I have always found that 1940-1970 tubes are unequaled by newer tubes. Years ago I began buying good buys on a broad range of miniatures as well as output tubes. I have nearly 1000 tubes. They have been a great investment, even though now I use both a solid state amp and line stage. Tubes that one could buy for $8 in 1970 now sell for hundreds of dollars, some for more than $1000.
It is one of the costs of using tubes that you need to have a reserve stash.
It is one of the costs of using tubes that you need to have a reserve stash.