Jadis Defy 7 info-EL34s??

You should send an e - mail to Jadis.

In my queries to Jadis, they have only recommended two tubes to me(for several of their products). EL34/6CA7/E34L or KT90. They have told me the sound of 6550s is not as good, and their experience with KT88s have been horrific. Jadis used to be a proponent of 6550s before switching their allegiance to KT90s.

My feeling is that EL34s would be OK. Especially, if you like the sound(and that's what the picture showed). I presume the Defy 7 is autobias. As far as I know, the only Jadis amps which are not autobias are the Orchestra and Orchestra Reference, and they are perhaps the most difficult of tube amps to bias.

I'm not as familiar with the recent marks of this amp, but the French Jadis website says that it was originally designed for use with EL-34s, but the 6550s, even plain old GEs, sounded better. I would think you'd have to have someone change the internal bias if you want to do this, as the Defys weren't self-biasing like the JA 30s, 80s and 200s. Finally, in my view the Defy was always tubby and over-ripe in the bass, even with 6550s; I would expect the performance in that area with EL-34s to be even worse, although the midrange should be better. If you don't run it full-range, that might not be a problem.

As far as I am informed, EL34s are not the way to go. KT90s will work, as well as the types you've mentioned.