Hi! I've got the exact same noise issue with my JP Premium. Do you find a solution?
I tried everything: swap the CPU board with another one, tried 3 sd cards, tried 4/8ohms, differents settings in Volume.... And there is still the same sizzling noise (it comes from the 3 speakers). I also heard the music with pinball browser and i don't hear the noise with the PC speakers. I contacted Stern about that and they will see with their engineers but are you guys found a solution?
teksavy
Thefuge