but to tell the truth, I really dislike the sound of the system right after I use it. I just do it for maintenance purposes.
That's why I mentioned the old tubes with steel pins cleaned to "gleaming". A couple of the tubes I've gotten like that were absolutely shrill and unlistenable - very out of character from what I had come to expect of an RCA. One set was RCA 12AY7 black plates, another was RCA 12AX7 gray plates.