first of all: noob disclaimer: sorry for the unprofessional sketch and my limited understanding of what I'm doing. I'll try my best to make myself understandable.
I'm trying to make a radio receiver that uses an external audio amplifier, but when I try to use the same power source (the AC-DC adapter), either the DC-DC buck converter or the FM receiver blows out because of over voltage or over current (smoke and sparks effect). Luckily those asian modules are cheap..
But if I use different AC-DC adapters for the FM receiver and the amplifier everything works. Why? How could I use a single power source for powering everything? I suspect the problem is some kind of ground loop etc, but I can't understand how to fix this.
In the below image the AND-gate is supposed to be a 3.5 mm audio jack and not an AND-gate.