6550 vs KT88 vs KT90

Many thanks to all on this thread and especially to Trelja who REALLY knows his tubes. This is what all the threads should be like. Mark me down as another happy KT88 owner. Anyone for driver tubes?

Trelja, just a note to you to mention that Jadis replied that the KT90s can be used in my old JA80s. I may get a set for when I run out of the NOS KT88s. Anyone with experience on how the new KT88s stack up against the older ones, sonically?

Rcprince, I am happy you put the question to Jadis. As stated before, they really seem to love the KT90. They go out of their way to recommend it in their products. I think Frank Garbie is a great guy, and seems to offer a lot of help. I have however, gotten information from him that conflicts with what Jadis advertises or says. Particularly in tube substitution. He wasn't aware my Orchestra Reference or some other Jadis amps accept tubes other than what they came with. He has given me excellent help when I have gone to him. I know horror stories abound, but I have nothing but positive things to say. I am sorry but I can not offer anything in regards to old KT88s, as I have no experience with them. I apologize. Enjoy the tubes, Krys!

I am trying to replace my tubes that originally was KT90's on my Jadis orchestra reference integrated amplifier. Beside that the KT90's are quite good I am curious of experiencing the KT88's specially from Valve Art, hoping to have little warmer sound with still good bass and extended treble of the 90's. If you have any experinence It would be great help. Thanks

I experimented with Ei KT90v.3 a while ago with my then owned VAC PA100/100. Biasing problems frustrated me enough to permanantly distrust them. Now, over a year with my replacement to the VAC amp, I too appreciate the mix n' match possibilities with my Audio Valve Challenger monoblocks. They were delivered with Sventlana EL34's then I ordered (12) JJ KT88's. Fat bass became solid bottom end, a musical, sweet midrange connects the bass to extended high frequency clarity. The versatility of the amps allowed me to mix (4) KT88's w/ (2) EL34's in each amp. I haven't tried 6550's due to my satisfaction at this stage and $$ for yet another dozen of tubes.