Grounding issues

[Turbinesurgeon]

I have some electrical issues which I believe may be due to poor grounds. The issue I had last season was never solved. I can hear feedback in the speakers while trimming the wakeplate as well as switching on the tower lights. The other day I started getting a very loud wine in the speakers and no music. It was terrible. I have 2 amps and I swapped the grounds and the problem followed the ground wire. I followed that wire back to a bus bar near the battery. Found some corrosion on that wire. Trimmed it back and put back on the bus bar. My question is if I should rethink how this ground is done on this boat considering the other issues I’ve had? I have cleaned all wires on this boat. The boat is a 2006 Supra that was outfitted by Earmark Audio by the dealer in Dallas.

In the pic you can see the top wire is a 4 AWG wire that comes from the bus bar in the helm. The 2 4 AWG wires on the side are for the amps. The other 2 8 AWG wires I’m not sure where they go, I suspect one runs the wakeplate. The bottom wire is 2 AWG and runs to the battery. I’m wondering if I should run that top wire from the helm directly to the battery bypassing the buss bar?

Sorry for the long post

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[MLA]

Nothing at all wrong with the use of a ground BUS. Its a great way to eliminate too many terminals at the battery post.

As to the noise, it may not make a difference moving the helm ground supply from the BUS to the battery, as they are still electrically the same. Are both amps ground to that BUS? Are both amps' positive cables going to the same B+ source?

I would consider removing that BUS bar in favor of a threaded remote battery ground stud. Put ring terminals on all those wise, sealed with heat shrink. This will prevent any further corrosion in those open cable ends.

[Turbinesurgeon]

Nothing at all wrong with the use of a ground BUS. Its a great way to eliminate too many terminals at the battery post.

As to the noise, it may not make a difference moving the helm ground supply from the BUS to the battery, as they are still electrically the same. Are both amps ground to that BUS? Are both amps' positive cables going to the same B+ source?

I would consider removing that BUS bar in favor of a threaded remote battery ground stud. Put ring terminals on all those wise, sealed with heat shrink. This will prevent any further corrosion in those open cable ends.

Yes both amps power and ground go to the same source. Your right changing the helm ground made no difference. Cleaning up the grounds for the amp made the high pitch squeal go away but still get feedback in the speakers when I move the wakeplate or turn on tower lights.


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[Branden967]

Yes both amps power and ground go to the same source. Your right changing the helm ground made no difference. Cleaning up the grounds for the amp made the high pitch squeal go away but still get feedback in the speakers when I move the wakeplate or turn on tower lights.


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Getting a good ground on a boat is a tad more difficult vs. your typical car stereo setup.

There are two basic problems with why your getting the engine whine or trim plate feedback. One is the ground which you've identified. I would try and isolate the stereos head unit from that ground buss bar by running another ground wire back to somewhere on the engine's block, away from the alternator and any other grounded wires. Secondly if that doesn't totally get rid of the noise they make ground isolators that connect between the RCA connectors and the amp. I haven't personally tried one, but a lot of friend have with good success. They look something like this;

https://www.amazon.com/Earthquake-Sound-GLI-200-Kleaner-Isolator/dp/B07Z5SKRMR/ref=sr_1_4?crid=25X5A1U3PE6HJ&dchild=1&keywords=stereo+ground+loop+isolator&qid=1616513195&sprefix=stereo+ground+loop+%2Caps%2C214&sr=8-4

[MLA]

by running another ground wire back to somewhere on the engine's block, away from the alternator

Sorry to throw a wrench in your cogs, but the alternator grounds directly to the engine block through its housing.

GLI's should be an absolute last resort for resolving ground loop, but you first need to determine ground loop is what you are dealing with. Most people do not understand what ground loop in the audio path is, and therefor, thinks its only a result of the audio component's DC ground.

The feedback noise from the wake plate and lights, is not ground loop. If I was going to relocate a ground to the block, it would be the helm BUS. But again, im not sure this will resolve this in the audio. Search "pop when using trim tab". I know some info has been shared on this forum.

[Turbinesurgeon]

Thanks for all the help. That gives me some direction. I’ve been trying to hunt this down off and on during the last two years


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[Branden967]

Check out this video, some good info that my be very helpful.

https://www.youtube.com/watch?v=Q8dpucdxs6Y

https://www.youtube.com/watch?v=eIB4IaNWS_M

[Turbinesurgeon]

Check out this video, some good info that my be very helpful.

https://www.youtube.com/watch?v=Q8dpucdxs6Y

https://www.youtube.com/watch?v=eIB4IaNWS_M

That’s some good stuff. I’ve already installed the capacitors on the trim switch and that didn’t help. I’m going to try and run shielded RCA cables to the amps and see if that helps


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[HFarr]

Did you get the ground issue solved? I installed an amp and tower speakers on a boat I had previously. I grounded the amp directly to the negative battery terminal. I had a slight buzz that I could never stop. After some reading, I finally re-ran the amp ground to the same ground bus bar the radio was grounded to and that cleared it up instantly.

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[HFarr]

This is some good information


https://www.lifewire.com/whining-noise-when-i-use-aux-input-534592

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[Turbinesurgeon]

Did you get the ground issue solved? I installed an amp and tower speakers on a boat I had previously. I grounded the amp directly to the negative battery terminal. I had a slight buzz that I could never stop. After some reading, I finally re-ran the amp ground to the same ground bus bar the radio was grounded to and that cleared it up instantly.

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Thanks for the info, I did move the ground to the same buss the amps are grounded to with no change. I installed some triple shielded rca and reset settings on the amps which seemed to cut down on the feedback a bunch but I can still hear when you start trimming or let go of the trim switch. Same with the lights but way less noise so it is an improvement.


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[HFarr]

Hmmmm.... Maybe some ground isolators might be worth a try. They aren't expensive.

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[qwertykerr]

Hmmmm.... Maybe some ground isolators might be worth a try. They aren't expensive.

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if you run the ground of your head unit directly to where the ground wire inserts into the amp you remove the loop and will eliminate the noises. Worked for me. the blower noise was the most noticable... but the alternator whine was bad too. Both gone once i did this. The Rockford Fosgate actually suggests this. As did another forum.

Right now i still do have the issue of a slight white noise from the speakers. The 6 inch you can barely hear it with volume at 0. The wake cans it's very low volume. Trying to solve this...

[MLA]

As noted earlier in this thread most people to not understand what ground loop is, thus they only focus the DC B-. Takes two to tango, so dont ignore the B+.

[HFarr]

I think it was already suggested to make sure amp and head units are sharing the same ground point. I had that problem on an older boat, and doing that took care of it. However another post on here with white noise in the speakers recommended making sure you only have ONE battery selected if you have a multiple position switch. That seemed to solve their problem with noise.

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[MLA]

I think it was already suggested to make sure amp and head units are sharing the same ground point.

So different B+ points are ok? Either way, theres a potential for a voltage differential.

[Holdmybeer]

If everything is isolated to 1 battery, all grounds made at single point (i.e. bus bar or battery terminal), all positives are made at single point, RCA's replaced, then it is time to start thinking about the unit itself.
2006 Supra, was this original or replaced over a decade ago?
Do you have a transom remote? Is it corroded from being in water 90% of the time?

TEST
1. Can you get a 3.5mm headphone jack to RCA adapter (or lightening connector to RCA, or usb-c to RCA) and plug a device directly in and play music? The amps will work and you should hear music. If the noise is gone, the amps, rca, etc. are all good. Turn the volume on device all the way up. If it still happens, we need to start looking at the amps.

2. Now while still using the handheld device, use the device charger and then 12V port near the radio (assuming it has one). If the noise returns, you have a ground loop or power problem. If it does not come back, reconnect the head unit and see if it comes back. That would point to the radio.