Hi,
Interference is a nasty problem. Since you stated that the New system has
the problem but the Old system did not here are a few tips.

Some things you might have missed in your checking.
If you are plugged into shore power the buzz may be from your battery
charger.
If you have a inverter it may also cause a buzz.
To fix either of those or just to shotgun the problem, install a power line
filter.

You can also pick up a buzz if any line is along side a AC line, the new
wiring may be to close, rerouting may be needed.

You may be picking up noise from something on the dock or a neighbors boat,
take the boat away from the dock and check it out.

If nothing else help, then try shielded wiring. Use it between the units
and to the speakers.
Run a ground wire between each unit and to battery ground in a daisy chain.

Mike

"Chris" wrote in message
ups.com...
Hi I'm new to the group and a newbie at wiring stereos so please bear
with me. On my boat I installed a new Kenwood receiver and a new Sony
CD changer. Connected to an older (6 yr.) Kenwood equalizer ans Sony
3040 that's the name amp. I've installed new speakers outside, checked
and upgraded all my speaker wires and connections but there is a buzz
in both sets and wasn't there in the old system. I've connected a
ground wire from the stereo power neg busway to a copper strip which
runs all thought out the boat. I've checked the resistance on the
copper by setting my meter to 20K touch both prongs together and get
0.03 rating. I then placed both prongs on the copper wire and the
resistance reads 0.03 but still the buzz. If I disconnect this #16
ground wire it of course gets louder. I've tried a heaver ground wire
#8 no change still the buzz.The power wires +/- to the amp are #8


Where next do I get better RCA cables than Radio Shack and if I need a
separate ground for the amp where do I attach it....to one of the
mounting screws holding the amp to the boats wood interior? The buzz
is making me crazy trying to get rid of it in both the radio or CD's.
I've also turned off at the panel board all other items, no motor and
still the buzz. Today I cleaned and tightened all battery connections
you guess it still there