How to Run a Car Amp on AC Powerby William Kinsey
Cars operate on a 12-volt electrical system, which provides a lot of current at low voltage. Car amplifiers are designed to use the direct current (DC) from the car’s battery and alternator for power. This is different from a home electrical system, which uses alternating current (AC) and provides 110 to 120 volts at a lower current. To run a car amp from an AC circuit, you must first convert from AC to DC power.
Unplug the power supply and make sure it is switched off. The power supply will provide the power needed by the amplifier. Power supplies take alternating current and convert it into direct current. First, the alternating current goes through a transformer, which steps down the voltage and increases the current level. Then a bridge rectifier--a set of four diodes that allow current to flow in only one direction--forces the output of the transformer to stay constant.
Remove 1/2 inch of insulation off one end of the red power wire and connect it to the positive power screw terminal on the amplifier. Remove 1 inch of insulation off the other end of the red power wire. Connect it to the positive output terminal of the power supply.
Remove 1/2 inch of insulation off one end of the black ground wire and connect it to the negative/ground screw terminal on the amplifier. Remove 1 inch of insulation off the other end of the black ground wire and connect it to the negative output terminal of the power supply.
Connect a small 12-gauge wire from the “remote” screw terminal on the amplifier to one side of the 12-volt switch. Connect a second 12-gauge wire to the other side of the 12-volt switch. The other end of the second wire must be connected to the positive output terminal of the power supply. Every amplifier has a remote terminal, which turns the amplifier on and off. When 12 volts is applied to the remote, the amplifier will turn on. The purpose of the 12-volt switch is to provide a way to turn the amplifier on and off without having to physically connect and disconnect the remote wire.
Plug in the power supply, switch it on and set the power knob to 12 volts. Turn the remote switch to the "on" position. The amplifier power indicator should be on, indicating the amplifier is ready.