Originally Posted by gridlewak
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.
Old ARRL Handbooks might help
, but I don't know about the suffixes (5U4GB)
Nothing like the cheery glow of a pair of EL34's