You have to post an Ebay message to Dennis and hope for a response.
My fave tube by far for the Firebottle is the Gold Lion reissue KT77. MUCH better sounding than the JJs for some reason...in fact the JJs put me off 77s until I read enough about the Lions to give 'em a shot. Great sounding tube in that amp. I (mostly) got rid of a weird low level hum (only in my RELs when cranked up much further than when in use) when swapping out a 5U4g for the 274B rectifier. Raymonda's experience with the older model Klipsch Heresy is interesting, but very different from my experience with Heresy IIIs...improved in 2006 with titanium drivers and a new 12...these speaker are magnificent sounding, with zero fatigue smooth treble, amazing soundstaging, and I have 2 RELs to cover the 58hz bass rolloff. Simply a well sorted coherent speaker that really sings, and 99db efficiency makes my little Had amp work like its supposed to, with no tendency to run out of gas.