We found this circuit in the March 1984 issue of Radio Electronics magazine. The module used is a common type at the time. The other integrated circuits are common types.
The purpose of this circuit is to eliminate RF picked up by a turntable. The circuit is from a...
This circuit synchronized by the power grid can be used as a shield. We found it in an 80's...
This is a very simple version in which we simply fit the jacks, plugs with red and green LEDs,...