Interference

[Bamatique]

I have a 2005 SANTE 210 and my original amp went out. When I replaced it I now have interference(static) when the motor is on and idling. Everything is clear with the motor off or in higher rpms. I assumed it was a loose ground but I couldn’t find anything. Any suggestions on what it might be?

[core-rider]

Ground loop issue picking up noise from the alternator... all stereo equipment (HU, EQ, amps) should be grounded to the same battery. I can say in 2003 it was not that way from the factory. Once it put it all on the same battery the noise went away.


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[MLA]

I assumed it was a loose ground

The B+ is just as important.

May be time to upgrade the RCA.

[bturner]

It always amazed me how the wiring could get so bad on some boats when they (I hope) employ Electrical Engineers to design the systems and wiring harnesses for these boats. A lot of times it's just a cost cutting exercise that ends up causing these problems but sometimes you just have to wonder. Add previous owner's "upgrades" and all bets are off. This last boat I've owned looks pretty solid however I do have some questions regarding the larger circuit breakers and distance to the battery but I don't seem to have any issues so far.

So past the rant.... The early 2000s were a real transition period for many boat manufactures especially on the sound system side. We experience a soft economy and every aspect of a product build were tightened up. That and most didn't account for the 1000 watts of power that would be fed to the multi amp systems that would be later installed later. Thus the power feeds and electrical power designs are woefully under sized for the task at hand. One only need look at all the issues with gauges to see how inadequate the power/grounding and electrical noise suppression was on these model years.

As to your issue.... Whine or noise in the sound system is typically a symptom of poor grounding causing a ground loop but as stated source power in general should be closely looked at. While age or modifications by a PO may play heavily into the source of the issue you may want to consider upgrading the power and grounding circuits to the battery along with installing bus bars to tie the circuits together. As stated above all your stereo components (amps, head units and any other powered components) should all be tied to the same bus and have direct access to the battery to ensure the same power and grounding potential. Examples of what I've seen in boats from this build period are undersized power/grounding cables, poorly crimped connectors, the lack of properly install bus bars and multiple direct runs to the battery terminals, all of which could cause the issue you're experiencing.

Probably one of the better "good example of a bad example" I have is from an 07 MasterCraft I worked on. This one I was told had a $3K stereo installation from a Professional Marine stereo shop that I've shown here before. Guess which is the before and after.

In the end if you don't get the basics right you'll end up spending hours chasing issues that may show up intermittently.