Some of the early tube computers had some really interesting circuits. One that comes to mind is the use of "kirchoff adders," which are more-or-less analog adders with easy one-bit DACs and ADCs on the inputs/outputs. I can't remember if this ended up in the "final" IAS machine, but I'm pretty sure it was used in the MANIAC and is described in the "Second Interim Progress Report on the Physical Realization of an Electronic Computing Instrument": https://library.ias.edu/files/pdfs/ecp/secondinterimpro02ins....
