update for posterity: I just picked up the 50th edition (1973) from a used book store. It has a big chart of vacuum tube diagrams in the back. I didn't get an 8

update for posterity: I just picked up the 50th edition (1973) from a used book store. It has a big chart of vacuum tube diagrams in the back. I didn't get an 80s one since they didn't have it, but I'll still keep an eye out.