We found this circuit in documentation from the 1980s. The component values are calculated using the formulas next to the diagram.
This high input impedance amplifier stage was found in a 1963 documentation. The transistor...
The function generator XR2206 is not very easy to obtain, but if you get one you can assemble this...
We found this circuit in the April 1982 Radio Electronics magazine. It contains a good power stage...