This setup is in a boat without anything running other than the stereo.

The RF amp has a built in fan, when the fan is not running, everything is crystal clear, but after the amp heats up and the fan kicks on, which I believe has 2 speeds, I get a high pitch feedback through the speakers. You can turn up the volume and it drowns out the sound, but it literally sounds like a gnat on steroids sound coming through the speakers. I call RF Tech support and they were clueless on why.

Does anyone have any suggestions or exp with this. Once the amp cools down and the fan is off, no high pitch sound...