This circuit was found in a 80s American documentation. The zener diodes determine the points of action of each stage and the transistors can be general purpose types.
Scratch is the scratching noise that occurs on old, scratched discs and the rumble is the...
This circuit was found in the November 1974 Radio Electronics magazine. The voltage depends on the...
Found in a 90s Electronic Design, this circuit operates with Maxim components of the time. The...