How to install a car amplifier

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How to install a car amplifier
Install a Car Amplifier

To get the full effect of your car's audio system, you may want to install a car amplifier to power the speakers. Additionally, if you wish to use subwoofers you'll need an amplifier to power them. Installing a car audio amplifier yourself is a fairly simple task that will save you money on your car stereo system. This guide shows you how to install a car amplifier for either of the above purposes.

Skill level:

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Things you need

  • Wire Cutters and Pliers
  • Car Manual
  • O-ring Ends
  • Car Audio Cables and Wires
  • Sandpaper
  • Utility Knife
  • Masking Tape and Pen
  • Wire Strippers
  • Female Spade Connectors
  • Screwdrivers
  • Car Audio Amplifier

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  1. 1

    Choose where to put your new amp. If you are installing subwoofers it's usually best to put the amplifier in the trunk next to or attached to your subwoofer enclosure. If you are going to power your main car speakers with the amplifier then it may be better to put the amp under the passenger's seat.

  2. 2

    Purchase the following wiring for the amp: A thick power cable (the thickness required depends on the total wattage of your amp, ask a sales rep or consult your amplifier's manual for the proper gauge) that will have to reach from your battery to the amp (the power cable should also have an inline fuse to protect the amplifier); 3 feet of ground cable of equal thickness as the power cable; an RCA signal cable to carry the left and right signals from your head unit to the amp; a "remote on" wire which can be any thin wire (20 to 24 gauge) that will also run from the head unit to the amp; speaker wire (if you are powering subwoofers you should only need about 3 feet of 12-gauge wire per sub, if you're going to power your main speakers you will need enough 16-gauge wire to reach each speaker from the amp, 12 feet per speaker is usually safe).

  3. 3

    Gather the following tools: Screwdrivers, wire cutters, wire strippers, pliers, a utility knife, sandpaper, masking tape with a pen for labeling, 2 crimp-on o-ring ends for the power and ground cables. If you're hooking the amp to your speakers, you'll also need 2 crimp-on female spade connectors for each speaker.

  4. 4

    Find a manual with instructions on taking off the dash of your car (not the whole dash--just the head unit, in order to hook wires to the back), and also to get at your car's speakers if you are hooking the amp to them.

  1. 1

    Disconnect the ground (negative) cable from your battery. Never work on the electrical system of your car with this connected.

  2. 2

    Attach the side with the fuse of the thick positive (+/red) power cable to the connector on the positive terminal of your battery; the o-ring can be sandwiched in the bolt on the connector that connects your car to the battery. Now put the fuse in the fuse holder.

  3. 3

    Run the power cable through the firewall of your car (there is usually an opening on the driver's side) and to your amplifier. If your amp is in the back it is usually best to run this wire under the plastic molding that goes along the bottom edge of your car. Be careful where you run the wire because the power cables should never be near the signal or speaker wires.

  4. 4

    Find a metal bolt or screw on the metal of your car near the amp to connect the ground cable to. This should be as close to the amp as possible, never more than 3 feet. Unscrew it and clean the metal surface with sandpaper. Attach the ground to it with the o-ring and screw it back down firmly.

  5. 5

    Remove your head unit and run the signal and remote on wires from behind the head unit to your amp. Connect the RCA connectors and the remote on wire to the back of your head unit.

  6. 6

    (If you are installing subwoofers and not running your normal speakers off the amplifier skip to step 7.) Run the 16-gauge wire from each one of your speakers to the amplifier. On the amp side use the masking tape to label each wire so you know which speaker it is. On the speaker end-strip a 1/4 inch off the ends of the wires and crimp on the female spade connectors with your pliers. Connect the spade connectors to your speakers making sure to match the positive (+/red or white) with the positive terminal and the negative (-/black) with the negative one.

  7. 7

    Connect everything to your amplifier. Only strip off as much as you need off the end of each wire to make a solid connection, you don't want any exposed wire hanging out. If you have subs, attach them to the amp with the 12-gauge speaker wire.

  8. 8

    Secure your amp to something. If it is in the back you can screw it directly to your subwoofer enclosure. If it is under a seat you may just want to get some straps that hold it down.

  9. 9

    Reconnect your car's negative cable to the battery. Test your system and make sure everything works, going around to see that every speaker is on before you put everything back together.

  10. 10

    Put everything back together.

Tips and warnings

  • The head unit is your cassette or CD player that sits in the dash of your car.
  • If your head unit is old or is stock, you may not have RCA outputs in the back. In this case you will need an amplifier that has "speaker level" inputs and you will attach the lines that come out of your head unit and would normally go to the speakers to the amp instead.
  • Read the manual for your amplifier, it will give you all sorts of helpful information like the proper gauges of wire and what fuse to use.
  • The most common cause of an amplifier not turning on is a bad ground. If the amp isn't working try a different spot to connect the ground cable to.
  • Stock speakers are not meant to handle the power put out by a car audio amplifier. If you hook the amp to your stock speakers you will probably blow them.
  • Never ever work on the electrical system of your car with the ground wire attached to the battery. You can damage yourself and your equipment.
  • Never have your speaker or signal wires run near your amplifier's power cables. If they must cross do so perpendicularly and only in one spot.

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