Stereo Noise Issues Revisited and a little wiring help from the Supra community?

Hello All!

I have a 2011 Launch 21v. Right after we purchased it, we made some upgrades to the system. In the boat, I'm using 3 pairs of WetSounds XS-650's and on the tower I'm using the WetSounds Double-Up speakers. I'm running two Kicker ZX650x4 amps to run it all. One amp is running the towers, while the other runs the speakers in the boat. Finally, I have a WS-420 EQ in the mix. Like a recent poster, I have the issue with "white" type noise coming through all speakers at all times. I've done a lot of car audio in the past, and had my share of issues with ground loops. However, in those cases, the noise usually only occurred when the engine was running (alternator whine, etc.) On the boat, I get the same hiss/white noise whether the boat is running or not.

From the previous post, it sounds like some have had success wiring the head unit directly to the battery and bypassing the Stereo accessory switch located by the steering wheel. If I did that, do I need to wire the WS-420 directly to the battery as well? The problem there is that I don't believe it has a dedicated on/off switch - it's just powered on when I flip the "stereo" switch.

Appreciate any feedback that you all may have.

Something probably has a bad ground. Does this have a fuse panel? Can you try pulling fuses until you find the offending accessory?