Persistent Whine in Cockpit Speakers

[aroos]

I posted this in the Technical Discussion forum and it probably should go here.


We have a C30 with the stock Fusion stereo system. There are 4 pairs of speakers including a pair in the cockpit. When the house power is on, even with the stereo off, we get a non-stop high pitched whine out of the cockpit speakers and only those speakers. It's there when music plays as well. To those with well preserved high pitch hearing it's very annoying when at rest in an otherwise quiet environment. We've had a very good boat stereo tech out 2 times and he's installed and then replaced a surpressor (?) on the output for the cockpit speakers. It works initially and then the whine returns. I've experimented at anchor turning off all power draws one by one (2 fridges, wine cooler, lights, etc.) but nothing eliminates the whine apart from turning the house battery switch off. The solar panel is, of course, operating so perhaps that's the issue. Any ideas?

 

[Levitation]

That you say a filter worked for a while, is puzzling.
Given that puzzling fact I would carry a spare battery into the cabin. Shut down the master switch to the boat and unplug the power to the radio/stereo and use two jumper wires to power it from the independent battery.
If there is no squeal from the amplifier itself then disconnect one wire from the solar panels to shut down the input to the solar charge regulator AND disconnect the positive wire from the regulator to the battery set to remove back feed power from the batteries, then turn the master switch back on (with the audio amp plugged back into the boat power) and see if that is the source of the interference.

If not then there are still two sources, your battery charger/inverter itself and and two unlikely - but possible - sources, the CO2 monitor and the sump pumps.

 

[aroos]

Thank you. I will get at it this weekend and let you know. While it is true that the surpressors halted the whine initially, th conditions may've played a role. The surpressors were installed and tested while the boat was in the hard (we have dry land moorage) on what I recollect were cloudy days, i.e. little input from the solar panel. I'm now wondering whether the source might be the secondary Fusion controller which is mounted in our cockpit.

 

[dpiano]

We also have the stock fusion system and have had a similar problem. It would only go away by shutting down house power, then starting fusion again, but would return after changing source from the galley remote. Ronnie had me pull the fuse labelled "memory" which is located by the house shutoff switch. This worked better, but eventually the problem returned. Ronnie is now sending me a new galley remote.