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.
Found in General Electric and 1967 documentation, this circuit automatically turns off the...
This amplifier stage without an output transformer was found in Radio Electronics magazine from...
Found in an Electronics World of 1968 this circuit can use current SCRs and the diodes are...