A quality matched new old stock will for sure outlast a Russian tube by years
Andyat vintage tube services is by a country mile the most knowledgeable
he test tubes in over 8 catagories read his web pages I have bought from him since the 80s. The only down side sometimes a pain too contact Lio mailbox
on phone and email may take 30 days to answer. You choose how critical the grading by price the close the tube yo perfect the higher the cost
and his prices are fair. Nos tubes were all night and day better built in many ways
they inspected internal parts every 50- 100 pieces in many cases.
today by the 10000s the metal formulas used to be better ,the vacuum much better . Please remember there was no solid state ,these were critical in your tv,
or military if you see a W,wa, Jan more critically inspected ,in some PQ,SQ quality. For examples.40s - mid 70s end of an era.
today emmision labs aren’t very good for direct heated triode power tubes.
Andyat vintage tube services is by a country mile the most knowledgeable
he test tubes in over 8 catagories read his web pages I have bought from him since the 80s. The only down side sometimes a pain too contact Lio mailbox
on phone and email may take 30 days to answer. You choose how critical the grading by price the close the tube yo perfect the higher the cost
and his prices are fair. Nos tubes were all night and day better built in many ways
they inspected internal parts every 50- 100 pieces in many cases.
today by the 10000s the metal formulas used to be better ,the vacuum much better . Please remember there was no solid state ,these were critical in your tv,
or military if you see a W,wa, Jan more critically inspected ,in some PQ,SQ quality. For examples.40s - mid 70s end of an era.
today emmision labs aren’t very good for direct heated triode power tubes.