[TenTec] Centurion question

[jack]

bringing the tube up to voltage slowly also extends the life. Eimac (years 
ago) suggested the best application would be to put a variac in the high 
voltage power supply primary and run the voltage up manually. however Vern 
Campbell now a silent key, drove a 3-500Z with another 3-500Z until it gave 
up the ghost to see how long it would run. he said it lasted a week running 
as hot as he could manage. at times Eimac would receive a tube back from the 
user that had become gassy. they would run that tube hot for a day and then 
send it back to the consumer. i have no idea how the present tubes are 
manufactured however so cannot vouch for the new issue tubes.
jack ak7o