I'm with Thatch here, some speakers just aren't made for tubes and if you need big watts - like over the 70 or so you can get out of a pair of 6550's – that’s probably SS territory.
I remember the showroom at the store where I bought a bunch of my gear back in the 80's, loaded with huge tube monoblocks that put out >100w, they all weighed hundreds of pounds and put out more heat than a contractor's salamander propane heater. Some of them where AR, CJ, VTL, Lumley, Jadis and all where trying to throw massive amounts of glass, iron and $$$ at getting tubes to work with speakers designed for solid-state. I remember asking to shop owner WTF, why do all this when you can just start with speakers that work with simple tube circuits in the first place? He just smiled and said “this is hi-end son; it’s more about money, magazine reviews and status than common sense”.
I STILL don’t understand why people choose this mismatched speaker route. It seems so simple, start with speakers that work with tubes if you want to use tubes and if you start with the real hi-efficiency stuff, all the better, you can dabble with low power SET. Sure, some may not like SET but don’t you think it would be nice to have that whole avenue of discovery open to you so you can decide for yourself?
