This drum amplifier was found in an American documentation from 1947. It makes use of a mechanical vibrator to generate high voltage for the tubes.
This circuit uses a Darlington transistor and was found in a 1986 documentation. The circuit...
This circuit was found in Maxim's documentation from the 90's. The circuit provides 12 V x 120 mA....
This circuit was published in Radio Electronics magazine in August 1958 which taught how to...