Another audio question

[gr8fl4porsche]

I just switched amps this past weekend and now have a slight hum with the volume turned down. The CD player also makes a little noise when switching tracks.
Sounds like a ground problem to me. The amp is under the pass seat. I have the amp grounded using a 8 ga wire to the seat retention bolt and the amp sitting - not bolted down yet - on the metal floor pan.

What do you guys think?
Can someone explain 'ground loop'?

Aside from the low level noise, the old Soundstream 244 sounds real nice.

[lendaddy]

All of the wierd noises from audio systems are ground problems. I used to do $10k+ installs and I can tell you that nothing is more frustrating. I used to start by adding a central ground block that all the audio equipment connected to. Then run the main ground from that block to the battery negative direct. This does not always solve the problem but it is a good start. I have tried the capacitor thing to get rid of it too with no sucess. If your system is not too elaborate then just try moving the grounds to different spots cause the fact of the matter is you will eventually get lucky. Oh yea, some amps have poor design in this area and create their own ground loops from the boards to the case etc... IE some amps will always POP at power up. Hope this helps cause it can be a *****.

Just reread your post and you need to either attach the amp body securly to the car body or not at all. Just sitting on the metal is begging it to choose a ground point. this is what causes these problems, when you give a device more than one option to find a ground.