Tube replacement for Dynaco ST 70


I just purchased a highly modified Dynaco St 70 and it came with EH EL 34 and I would lke to replace them since I feel they are a liitle thin and veiled on the upper midrange and lower treble regions where the voices are produced. Any suggestions on replaceing them with tubes that will open up and unveil the voices. I can uses 6L6 or KT 66.
cavy
I usually trust Upscale's recommendations. I've only heard their KT-66, but I've heard nothing but good things about the 77 as well.
Exocet 954
I have Will's mod also and just got the KT 66. Can u tell me what the basis setting should be on them
Thanks
Cavy,
Will Vincent recommends 1.40mV DC meter for KT66 and EL34 tubes. Just read your post today. Sorry for the late respond.