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.
Today we have more compact solutions. This is from a Radio Electronics magazine from October 1990....
This filter was found in Texas Instruments documentation from the 1980s. The circuit uses a common...
16 commercial test circuit for tubes and transistors appeared in Radio Electronics magazine in...