[morzh]

John

I am not a life-long tube designer and so I do not keep the tubes' datasheets the way I keep semiconductor ones, and so I have to go by what what I find, and so fat what I find has the words "maximum" and "40 uF" next to each other.
I saw one sheet showing 40uF undet "typical" but then it did not show maimums.

So, if you produce a datasheet that says explicitly "maximum 50uF" I will agree with what you say.

Meantime, here's another one for the same tube I found.

   

And....speaking of "several decades of operating like this", we do not know how many time this tube was replaced.

PS. I am not saying the tube will immediately go up in smoke because of 50uF. Or even 100uF. It might last for years and, given today's "once in a blue moon" operation, might live forever. But to me this is a wrong way to do things. Even if it works.