diyAudio - Is this stable??

hey
This is not an amplifier.
It is a model, a topology that could be used for designing an amplifier.

It will work.

How good,
it depends on how big the resistors are
and what are all the other components

These resistors provide local feedback around transistors
and limit the total gain
If resistors are given higher values, it will limit DC gain (and AC gain)
and make the output more controlled

The amp total gain is set mainly by RD and RS
and formula is roughly a bit less than: 2 x (RD / RS)
as both halves help with the gain

RE will set and help to control the idle current in the output

This amp shouldn't be too sensitive to Power Supply = reasonably good PSRR
But of course,
the voltage supply would be limited to what input JFET can take.

It is simple.
There is no global feedback.
At lower voltage output it can be interesting and have not too much distortion.

This model as it is, is for a preamplifier.
Possibly with proper transistor and component choice could be a nice headphone amplifier.

lineup :)