JJ E34L as suggested above are a well extended and well well balanaced EL34 type that works well in the Dynaco. They can be had for a very good price from Eurotubes.com I like the blue glass versions . I have been using them for years.
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.