Why is my amplifier grounding out on my computer?

Maheriano · 08-29-2008, 11:03 PM

The Preface: I was taking a sharp turn today and my sub violently slammed into the other side of my trunk making a loud bang. After that I had a loud ground loop in my system. The way my system is in my trunk is I have a piece of wood as a floor in my trunk with 2 amplifiers and 1 computer lined up side by side on the front (bumper side) of my trunk. Behind those on the seat side is open and that's where the subwoofer sits. Usually it stays in one place but it has the possibility (I know now) of moving side to side. It is very unlikely (though slightly possible) that the subwoofer even touched anything besides the wood. I made a ledge that sits above the amplifiers/computer so that nothing can hurt them.

Today: I just took a look at it and it seems, for some reason, that my amplifier is using the RCA cable to ground itself out on my computer, creating noise interference. Here's what happens:
1. Plug RCA cables into amplifier with other end dangling, nothing happens
2. Plug RCA cables into amplifier with other end in computer, amplifier turns on.
3. Plug Ground Loop Isolator RCA cable into amplifier, plug other end into computer, nothing happens. I guess the isolator filters out the ground.
4. Plug different RCA cable into amplifier with other end in computer, amplifier turns on.
5. Remove RCA cable from either computer or amplifier, amplifier turns off.
6. Plug RCA cables into amplifier and touch other end off grounded metal object, amplifier turns on.

My amplifier is 2/4 channel and it only happens for one set of RCA. If I plug the RCA cable into the REAR ports on the amplifier, nothing happens. If I plug them into the FRONT ports on the amplifier, the amplifier turns on.

So I'm not sure why but it's grounding out there. If I leave all RCA cables unplugged, everything will come on except that amplifier. It is grounded properly on the body just as it always was, I checked that.

pancit175 · 08-31-2008, 05:20 PM

I'll tell you what I told the other guy who asked this same question on here. The only time I've ever seen this problem, when it was not a ground wire failure or misconnection, is where there was problem with the amp. It must be a problem of the circuit board of the amp not making a connection to the ground terminal of the exterior of the amp. Or more specificly, it could be a problem with the ground circuitry on amp's circuit board. The case that I saw this happen was the on the printed circuit board, there was a break of printed ground that would not connect the exterior ground terminal to the internals of the amp because of that break. The solution, although temporary, was reconnecting the break with well placed solder joints onto the circuit board. I did instruct the owner that he this is only a temporary fix and that he should get a new amp as soon as he could afford one.
And the possible reason why you are not getting one set of RCAs to allow the amp to turn on is the fact that it may have broken the ground wire in the RCA because of too much current being ran through it.
So all things considered, get a new amp and new RCAs.

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