You converted yours to use the 6SN7's?! Nice! Much better than 12AU7's?
I've got a RCA long black plate 5963, Tung-Sol5998 with HD650. Source is a Squeezebox Duet with a Stello DA-220.
Just bought another Crack kit. Going to use it for testing and then, maybe, what I think I'll call a BAC (Big A$$ Crack).