A friend of mine had a half gutted Buick radio from about 1938 and asked me to squeeze a circuit into it. So I went with a Princeton Champ 5f2a. I used half a dead reverb tank for the chassis. It’s pretty much a stock build and sounds surprisingly good in a closed back metal cabinet, pretty tight spacing in there. I used an old cast off transformer and B+ is about 50v high, so I may see how it sounds with Zeners. But for now it’s good!