In my amp I've been using JJ KT77's and recently switched over to Winged C EL34's. The KT77's have a larger soundstage, better bass, slightly better highs, and more neutral reponse. To me, the JJ KT77 sounds closer to KT88's than any EL34. In my system prefer the Winged C EL34s.... better midrange, bloomier soundstage, more natural sounding, and more musical. With the KT77's I'd constantly catch myself listening for certain audiophile queues constantly changing songs. With the EL34's I find myself just listening to the music more rather than analyzing to my system. So with my setup and my taste, Winged C EL34's are a better match.