Prefered 300B tubes for Canary Amplifiers

Based on the WE300B spec sheet, they should last for 40,000 hours. Remember, the 300B tube was developed to amplify telephone signals back in the late 30's.

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.

I think the WE spec was "up to" 40K. Like Charles mentioned, it depends on how hard they are ran (voltage and current).

I have 2 300b SET's, that run the tubes in the low 20's watt/dis. I have a PP 300b that actually runs about the same maybe a little less.

Gary,
I know, 40K hours is hard to grasp.As Brf pointed out however this tube was designed for very long and trouble free use fot telephone line service. This was meant to be from the outset an ultra low maintenance service tube. What is critical is how meticulously the various current 300b tubes are made.Suppositly this is a design objective by the Japanese engineers assigned to the Takatsuki project.The tubes are too recently developed to know yet their longevity. I can only attest to superior sound at this stage.
Regards,