I have a couple more questions.
In an earlier post you stated " But the biggest issue is that all audio electronics are wired to the output post of the dual battery switch and do not go battery direct. This totally eliminates any possibility that the amplifier could access one battery and the source unit could access the other battery (which will often have varying voltages)."
Then you stated " When using a dual battery switch, the engine alternator/starter feed, helm buss, and all stereo equipment should go to the dual battery switch output post. Nothing but a bilge pump/float switch (if applicable) would go battery direct."
So I am confused on this point.
If all audio equip has to go to the switch post, How am I supposed to get it all to the same B+ point. Wouldn't the switch determine what battery I am getting the power from?
Here is another thing which may spark an answer. When I switch the dual switch to "ALL" instead of 1 or 2, the noise is half what it is if only set to one of the other. The other issue is that when I turn up the volume, about half way up, the noise seems to go away. Maybe because its being drowned out but it goes away.
Last you mentioned the same ground spot. Which I do not comply there. Currently I have both batteries grounded to the transmission. I am going to run a ground cable from one to the other and then to the switch to see if that fixes it.
When I was a child, I used to talk as a child, think as a child, reason as a child; when I became a man, I put aside childish things.
1 Corinthians Chapter 13 - 11