I've got a slight hiss that comes through my stereo. I've done everything I can possibly think of. I've replaced amps, replaced RCA cables and re ran them replaced EQ. Checked all grounds 100's of times. Has anyone used a noise filter? Do you have to buy one for each amp or is it just the lead going into the deck? <BR> <BR>Is there a better ground then using the block? Yesterday I noticed some alternator whine as well. I'm loosing my mind over this hiss.

this may be dumb but, <BR>are your gains turned up? or at zero?