This circuit was found I a 1965 Radio Schack documentation. The transistors are from that time, admitting equivalents. The transformer has 500 ohm primary and secondary depending on the speaker.
This circuit was found in a European documentation from 1964. The circuit makes use of components of...
We found this circuit in the Linear Applications Handbook of the National Semiconductor of 1994....
This interesting circuit, found in a European publication from the 90s, has two control channels for...