Found in a 90’s Popular Electronics, this circuit uses a component that can be difficult to obtain today. It achieves a 10 dB noise reduction with the indicated components.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...