Negative Feedback Amplifiers (Fuzz Face) Analysis @ Wikipedia

[mac]

http://en.wikipedia.org/wiki/Negative_feedback_amplifier#Two-port_analysis_of_feedback

Fig 3 looks familiar

mac

[PRR]

> Fig 3 looks familiar

Used in millions of magnetic phono input stages, microphone amps, and even a popular video amp from 1971 (somewhat elaborated). IIRC(?), analyzed in GE's 1964 Transistor Handbook. Probably the first WIDELY-used 2-transistor compound.

In many-many audio circuits, R2 is approximately bypassed with a cap. To the extent this is true (sometimes not much), the g parameters are simpler.