Amplifier noise can be tough to track down! Sometimes it seems like you've tried everything, but that high-pitched whine or ugly clicking sound just won't go away. I sat down with a Crutchfield senior technical advisor for the inside scoop on how to get rid of pesky amp noise — and how to avoid it in the first place.


Grounding — think ahead to avoid noise.
Crutchfield tech advisors report that when customers call to ask for help with amplifier noise, the problem can most often be traced to an inadequate ground. But your system doesn't have to end up this way. Think carefully about how and where to ground your amp, and you're likely to come out noise-free.

Ideally, all your audio components should be grounded to the same location. However, many people choose not to do this, especially when it comes to the in-dash receiver. Who wants to run a ground lead from the receiver all the way to the amp grounding location, anyway? Well, if the receiver has a very solid ground in the front of the vehicle, you may certainly be OK grounding it separately from the amplifier. But if you're using your car's factory radio wiring harness, the in-dash receiver is probably grounded with many of the other dash components (turn signal switch, lights, etc), and those components can introduce noise into your audio system.

If your in-dash receiver and amplifier are grounded to different locations, a ground loop may occur. In this situation, the multiple ground paths can, in effect, act as an antenna for interference. The interference is turned into noise, and you hear it in your system.

Grounding your components to a heavy-duty bolt can help you banish noise from your system.

How can you avoid ground loop problems when your components are grounded separately? Ground your amplifier using as short a piece of cable as possible, and to as thick a piece of metal as possible. The longer the ground cable, the more resistance can build up — and that can spell noise problems. A common mistake is to ground the amplifier to thin sheet metal; this can introduce noise into the system, too. Crutchfield techs recommend that you ground your amp to a heavy-duty bolt, like a seat bolt or a seat belt anchor.

One important point about ground cable: it should be exactly the same size as the power cable that's going in to the amp. If you've got 4-gauge power cable going in, you should have 4-gauge ground cable going out. 8-gauge going in? 8-gauge going out. No exceptions.