Getting feedback and engine noise

Just over the last few weeks I developed a very annoying engine noise that whines with the increase in rpm of the engine. With stereo on but boat off im getting slight feedback/whistle - I can tolerate that but would still like it gone. Once the engine is running im getting very loud feedback, predominatily through the tower speakers. This all starting happening out of nowhere.

First thought was it was a bad rca or loose Y adapter somewhere between the WS-420 and the two Syn 4's. I unplugged them all and ran new ones - same problem.

Next, I thought the fans on the amp rack could be causes the noise so i unhooked them all - didnt help.

I also ran a jumper ground from one amp over the ground on the WS-420...did not help.

My set up - four Syn 1 & three Syn 4.

I ran out of time last night to look into much further. What do you guys think?

This can be a real pain to track down in most cases. Definately sounds like a grounding issue. Something probably came loose over time. Have you checked all the grounds (connections) on your batteries? start by making sure every ground connection is tight.

a ground inside one of your pieces of equipment may be loose ( over time). start removing pieces of equipment from your system one at a time and see if it's bad.

Dont' forget about the head unit.

I had a similar issue several years ago. It ended up being my cd player. Changed it out and the problem went away.

i bet the inverter for the fog machine and cottage cheese cooler (some call it a refrigerater) is causing most of that noise. You should remove that and try, because fog machines are gay, and we dont want no HAWGS

thanks UN - i will try this and report back.

Brian,
Because you have HLCDs on the tower the noise would normally be more pronounced from the tower. Shut the tower down and confirm that the same noise is in the in-boat speakers.
Completely eliminate the EQ from the signal path circuit and bypass it with an RCA and barrels.
Then completely eliminate the source unit from the signal path circuit and use a self-powered ipod direct.
Narrow it down to a single amplifier and ipod only if you have to. If a single amplifier and an ipod have the noise using an independent test speaker and wire then you have to start looking at boat issues outside of the audio path.
Using a systematic process of elimination, at some point you have narrowed down the entry point of the noise or at least where a ground or supply loop may have developed.

David
Earmark Marine

David - There is no engine noise with the towers unplugged at the EQ and amp. There is still a faint hiss but i think this due to gains?

Brian,
So if I understand correctly you are saying that the noise is introduced upstream from the amplifier in the signal path...which is typical. Run the EQ without an input source and see if the noise is back. If no noise then run an ipod on its own battery power into the EQ and without the HU. If no noise then re-connect the HU. Run the HU directly into an amplifier totally bypassing the EQ. Try running the HU speaker level out into a speaker level input on the amplifier instead of using the HU RCA preouts. You could have a bad preout section on the HU. The point is you can isolate and eliminate each potential cause.
None of this will be particularly revealing until you confirm that the HU, EQ and any other in line processor references the identical ground and supply as the amplifiers. Also, try grounding the EQ and HU chassis as well as the ground wires.

David
Earmark Marine