This TTL shield with high level logic is from the LM111's own 80's manual. The integrated circuit is no longer easily found, but the circuit can be adapted to use modern equivalent operational amplifiers.
This is the traditional configuration of a 6 or 12 V source with 7806 or 7812 integrated circuits, for a...
This fader or guitar fading circuit was found in an American documentation from the 1980s. The...
Found in documentation from the 1960s, this power supply employs germanium diodes from the time....