Found in a February 1949 Radio Electronics magazine, this dual tube mixer has 4 inputs. Power must come from a 250V source.
This is a typical source of the time (1989) using the well-known regulator integrated circuit 723....
Found in American documentation from 1964, this circuit uses transistors from that time, which are not...
In the circuit of the figure, we have an application different from 4093. The astable...