View Full Version : Ground loop question?

06-14-2009, 09:45 PM
How do i know if i have a ground loop problem.? I have a slight whine at very low volumes with just the stereo on and the boat running. turn up volume and goes away

06-15-2009, 09:54 AM
Easy fix: Just keep it cranked up! :D

06-15-2009, 07:14 PM
razz, newty you out there??

06-15-2009, 08:52 PM
Make sure that the amp(s) and the head unit is all grounded together. For example, If you have two batteries, put all the stereo equipment on the same battery, ie the ground. This will eliminate the noise you are hearing. I had the same problem with my stereo and this fixed it. I hope this helps. Let us know the outcome.

06-15-2009, 10:16 PM
Sorry JM, been busy trying to find a job!

Tazz is correct, ground loop issues generally occur when multiple grounds are used, example amps are grounded to different sources. I like to to use distribution blocks with one input and multiple outs so i can have all audio gear powered & grounded to the same sources.

06-16-2009, 06:51 AM
Tazz, Razz

thanks guys, while i am still working through my isolator issue, I seemed to remember that the amp was grounded to the deep cell an the accessory bar was to the starting battery. I need to move the one for now and the get the distribution blocks for ease and a future Amp :D

Razz good luck in the search

06-16-2009, 07:56 AM
I bought these for my boat
I had ordered two of these. One for the ground and the other for the positive. everything on the second battery, that needs power, goes to these terminals. Basically, I wired all my accessories to the second battery.

Sorry to hear about the job lose. Not sure if Northern Calif is just as bad as Las Vegas. My business is very slow right now. I am down to one guy. Also, not sure if it is a good time to start another business, but I have to give it a shot. Good Luck with your search

Tazz (Mark)

06-16-2009, 09:55 AM
great idea! thanks.


08-01-2009, 10:50 PM
still got the buzzing noise, I put the amp ground on the accessory ground to the house battery. I still get the noise when any of the accesories ( bilge, blower, balast pump, engine are on) perfectly fine when engine off.

Help??? any ideas

08-02-2009, 02:25 AM
This is what i would do now that your pretty sure its not the ground loop. It could be a bad ground or a floating ground in a component.

This takes time to rewire the system but it helps track it down.

How many amps are you running?

Is the noise in all speakers on multi amp system?

If the noise is only in certain speakers say cabin or tower then unhook that amp and see if the noise goes away. If unhooking this amp causes the noise to go away then that amp has a back ground, connection or bad internal ground.

If this doesnt work then try switching your RCAs to see if the noise moves from one set of speakers to another. Switching the RCAs will help identify if the deck has noise on one of its preouts.

This helps show if the noise is from your deck or not.

If you do all this and nothing seems to change the noise or change its location then you have to eliminat items from the cercuit.

Wire up the speakers to only your Deck. Noise? Bad deck. Bad deck ground. No noise? Good deck

Noise in the system with only a deck wired also tells you the amps are good and not the problem.

No noise in the deck and then you wire 1 amp back in the loop and if you get noise then the amp is the colpret and you have a floating ground in the amp.

If all this moving things around still doesnt work and you have noise no matter what you do and you realy dont think its the deck then you have a few other things to check.

Check all the spark plug cables on the engine, if the shielding is old or cracked it will cause noise in the system if its a weak ground.

Check all the connection in the boat near any stereo wires or components including the toggle switch by the steering wheel.

08-02-2009, 09:24 AM
MMandley i will check these procedures out.

I have only one amp a 6 channel jl.
my bow speakers are wire through the HU and don't seem to have the buzz. i will double check.

??? when i put my dual battery system in the main ground wire to the engine was too short so i attached it to the house battery 1st and jmup it to the start battery. could this be the problem? also keep reading about the stereo rocker switch can cause problems. I also have and pac lc1 for the towers, like an eq but does not have a ground.

08-02-2009, 07:05 PM
went to the boat this am and checked out the pac lc1 and that is where the buzzing is coming from. ( i switched it from cabins to towers and the buzzing sound moved) Also it looks like the power and ground travel with the pac lc1 rca cables for about 10" in the same conduit. anyone know if this is the problem.

08-04-2009, 04:53 PM
Yes that can cause a problem. Running your RCA as well as speaker lines the length of a power and or ground cable can and generally will cause noise. If you can route it outside of the tube then do that. If you cant then you need to upgrade the RCA to a very high end type that has a high quality shielding.