This 4-tube amplifier with 6W of output was found in an American manual from 1947. The sound quality is excellent.
The ZN414 integrated circuit consists of a complete radio from the 1980s. This single receiver...
This variable high pass filter covers the range from 23 Hz to 700 Hz with the components used. The...
This circuit is from documentation from Analog Devices from the 90s. The circuit uses operational...