Dad built an OM-2 before I was born. The two of us built my IO-12 in 1967, and I built a IO-105 in 1973. All three still work (I've replaced caps and a few tubes through the years).
It's tubes, not valves. Do you watch the valve or the tube? Do you say "electron valve", "vacuum valve" and "cathode ray valve"?
I rooted a sales-droid's Network General Sniffer while he was delivering his sales pitch to my Boss in about 1989.