Diezel Einstein 50 W change el 34 vs 6l6 vs kt 77

[Mirek Satora]

Hi Peter,
I want to change the tubes El 34 for 6l6, event. kt 77
It's problem? What I have to do ? Now are inside el34...
Thank you, Mirek

 

[Peter Diezel]

Please see attached file.

 

[Mirek Satora]

Thank you,
And what 6l6? It's possible, or not?