Tube rolling eh. Which tube amp design that you have SET or Push Pull? And which power tubes are you using 6550, KT88, 6L6, KT90 or KT120? BTW, I was on a tube camp for a very long time before switching to SS design. Just a suggestion, the new manufactured tubes now a days especially the ones from Russia and the select few from China are just as good as the NOS ones, but, they are more prone to failure due to lack of quality control. It's best to find a dealership that you can trust and stick with them for warranty purposes as opposed to buying them from people that you don't know, which carries no warranty on the tubes.
In any case, both design topology do have their own strength and weaknesses, it just a matter of how they're being executed.
yes, use them with careful attention to operating points....
the materials used to make tubes a long time ago are simply no longer available today....
most of the factory workers, engineers are probably no longer around today
carrying their know-how to the grave...
that is the reason NOS are much sought after today, also why they are so expensive...
imho, Russian Tubes are tops especially those that were made for the Russian military...
Russian quality inspection i have witnessed first hand working in Russia six years,
inspectors sign their names in quality reports that they call "acts" or protocols,
and you can not pressure them into signing those reports if they did not do inspections,
they said they can end up in jail if something went wrong...
yesterday after listening to my newly built 6550 pp amp, i changed the amp with a 6C33 SET,
and i thought there was something wrong as the SPL were entirely different that i had to
bring out my power monitors to see if the 6C33 changed operating points, it did not...
in a nutshell, pp is about power and set is about euphonics sounds.....
