I finally traced my noise-burst issues that appear randomly when playing passersby and make it unusable for me.
It seems to be connected to that funky mini usb power jack of the raspi 3b, when the burst (a bit like ring mod noise) happens it repeats a few times with notes played and disapears.
When that happens, the red light of the pi goes off and the yellow act flashes shortly a few times, when the noise disapears the red light goes back on.
It seems like when i press the mini usb real hard into the jack, it doesnt happen, yet nothing seems loose or wobbly.
Any idea of a permanent fix besides glue? And does this sound familiar to anybody?