Wet sounds speaker hum

[Wetjet57]

I installed a pair of rev 10 wetsound speakers with a wetsounds amp. When the boat is not running they sound great, when the boat is running you can hear a humming noise. Doing a little research I thought it was maybe a ground loop so I tried grounding the stereo head to the amp, that didn't work. Next I tried unplugging the rca's to the amp and the hum went away. Plugged my phone directly into the amp and the speakers sound great with no hum. Plug the rca's back in and the him comes right back. Prior to changing the ground on the head the hum would get very loud when I turn the blower on but since I moved the ground that has went away. Any ideas on what the cause could be??

 

[thorsome]

Mine does the same. I have their HT-4 amp. What amp are you using?

 

[Wetjet57]

Same amp. Even tried a noise isolated between stereo head and amp.

 

[PaulyB]

I thought I read somewhere recently where somebody grounded their RCA cable and it went away, but Im not 100 percent on what they did exactly.

 

[Wetjet57]

There was a ground on the isolator I tried but the directions said it wasn't required. Maybe I'll try that. The hard part is i can't problem shoot unless I'm on the water because it's perfect when the boat is not running on land.

 

[CraigAR]

@Wetjet57 are your rca cables ran next to your power and ground wires? You will get feedback if they are. Power and ground wires straight to the battery. Remote wire from amp to head unit and rca' s from amp to head unit and you shouldn't have any problems.

 

[Wetjet57]

They are somewhat close to he power wire that runs to a second amp that I have powering my speakers inside the boat. That was my next check, pulling the rca's and running them a different route.

 

[CraigAR]

They are somewhat close to he power wire that runs to a second amp that I have powering my speakers inside the boat. That was my next check, pulling the rca's and running them a different route.

That's most likely the cause, like I said if you have the power and ground wires directly to your battery make sure the rca cables don't take the same path. Post your results after moving the rca' s. If that doesn't work, ill have to know exactly how your amps are wired.

 

[Wetjet57]

Thanks @CraigAR. I'll rerun that this weekend and get on the water to test it if we get any decent weather

 

[David Analog]

First, you should have zero noise that is created by the boat electronics, such as stators, blowers, and the like. Here are a few tips.
The amplifiers signal grounds don't reference true ground. Although the HU RCA ground shields do reference ground. This is the simple scheme that avoids ground loops in the signal path. The only time you 'add' a ground wire to an RCA shield is if the HU RCA grounds have been damaged due to incorrect installation procedures and no longer reference continuity to the HU chassis.
You do not have to go to the trouble of re-routing the RCA cables in order to diagnose the potential for radiated noise. You only need to 1) plug in the RCA cables to the amplifier, 2) unplug the RCAs from the HU, 3) short the HU end of the RCAs (left to right), and 4) leave the RCAs in the original path. Either you still have noise or you don't. If you don't, it's not the RCA cables or the cable path. It's a ground loop. If you have noise then re-route the cables and if necessary replace the RCA cables (especially if you have twisted pair).
Ground loop isolators place tiny coupling transformers in the signal path. They degrade the sound quality. This is just a cheap band aid that keeps the real problems intact. Not a good choice.
JL Audio amplifiers feature differential inputs that by design help reduce radiated noise.
You should be dependent on your equipment dealer to provide the correct installation procedures so you don't have noise out of the gate, and then if you do have noise, to provide you with the correct trouble-shooting procedures. That the dealer's responsibility. If your dealer isn't giving you this technical support, then you have got the wrong dealer.

 

[Wetjet57]

Thanks for the detailed response @David Analog. Just to make sure what you mean by "short" the rca cables. Simply unplug both, then only plug the left into the right? Leave the other unplugged?

I bought everything from wet sounds directly and sonic electronixs online and both have been helpful over the phone but still haven't gotten to the bottom of the issue. Installing everything myself was the first time I've done anything like this so I could have made a minor mistake that's causing it. First being wear I mounted the amp. I mounted it near the rear of the boat so I didn't have to run the power as far, doing it again I would mount under the console so my rca's are short. Could that also be a potential cause?

 

[thorsome]

wetjet57, you remembered correctly and I'm the one who grounded the amp to itself with some success. I've been told that the ht series amps were inherently noisy. Perhaps that's why it was discontinued.
Regardless, I have 3 amps made by 3 different brands (all are side by side) and the wetsounds is the only one that makes noise. What's weird is that the noise continues for a brief moment after the engines are turned off.
One day, I'll probably swap it out for something of better quality, but I've reached the limit of how much I'm willing to spend for the time being.