Thanks. My father was a radio mechanic on Guam in WWII, which he parlayed into a career as a TV tech, then electronics tech for the USN. He decided to retire in the mid-70s because no one was using tubes any more.
I still have, of all things, an electric metronome; it was a Seth Thomas freebie, uses one triode, and still works today—but if the tube ever blew, I have no idea where I could find a new one.
And to bring it back to radio, my mother had a five-tube Emerson “portable” AM radio, meaning one could pick it up and move it from room to room, but it had to be plugged in. By the early 60s the heyday of radio dramas was over, and I never listened to them until we were in Japan and I heard them on FEN.
Your Dad had the now-mostly-lost knowledge, although there are still lots of people “doing” old radios as a hobby today. My husband Logitech is one of them. We have a bunch of old radios that he restores. Last week he found a very rare Musette radio from 1931 or so at an antique store.
He could advise you on where to get a new tube for your metronome. I’m pinging him to this comment.