Question"I have a 2001 5.3L chevy silverado - Alpine head unit,equalizer, and 2 after market amps, also the speakers are all aftermarket as well / I have had this stereo for a long time - I have a whining noise through the speakers & it is very annoying w/ low volume. I have ran different RCA cables f/ the amps to the eq, and have checked ground(s) for the deck & amps - multiple times. I have changed alternators & just put in a brand new battery - no difference! I don't know if it's the amps or maybe age of the stereo - but I have heard of guys w/ these trucks have the same problem's w/ aftermarket stereo's - what does anyone suggest???"
AnswerHi Don,
As you're finding, noise problems like this can be very difficult to track down. With modern car audio equipment, engine noise problems due to grounding issues are fairly rare; today's manufacturers have learned to isolate the audio signal ground from the component chassis ground, so the notorious "ground loop" is much rarer than it used to be. These days, when I see a persistent noise problem, I'm usually going to be looking for a defective component, rather than a grounding issue.
Either way, the first step is to try to isolate the problem. You might try bypassing the EQ; connect an amplifier directly to the head unit, and see if you still get noise. Also, try running just one amp at a time--see if the noise persists when only one amp is connected, or if it only shows up when both are hooked up. One useful tool is a muting plug; this is just an RCA plug with the center conductor wired directly to the shield conductor. When you disconnect an amplifier from the source equipment, and connect a muting plug, you're intentionally sending a 0-volt signal to the amp--any noise that you hear then must be originating in the amplifier. You can then re-connect the amp to the EQ, and connect the muting plugs to the EQ's input, and so on. Once you have a better idea where the noise is originating, you can find a way to remove it.
Hope this helps!
Brian
