Prefered 300B tubes for Canary Amplifiers

One reason amp manufacture utilize 300B's in PP configuration is to achieve more power. Since power is the objective, most 300B PP designs run the 300B at their maximum limit. That’s the general consensus, but as always, exceptions to the rule exist.

Can anyone estimate the longevity of a 300b in a "typical" SET?

The original WE specs predicted 40K hours as Brf said.Certainly that figure
will vary based on the brand and quality level of current tubes and how hard
that tube is stressed in a given amplifier. The Takatsuki is reportedly
constructed to a very high tolerance level (strict adherence to original 300b
specifications) with premium materials, only time will tell.When I got my
amp I asked the builder Israel Blume how long would the tubes last.He
replied that the amp is very conservative and easy on the 300b and they will
last for years(only 25 watt dissipation).Gary do you happen to know the
watt dissipation for your amplifier? The lower the number generally the less
stress on the tube.Maybe SET circuits are easier on the tubes, I really don't
know.
Regards,

Not sure how many watts are dissipated. I will try to find out. When I once asked Jarek (the amp designer) and Keiko (from Amtrans in Japan) the question of 300b longevity, they were non-commital. However, 40,000 hours!?! At this rate, my first pair is barely broken-in; my second pair will outlive me; and my plans to buy a third pair when I am in Japan in July are "stupid money" silly. LOL.