"New" 2015 242 Stereo Issues

[Nick Hughes]

I hate to post this, because I know there is plenty out about issues. But I had my stereo stolen in the spring, JLA M800/8 and M200/1, IB3 sub. Insurance covered it all, so I ordered a JLA XDM 800/8 and XDM600/1, IB6 sub. The thieves did just cut the speaker wires and unplug the RCAs, but things were still a mess. So I cleaned things up and have a massive hum in all speakers I cannot figure it out. Turning down the gain to near like 10% removes enough to make it not heard, but it's too low for what I've spent and come to expect. My setup is a 4g power and ground from the battery to the helm, 150amp breaker near the battery. And then 2 bus bars to feed both amps, then an 80 breaker and a 50 breaker for each amp. I've tried to eliminate variables and went battery straight to 1 amp, still there. Replaced RCAs, still there. Tried the front and rear RCAs pre-outs, still there.

I saw that potentially the head unit ground is under powered. I can splice in a 12g wire there to my new bus bar, but really not sure how that would help. Beyond all this, I'm curious what the right way to wire this from the pre-outs. Previously I had just the fronts to the 200/1, then out from there to the 800. Should I split the front and go to both amps, then the rear pre-out to the 800 and run in 4 channel?

Any help would be appreciated.

 

[Dave burke]

Not sure this is exactly on point but I had a similar issue with my 85 corvette. I had upgraded the HU, amp and speakers and had static which was super annoying. I tried a bunch of things like you and what finally worked was running a second ground wire from the HU chassis to the frame of the car. It's still working 3 years later.

 

[Nick Hughes]

Unfortunately no frame grounds in a boat, but I've had that issue in my older cars too. Would always increase with the accelerator depressed.

 

[Dave burke]

Right but do you have a distribution/grounding block for the amps? Maybe ground there? Or find a negative terminal/ground somewhere in the dash?

 

[Bluewater272]

Sounds like a grounding issue. When I upgraded the stereo on mine, I ended up with a similar issue and ended up having to take the ground from the radio out of the harness, and tying it into the ground for the amps. Took care of 99% of it.

 

[Nick Hughes]

I plan to cut the ground out of the harness and run a 12g to the bus bar I added. Still not sure how this would help as even though the bus has a dedicated 4g back to the house battery, the 2 batteries are grounded together, for what I assume is charging.

As for wiring out of the head unit, should I be using just the front or rear pre-amps or both?