That's brilliant. I just want to understand how capacitive coupling from AC lines or harmonics (can this occur?) behave using EMG with vacuum tubes, transistor and the modern op-amps version.Build an antique EMG with vacuum tubes like in the 1950s and 1960s.
Do vacuum tubes and transistors also have differential inputs and common mode rejection? We can just do a mental exploration of them if it's so difficult to acquire them.
I just want to know if there is any possibility any noises in the vacuum tubes and transistors can also somehow do some measurement like in the idea of chaos where order is hidden in the disorder. Chaos Theory.

