Stereo Interference

[crghou]

I installed a JL 6450 this weekend but am getting some feedback from the speakers. When I first installed it and had everything plumbed up and tested it everything sounded great. Then after getting the boat in the water and using the stereo for a bit i started to get humming from the speakers and even worse when the boat was running. I am using a good RCA cable to hook up the amp and it was used previously with the old amp. I am thinking it could be my power and ground cables but wanted to see before i bought new stuff. I was using some old wiring which was 6 or 8 AWG but JL says you need 4. Could that be the source of my problems?

Also does anyone have any experience with Y adapters? I need to Y into channel 1 and 2 for my amp and I only have 1 remaining output from my head unit. I tried a cable I had at home but it gave me some bad feedback as well. So for the time being I was only using 1 channel and only able to run 4 speakers.

thanks

[awake4air]

You could try removing the deck 12V constant power and ground out of the factory harness and go directly to the battery just like the amps. Try not to run the RCA cables next to power wires either.

[EarmarkMarine]

crghou,

The JL 6450 definitely requires a 4-gauge supply. But, I'm not sure that's the immediate source of your noise although if a ground connection is failing that could cause DC flow through the RCA shields.

Is the noise on all channels?

The first step in any diagnosis process is to verify that you have healthy voltage. This also means checking all grounds including those connecting batteries, engine block, helm buss and amplifier.

Verify that your HU power and ground reference the same battery or Perko Switch common post as the amplifier. Running a dedicated HU power and ground to or very near the amplifier supply terminals is always a good idea.

Substitute RCAs are easy to patch in and eliminate one by one.

If you're bridged, then double check which terminals you're using.

There are numerous other potential causes including a bad amplifier. So if the above quick checks don't reveal something I would strip it down to one RCA, speaker and operative channel, adding or substituting one external device at a time until the noise re-appears. And, you can totally isolate the amplifier from the boat and get it bench checked at the closest car stereo shop.

David
Earmark Marine

[crghou]

thanks i will give it a shot. I am going to start with getting some 4 gauge wires in there and trying to run my power cables a little farther away from the amp. I will also maybe try another set of RCA's.

I only noticed it on 2 of the speakers but the other speakers i had hooked up were the bow speakers and they were farther away from me. It was not really loud just annoying when your sitting. What is strange is i didn't notice it until after i had run it for a little while. Hopefully the correct wires will help out a lot.