The All American Five

[Nowhere-Man]

I agree they are a very clever design. I think old and simple engineering has a lot in its favour. What a good idea to simply drop voltage to supply heaters, lamp and then the main HT. They were reliable and practical. I imagine in those days the shops did routine repairs and valves were cheap to replace.
Today by chance someone gave me an old book on radio history with crystal sets as well. Lots of photos and even comic book advertisements. One advertisemment claimed a radio with loudspeaker output with no HT battery or valves. Just crystals.