Hey guys, I have a wakeboat with a pretty nice setup, but recently I have started getting some really bad problems. When I have the stereo on while running the engine my 12" subs are making a popping sound, like a machine gun. There might also be some disturbance in the other speakers, but that is hard to tell since my subs are really loud. I have 3 batteries. 1 start, 2 stereo. If I run the engine and all the supplies and the head unit from the start battery and use the stereo batteries to only power my 3 amps there are no problems. As soon as I put my battery switch to "all" (thus connecting the stereo batteries to the starter and alternator) the problem comes back. I've been googleing the problem and first I figured it must be ignition noise from a loose or bad wire. But I've tried disconnecting one wire at a time from the coil with no difference (which I guess would exclude them from being the cause?). Then I disconnected the alternator, which immediately cured the problem. So my question is. How can the alternator cause this problem and what should I do to solve it? More info of the setup: I have a 1F cap installed on the power wire to the 3 amps. All the amps and speakers work perfectly with the engine off or the battery switch set on only the starter battery. The RCA cable to my sub-amp is no where near the power lines to the amps. The amps are powered directly from my 2 stereo batteries (with the cap in line) and grounded to the same 2 batteries. (No chassis since my hull is fiber glass). =) Thanks! //Mike