This fuzz effect for guitars was found in an American 1980s documentation. The transistors may be the BC549 and should be battery powered for noise sensitivity. Diodes are commonly used.
Two inverters, of the 6 available in a Low-power Schottky 74LS04, are used in this anti-ring...
Found in Radio Electronics from the 90's, this circuit can be implemented with other operational...
Taken from a 1956 Raytheon transistor manual, this circuit uses varistors to obtain modulation of a signal...