A-gon member Jfacker recently purchased some EI KT90s from me as well as some Gold Lion KT88s, found different strengths in the two types, and is using both sets depending on the music involved. If he doesn't post here you might want to contact him. From my experience in Jadis electronics, the Gold Lions ruled the midrange and soundstaging, the KT90s were probably tighter in the bass and much leaner overall. I far preferred the Gold Lions, but not sure how the modern KT88s stack up to them sonically, as I have not tried the new ones.
6550 to KT88
I switched out my EH6550's to JJ KT88's yesterday in my Rogue M120's, quite a difference from the get go...much better bass, sound stage is wide/deeper and overall I like the way they reproduce the music better... so now I'm wondering if the KT90's will be any better? Anyone go from the 88's to the 90's and stay with the 90's? Thanks for your comments.