All: I think this thread has not been posted for some time, but I stumbled across it while researching, with an intent to purchase the WA6SE. Reason for posting: I once owned an Art Audio PX25 amplifier (single ended, using the PX25 tube for 6 whopping glorious watts). It shipped with a pair of Sophia 274B tubes as rectifiers. However, at their suggestion, I had them ship a pair of CV378 rectifier tubes, and WOW, the improvement was fantastic, and very unexpected. I would not have dreamed that a pair of rectifier tubes could make such an improvement to sound.
So I asked Jack if the WA6 SE would accept the CV378 rectifier tube as a replacement. He said yes, it would. So maybe some of you with either version of the WA6 might want to try the CV378 and report back?