This 1968 circuit makes use of MOSFETs of the time. The circuit can be mounted based on modern common FETs. Observe the high supply voltage.
We found this circuit in a Radio Electronics magazine from December 1969. The circuit uses a...
We found this circuit in a 1991 publication. It is intended for low-impedance microphones,...
This circuit can be used in the car to convert the 12 V from the battery in 6 or 9 V up to 2 A....