This is a diagram of a 1970s reel or tape recorder. It is an Italian Geloso recorder, quite popular at the time. The circuit is a reference for equipment recovery.
We found this circuit with an operational transconductance amplifier in the Motorola Linear...
Originally the circuit in the figure is indicated by National for the control of an electronic car injection...
This small two-transistor amplifier was found in the April 1994 issue of Electronics Now magazine. This...