This circuit uses a General Electric coupler from the time of the publication in the 1980s. Equivalent SCR can be used.
This circuit was found in an American documentation from 1970. We can increase the number of...
This sound effect for guitars uses a 555 to modulate the signal from an instgrument pick-up. The...
With NAB equalization we found this circuit in an English documentation from 1967. The transistors used...