As far as I know EL34's are interchangable.It's mostly about experimenting with your particular amp and having some idea about what you are trying to improve. I have no experience with your amps at all, with stock tubes or otherwise. But, before I laid out big bucks for NOS tubes I'd do some experimenting with current product tubes. I found I liked the sound of Svet's which are also very dependable (no crashes in 4 sets - fairly long lived). In my amp these took the edge off some excessive brightness which was present with NOS Tesla's (E34L's). Also, don't over look the small tubes - these can have a bigger effect on you sound than the power tubes, and sometimes the right combo of power and small tubes will do more for you than either alone.
About Tubes.........
About tube rolling...
Are, for example, any EL34 tubes replaceable with any other EL34 tubes? In theory, I would expect a matched pair of circa 1963 EL34/6CA7 Mullard dual halo XF2 tubes, (at about $160 per pair)replacing stock Chinese or Russian tubes should significantly improve the sound quality of my amplifier. Is this thinking sound, or is it a simple trial and error method of finding the best tubes for rolling?
Somebody help me out here. Trying to learn, and having a hard time getting feedback in the forum.
Are, for example, any EL34 tubes replaceable with any other EL34 tubes? In theory, I would expect a matched pair of circa 1963 EL34/6CA7 Mullard dual halo XF2 tubes, (at about $160 per pair)replacing stock Chinese or Russian tubes should significantly improve the sound quality of my amplifier. Is this thinking sound, or is it a simple trial and error method of finding the best tubes for rolling?
Somebody help me out here. Trying to learn, and having a hard time getting feedback in the forum.