Going to plug in the shore power,turn on the built in battery charger for a few hours,then see if there is still feedback. If so, it is not a battery problem.

http://www.installdr.com/TechDocs/999502.pdf

My guess is a grounding issue

Thanks,Kevin. My thoughts exactly.Kind of like if I pay a plumber what he asks to fix my toilet and it still doesn't flush,it's his problem to make it flush,not mine.

Just remember that battery charger will most likely put a ac humm over the stereo. Turn it off when testing sound quality. With the batts fully charged you should get some time to test before they flatten a bit depending on how many amplifiers and wattage.

If You Don't Find A Problem With The Rca Cables Or Power Source Pull The Amps And Have Them Bench Tested. It's A Possibility That The Amps Or Amp Has A Bad Power Supply.

It sounds like you have a "ground loop" issue, which means two grounds with different resistances. Try grounding the radio with the amplifier ground. For temporary purposes, run the stereo ground wire straight to the amplifier ground terminal at the amp. If the noise goes away or gets better then that is the problem. You don't have a voltage issue.

Thanks for the help guys. Another example of the power of OSO. Will let yall know what my stereo guy finds. Thanks.Robert

It's not the batteries, make sure you have a solid CLEAN ground.

Wow, so caps magically create voltage???