Jadis Defy 7 MkIV w/ KT 90's tweeks

I originally owned Jadis Defy 7 MKI which used 6550 tubes and was happy with its performace for a few years. Last year I traded it in for MK4 which uses KT90 and found its performace much less satisfying than I had expected. The speed dropped condiderably, the images blurred, the bass became murky. After several tweakings with the dealer, we concluded it was the use of KT90 that degraded the sound. We finally ended up with installing G.E. 6550 tubes in place of KT90 ; that improved the sound tremendously. Also,further improvements were obtained by placing metal cones beneath the amp, which dramatically cleaned up the sound and sharpened the images. Try these methods, if you may,and see what degree of "Transparency" and "Aliveness" you can enhance for your music.

Andy, I compared my Defy 7 Mk I with GE 6550 Tubes and the KT 90. Speakers were Quads, cabling by nordost. The 6550's were nice, images sharp and stable, with the KT 90 as well, but they gave a tad more punch, speed and dynamics. That's the Mark I mind you. By the way, I've placed the Jadis on a slab of granite with three metal cones underneath the amp. Cheers

Sorry I've forgotten all about this thread. Sold the amp and preamp. Bought the JPS 2 and a pair of Nestorovic Amps. Love it. Will probably put another Jadis amp back in later on.