge.
Since the outer shield of the RCA's are grounded, the amp will try to take
some of it's ground through them, damaging the preamp of your radio and
amplifier.
- Connect your remote lead to the amps
remote connection.
- Connect your speaker wires to the amp.
(That’s in a different lesson, but the wires should be run at the same
time the amp wiring is done.)
- Go back and connect the positive cable to
the positive terminal on the battery.
- Now, if your amp(s) have gain controls
(and most do nowadays) turn them all the way down to the minimum setting.
Now turn it just a hair the other way.
- If you have built-in crossovers, set them
the way you will be using them (hi-pass, low-pass, none, etc.….). If they
are adjustable, put them approximately where you think will be a good
starting point.
Turn the key on
- Turn on your head unit. Put in a good
quality CD, or cassette.
- Slowly turn your head unit up to about
80-85% volume. If you hear any distortion, cut it back.
- Go back to the amp(s). SLOWLY raise the
gain, and LISTEN for distortion. If you reach a point where the volume is
louder then you will listen to, before you hear distortion, then stop
there. Otherwise, keep going till you hear distortion, and cut it back
slightly till it disappears. Remember that volume setting! That is the
max. volume you want to play it at.
- It’s not a good idea to play the head
unit at full volume. That’s where most distortion comes in. It may take
you a long time to fine tune your amp(s) gains, and crossovers.
- Grab some good CDs (or tapes, if you
don’t have CD) and go for a ride. Listen to all types of music, and stop
the car, and make adjustments as necessary.
- If you have multiple amps, and an
equalizer, it will take much longer to get it set the way you want it. But
this is the fun part! For MORE info on setting up
multistage gains, go HERE.
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