Yeahh,
I have seen it. But the generator was out of my mind. So the amp itself has no mains earth connection. And so the DUT was not mains earth referenced. But I have made a new one over the generator and so I have closed the circuit.
So, what kind of audio isolation transformer can I use? Or is there any kind of decoupler integrated in a BNC adapter?
So you can learn, read, watch and listen to any kind of electronic stuff, but you will never forger a mistake made by yourself.
I hope so.
Christian