Stereo Grounding issue

[Scott Cunningham]

I have a 2003 Sea Ray 200, and it has the factory installed Stereo/CD player. When sitting at the dock or afloat it plays fine. When the engine is on I get a high pitched electronic interference thats directly linked to engine RPMs. Pretty sure I have a grounding issue. Any ideas?

Second note..... What are your thoughts to the cost/difficulty of pulling the existing 2003 era stereo and replacing with a modern Bluetooth capable version.

 

[Scott215]

The stereo in my 215 weekender is grounded directly from the battery into the cabin I don't know what you're ground is but double check or maybe add one see what other people say

 

[Scott Cunningham]

Where does grounding hook in on back of stereo? I’ll run a wire from there to battery. Which terminal should I hook to?

 

[Scott215]

Should be black wire.to neg terminal

 

[Wylie_Tunes]

1) did the just randomly start or has some audio equipment been replaced/added?

2) are the speakers powered by an external amplifier?

3) Upgrading will not be plug n play. If you have any wired remotes, then they would become obsolete and would need to be upgraded, along with their extension cables, that are compatible with the new unit.

 

[ttmott]

There is a good chance the engine's alternator is failing. If the AC to DC rectifier fails the alternator begins to put AC current into the DC system. And, that will definitely put noise into any audio system; called "ripple".
It's an easy test to see if this is happening. Put a good quality Digital Volt Meter on the alternator B+ and Gnd. Put the range on AC volts millivolts. See what the voltage is when the engine is not running - it should read 0 volts.
Now start the engine and set the RPM to where you get noise on the audio system. If the DVM is reading more than 300 millivolts then you know the alternator is putting ripple AC voltage on the DC system.
Stop the engine and disconnect the Bat+ wire from the alternator then run it again - is the noise still there?

 

[Skybolt]

@Scott Cunningham do you have external amps? Either way as mentioned above it could be alternator noise. A simple power filter might fix what your hearing and if external amps a ground loop filter will help.

Something like this will help if the internal amp is being used. Many choices but this falls in th eleast expensive options: https://www.amazon.com/Pipemans-Installation-Solution-Suppressor-Eliminator/dp/B07HZ4RSS7/ref=sr_1_3?crid=34PJ4YR9TPAYM&keywords=stereo+power+filter&qid=1682256785&sprefix=stereo+power+filter,aps,251&sr=8-3

If external amps then this is a great option: https://www.amazon.com/Isolator-BOSS-Audio-B25N-Systems/dp/B000LP4RMG/ref=sr_1_3?crid=31YS038M8RGPG&keywords=boss+ground+loop+filter&qid=1682256943&sprefix=boss+ground+loop+filter,aps,315&sr=8-3&th=1

 

[Scott Cunningham]

Lots of great inputs! Stereo came with the boat. Its been this way sinec we bought it. No components have been replaced, but I'm considering that now to add Bluetooth capability and play music off my phone.

I'll have to check out the alternator ripple issue. Thats a new one on me, but it makes sense because the buzz happens only when the alternator is spinning. Stereo is fine when engine is off. It buzzes badly when engine is on, and buzz increases with RPM.

 

[Chris-380]

This is great info
Thank you!

There is a good chance the engine's alternator is failing. If the AC to DC rectifier fails the alternator begins to put AC current into the DC system. And, that will definitely put noise into any audio system; called "ripple".
It's an easy test to see if this is happening. Put a good quality Digital Volt Meter on the alternator B+ and Gnd. Put the range on AC volts millivolts. See what the voltage is when the engine is not running - it should read 0 volts.
Now start the engine and set the RPM to where you get noise on the audio system. If the DVM is reading more than 300 millivolts then you know the alternator is putting ripple AC voltage on the DC system.
Stop the engine and disconnect the Bat+ wire from the alternator then run it again - is the noise still there?

 

[Wylie_Tunes]

So with no newly added or replaced audio gear, a failing alternator would be at the top of my list.

 

[hblock72]

My boat had the alternator whine when I bought it new. It came though the amp, which only powered the two front speakers. The rear speakers where powered by the head unit. It was only a two channel amp. (still scratching my head over this factory set-up) Anyway, I first noticed something fishy after taking delivery of the boat because I had to skew the fader way towards the front to get even sound out of the speakers. After looking into it further I noticed the gain on the amp was turned all the way down, which masked the alternator whine. Guess this was the factory way of getting it to pass quality control ;-) After adjusting the gain, a neutral fader setting produced even sound out of front and rear speakers, but produced the alternator whine when the engine was running. I took it back to the dealer to have it fixed under warranty and they put one of the ground loop isolators on the RCA jacks of the amp, which did fix the issue. I always thought it was kinda fixing the symptom and not curing the root cause, but it's worked for the last 15 or so years. I've been wanting to upgrade the entire system, but it works well enough that it just hasn't been a priority all this time.

 

[Wylie_Tunes]

@hblock72
Yes, those GLI's do mask the issue, not resolve it. I wonder if that amp was added post-build at the dealer level. Likely added by a boat mechanic that does not understand the relationship between audio components and voltage sources. The amp got wired to the easiest/closest power/gnd BUS source, the installer came across.

GLI's can also attenuate the audio signal, so they should be a last resort, not the first.

 

[hblock72]

Wylie, The amp was a factory option that came as part of the wakeboard package. Along with the addition of the wakeboard tower and tribal graphics you got an audio upgrade. The audio upgrade consisted of a Clarion M455 instead of the base M255, an additional two speakers in the bow, the amplifier, and a wired helm remote. The wiring diagrams in my manual show both the base setup and the upgrade.