How to Modify a Car Amp

Doing some modifications on your amplifier will boost the volume and clarity of your stereo system.

Amplifiers produce and enhance sound quality through all volume ranges. Elaborate speakers systems, particularly ones that contain sub-woofers with low-end bass frequencies, draw a tremendous amount of power, which requires signal and flow amplification. Amplifiers come in many designs and output ratings, either internally mounted or available as external add-ons. Modifying an amplifier requires some specific adjustments and possible change-outs.

Difficulty:

Moderate

Instructions

Things You'll Need

• Stereo and amplifier owner's manual
• Wire (8 or 4 gauge)
• Contact spray
• Rags
• Socket set (1/4-inch)
• Ratchet wrench
• Wire strippers
• Screwdrivers

1. Inspect all of your wire connections, starting from the back of the amplifier and tracing them through any in-line fuses. Use a small socket to disconnect eyelet wire connectors on the back of the amplifier, then clean the connections with contact spray. Wipe the connections with a rag and replace the retainer nuts. Tighten the nuts with a socket. Check the in-line fuse on the main battery supply wire. Make sure the screw connectors tighten firmly and the fuse has a good filament.

2. Replace undersized gauge wires that do not meet the manufacturer's wire diameter (gauge) specifications. For high output amplifiers, you should use 8-gauge or 4-gauge wires. Inspect the main ground wire, speakers wires and battery power input wire for insufficient gauge. Replace them at their connection points by pulling the spade connectors or unscrewing the retaining nuts with a socket. Use the appropriate spade or eyelet fasteners to connect the new wires.

3. Turn your ignition key to the "On" position. Use your stereo amplifier owner's manual to locate the adjustment screw on your amplifier responsible for "gain" control. It might be a twist lever or a screw slot. Turn the gain control switch all the way down. Turn your stereo on to a clear, powerful receiving station that has excellent reception.

4. Turn your stereo volume control to 80 percent of maximum volume. Slowly turn the gain control switch on just until you begin to hear distortion. Turn the gain control down very slowly, one notch at a time, until the distortion goes away and then stop.

5. Refer to your stereo amplifier owner's manual for the location of the high-pass and low-pass filter levers. Temporarily disconnect the rear speakers to your vehicle by opening the panels with a screwdriver and pull the speaker wire spades. Turn the stereo on and adjust the high-pass front speakers, for the best frequency and tonal range.

6. Remove the front speaker panels with a screwdriver and disconnect the speaker wires. Adjust the low-pass levers for the rear speakers, attaining optimum frequency and tonal range.

Tips & Warnings

• Clean your power antenna with steel wool and lubricate it with a fine machine oil, so that it moves up and down within its full range. The amplifier will not be able to clearly boost if it receives poor reception from a dirty antenna or loose antenna mount.

References

• Mademan: How to Modify Car Amplifier
• Crutchfield: Car Amplifier Glossary
• Crutchfield: Car Amplifier Shopping Guide