This active tone control circuit was found in American documentation from the 90's. The transistor can be general purpose or low noise with high gain.
This project is from a 1982 documentation, based on an astable multivibrator with two transistors. The...
Found in a 1967 US magazine this circuit generates positive and negative voltage pulses from a...
Rumble is a low frequency noise between 25 and 200 Hz that appears in old turntables, affecting...