Originally Posted by theducks
The data on Hollow State Devices
is pretty stable.
a #80 hasn't changed much (Along with the newer 5U4, 5W4 )
Right you are there.
I'm a tad different here. I like collecting stuff like this. Sometimes, when just digging up some history on these items, checking older versions of the books can give me an idea as to when a specific tube may have been introduced.