Reliability & Performance of Russian and other Recently Made

I would appreciate any information about the reliability and performance of recently made tubes from Russia and other sources.  For instance, I am interested in the 6E5C (6E5S) and the EL84/6BQ5.  I believe the 6E5C is only available from one source (Russia) but there are several current and recent sources of the EL84/6BQ5.  Is there a reliability or quality issue with the 6E5C?  Among the sources for a recently produced EL84/6BQ5, do any stand out as preferred and are there any to avoid?

Paul

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Please check Herr Knolls chart out.  He has done some extensive research in this area.

I hope that this helps.


Omer

http://www.radiomuseum.org/forumdata/upload/EL84%5FRussia%5Fsafe%2Epdf

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