I just purchased a boat that has a nice sound system in it but has one issue. It has a constant buzz sound to it and it is annoying when listening to music at a low volume. The buzz stays the same no matter how high or low the volume. It exists even when the boat is not running. The system is an Alpine deck, Alpine Amp and Memphis Audio speakers including one 10'' sub.

What could be the issue?

7/30/2008 1:42:01 PM

First thing before you go checking all the grounding an such...turn down the output from the Line out convertor on the amp and see if the buzzing goes away

7/30/2008 1:51:08 PM

See that is what I thought it was from the beginning but I couldnt find any settings on the amp that would allow me to turn the output down....I thought all amps had that and was confused when I could find it on this one.

Is that something that should be on all amps?

7/30/2008 5:02:23 PM

maybe a wire is unshielded...

7/30/2008 5:18:13 PM

you've got an unshielded power wire running in parallel to wires coming off of your amplifier - probably the rcas running to your head unit.

[Edited on July 30, 2008 at 6:46 PM. Reason : seperate them shits.]

7/30/2008 6:46:01 PM

Would this be a possible mistake even from a very reputable installer? How would I separate them if that is it??

7/30/2008 8:25:49 PM

I'd go more for a ground loop problem... considering boats are typically fiber glass, unless the amps are directly beside the battery your going to be VERY susceptible to noise over the long ass ground run.

Your power cables make for a big antenna in a boat... get a bigger ground wire running to the battery is pretty much the only solution for this problem. It's not so much that they make an antenna as the I^2*R drop across the ground changing consistently... but if it's a constant hum it's a combination of the 2.

In a car you chassis ground everything and it's a local short run ground... can't do this in a boat.

[Edited on July 30, 2008 at 9:28 PM. Reason : not just an antenna, but your hearing the amps idle current from power supply degraded SNR]

7/30/2008 9:25:42 PM

The amp is right beside the battery.....are you saying the ground wire is connected to the battery?

7/31/2008 8:01:16 AM

Sounds like grounding issues to me too. Normally the ground will be connected straight to the battery on a boat. Look at the amp since it is right beside the battery and see if both power wires go to the battery.

Try disconnecting the RCAs from the amp first. If the hum is still there then the problem is in your amp or speaker wiring. If it goes away you need to check your RCA's and head unit.

Be sure to check for RCA's running right beside the power wires as someone previously mentioned.

7/31/2008 1:13:16 PM

if it's right beside the battery make sure that the ground is 8gauge or better run directly to the negative terminal as short as reasonable. it shouldn't be >18" ideally. check the ground of the Source also... b/c that matters just as much. Doesn't have to be as big of a wire, but it should be 14-16gauge or so... also the distribution block that the head unit is fed off of, make sure that ground wire to the battery looks well connected and of substantial size.

Better RCA's will have better shielding, may be worth looking into...

7/31/2008 6:24:13 PM