single mosfet output stage ?

[AudioGeek]

ok... i know there has been some discussion about this before with various threads, but here goes again:

see:

http://www.marchandelec.com/ec616.htm

i am trying to figure out how they get 20db gain with a PS 42vdc with one output mosfet?

trying different combinations of drain and source resistors and cannot figure out how they got the values.

sooo....

i kinda want to do something similar... but use a 1:1 input tranny then the output stage.

how do i determine the exact resistor values... say using a irf140 as mosfet without randomly using simetrix or similar to find them?

thanks!!!

 

[flg]

They use a realativly hi gain FET 😀 A load R of 10 or 11 ohms or so and as small a source R as they can get away with 😀
The amp probably has a damping factor of 1 and THD about the same. Input Z can't be much higher either 😀
Might I suggest a ZEN Amp instead 😎