I think he's assuming the cables are fine because the other amp worked with
it. Not an unreasonable assumption. But I've seen stranger things happen.
It's not at all uncommon to get noise out of a perfecty working amplifier or
signal processor, even when plugging in another type gets rid of the noise.

"Soundfreak03" wrote in message
...
No, I did not try messing with the head unit ground, thank you for
suggesting it. What about the head unit ground would make the noise thru
RCA's but not hi-level inputs, even when the engine is off? A ground
loop?
As I said in my first post, any info is appreciated.

Ground loops are funny sometimes. The addition of the RCA's could actually
cause the ground loop, your HU could be attempting to use those as a
ground. Or
you could have bad RCAs with a break in the cable somewhere. Try the HU
ground
and try a different set of cables. Pay attention to the results of each
and
then in combination, that way if it doesn't work you can tell us what
exactly
happened.

Les