Speaker Whine Coming from Perfect Pass??

[squeeg333]

Hey guys, I have a new issue I'd like to run by ya.
I installed (replaced) my tower amp with a kicker 200.4 and installed a new 700.5 to run my cabin speakers and an eventual sub. I installed Polk DB's in the cabin, and they sound great. However, they sound great when the boat is off. :(

I was finally able to get the boat wet this weekend, on a nice blustry cold spring day, and was syked to get the tunes rocking. Well, I come to find out that when the key is on and/or the engine is running, I've got a high pitched whine in my speakers. I assume it was also coming from the towers, but didn't check that. Now, here's the kicker:

I put the key to the on position, and everything powers up, Perfect Pass does it's start-up screen saver thing. The high pitched noise starts when the perfect pass display turns on, and then the noise goes away (once the "into" is done on the perfect pass). This is for when the key is just in the on position.

Now, when start the boat, the noise will pick up at the same point, when the perfect pass display turns on; however, when the "intro" on the perfect pass goes away, the noise stays (again, when the engine is running). The noise doesn't increase as the RPM's increase, but seems to track the volume of the speakers.

I assume this is some sort of grounding issue. I do have my speaker wires near my power wires on my amps, I know this isn't good, and I plan to move that. I also plan to replace the RCA's with better, shorter cables. However, I am baffled why I seem to be getting feedback from Perfect Pass. I have PP Digital Pro, and it's an 08 LSV. I only have 1 battery (at least right now, in the planning stages of a dual battery install), and all my grounds on my amps go to said battery. I did not check to make sure they were tight on the binding post however.

I hope I answer some of the questions you guys might ask me, so, put your thinking caps on and let me have it!!
Thanks in advance guys!

[brain_rinse]

Sounds like ground loop noise to me. Try grounding your headunit directly to the battery. There is a 3-wire connector behind the headunit (red/yellow/black). In my opinion the yellow and black should be hooked to the same power source as your amps, which in your case is directly to the battery. The red goes back to the stereo switch at the helm and can stay as wired from the factory.

[squeeg333]

Brain, thanks for getting back to me on this. I made the ground for the radio (the one coming from the factory wiring harness) go straight to the battery. Should I also make the yellow go to the battery? I found that you were totally right, a grounding issue. I reduced the gains on my amps (they were both set to full gain) and I reduced the whine. However, it is still there. I plan to put a dual battery in soon, and have read that should help, but in the mean time I am looking for advice.

I've read a lot about this ground loop issue on others boats, and there's a lot of different schools of thought. I guess I am curious what other people have had success with in the past with this problem? The noise comes thru all speakers (tower and cabin - which both have seperate amps), and increases as the gains are turned up. I think I didn't notice it before because I think the gains were turned low on the original setup (though I'm not sure).

Anyone have any good words to the wise on this? I was thinking of getting some ground lop isloators for my RCA's, but was looking for other options also.