Thinking of fidelity in reproduction of classic music, no matter transistor, valves or tubes, there is a simple trick: go to a qualified theater and listen. That quality should be the goal.
For the modern bands, I think you have to sit on the grass and listen. That is the "standard" of quality you want to achieve I guess. BTW, in my life, I went to a stadium once to listen Bee Gees.
I love the concept of double blind test for, call it music, wine or olive oil. It seems not much loved by those in the blah, blah, blah...
Tell me about religions; we all need some from an infinite catalog.