This circuit can use almost any operating system and has a high input impedance. The power supply must be symmetrical. The circuit was obtained in documentation from the 1980s.
This circuit was found in a Ferranti documentation from 1969. The transistors are common types of...
This interesting passive circuit from an 80's publication measures the distortion of an audio...
This preamplifier circuit with a CK722 transistor appeared in Radio Electronics magazine in...