Hi Astroimage, I am looking at the Paramount and not your amp, but I did notice that you didn't say anything about upgrading the output transformers. My experience on other SET amps made by a different mfr and PP amps, too, is that the biggest (and most expensive) sonic bang for the buck comes with new output transformers. Maybe you have already got the upgraded ones. If not, i'd discuss it with Doc and Paul and find out what the experiences of others are.
Coupling caps, boy, is that a minefield. I have two Danish Butter Cookie tins full of coupling caps I have tried and rejected (listening by ear) in various preamps, amps, and cd players, in almost all price ranges. The ones I ineviatbly do NOT return to the cookie tins are the new Audio Note copper foil ones, which are not cheap, but I suggest you not start at the top, but with the cheaper vintage ones, first It's easier to do the test with monoblocks because you can listen to different caps in different channels, but i generally try the Russian K-40s, Sprague silver colored vitamin Qs, first, and then work up. You might find out if anyone bypasses the coupling caps in this amp with any success (or try anyway). I found that worked well in a preamp with some small value Auricaps. By the way, I only know how to unsolder old parts and replace them with new parts that other people tell me about, so don't think I know what I am talking about. In fact, I am terrified of electric shocks, perhaps even phobic from some bad experiences.
Onward and upward.
