Found in American documentation from the 90's, this JFET stage has an input impedance of 500 M ohms. Bipolar transistors are general purpose types and the FET supports an equivalent.
Published in Popular Electronics with the curious name of Obnoxious Noisemaker, this 1968 circuit...
This preamplifier circuit for turntable cartridges was found in the March 1994 issue of...
E) This circuit was found in documentation from the 1980s. The integrated circuit used is not very...