I don`t have too much free time, and those "experiments" and listening tests are really time-consuming. Right now I`m switching back and forth between 6J5GT and 6C45Pi tubes. I listen to the strenghts and flaws...CCS (Mu and anode outs), resistive load, caps... The Ideal is hard to achieve. New report in a few days... P.S. about music - I just realized that I`m listening to the lo-fi stuff mostly... don`t have excellent recordings at all.