Interesting: paper on distortion of FET, BJT and triodes and feedback

[Steben]

The fetzer trick is explained in detail: a (j)FET with source feedback shows a distortion profile / fourier analysis similar to a triode.
The increase of noise level is mentioned.

https://www.its.caltech.edu/~musiclab/feedback-paper-acrobat.pdf

Makes me think the Fetzer might be improved if NOT used as an input stage but after a low noise high input impedance moderate gain stage, where a classic non inverting opamp stage is ideal I think to enhance the signal to noise ratio of the feedback fet stage.
Or why not use a BJT looking at the profiles....

Or am I wrong here?

[Kipper4]

Thanks for sharing. Book marked and saved to file.
Cheers