Buzzing in Speakers

[DanW]

Hello,

I am hoping someone out there can help me with loud buzzing in my speakers when any 12 volt items are running. There has always been a very small amount of buzzing, but it was so low I didn't worry about it. Last weekend, I removed the battery cables from the house batteries. When I reconnected them, the buzzing was extremely loud. (I did not change any wiring.) So loud, I was afraid it would damage the speakers. After doing some testing, I determined that the buzzing is occurring on all 6 speakers and gets louder the more 12 volt items are running. The fridge is dual voltage - no buzzing when it's running on 110, but obnoxiously loud when running on 12 volt.

I searched the forums and tried a couple of ideas. The amps were wired directly to the batteries, so I wired them to the 12 volt distribution panel instead. No change on the buzzing. I purchased a ground loop isolator, but that just reduced all sound to the speakers to almost nothing.

Details: 1988 340 Sundancer; Pioneer head unit; 2 amplifiers (1 runs the cabin; 1 runs the cockpit); 6 speakers; no subwoofer

The head unit is currently wired through the helm. Somebody suggested wiring it directly to the battery? Does that sound like the next step? I assumed the amps were the source of the buzzing, but could it be the head unit? This is my first post on this site, so I'll just apologize now for any newbie mistakes!

Thanks,
Dan

 

[wilytemptress]

When you say you moved the amp wires did you move the ground wires as well. Sounds like a bad connection somewhere.

 

[Xplicitlnck]

Ground the amps and hwead unit right to the battery as well as the power cables for the amp directly to the battery. Also make sure u didn't fasten any power or ground cables for the amp to any other existing 12v cables. They will transfer noise interference. Good luck

 

[skibum]

Your post does not indicate whether this happens all the time, of just when you are running on shore power or generator.

My battery charger introduces some buzz into the stereo. If I am not on shore power - no buzz.

 

[mrtopgun]

You have a grounding issue. Clean your grounds up, with battery cleaner, and put back on and use Diyletric grease. Grounds will jump into power lines and create a hum. Your original hum was probably coming from your battery charger/inverter or from your alternator. Very common. try cleaning up the ground first. A ground will find the path of least resistance, just like water. Good Luck

 

[DanW]

I did move the ground wires as well. And while I haven't tested to see if it happens with the generator running (I would assume it wouldn't matter), I have tested it with shore power connected and not. There was no difference.

Thanks, everyone, for your suggestions. I will be trying them all this weekend. Plus, a few additional ideas from the local car audio shop.

Dan

 

[skibum]

If you know that it does itm with the shore power disconnected and the generator off, then you definately have a ground problem.

Happy hunting!

 

[DanW]

After doing some testing this past weekend, I'm pretty sure the amplifiers themselves were the problem. The previous owner had installed 3 amplifiers and a crossover. (There used to be subwoofer.) so, I removed all of it and wired the speakers directly to the head unit with no buzzing at all.

I am running 6 speakers which I know could damage the head unit. I will purchase a new amplifier and install it, but I really think it was just the old amplifiers that had bad (or damaged) grounds in them. If not, at least I've narrowed it down now.

Thanks again for everyone's help.

Dan