Hi Kleinstein, :-)
The Sziklai Darlinton is not the problem, it is stable, but you have to make him stable.
Just connecting two transistor together is asking problems...
Just a small emittor resistor on the driver and direct on the base of de driver a small resistor, BINGO and its stable
Even with the fast Audio transitors!
Q3 can be a BD139, low cost en good.
I find al this poles a little to much...
Ik like the simple design of the Harrison/HP power supply's.
I have improved the design with good results, basically it's still the Harrison Design,
but with piek current limitor,
extreme low noise reference (output noise under full load < 5uV (22Khz bandwith)
no power of / power off abberations.
Just some "tender loving care" for de Harrison design.
But i can see dat de design of
prasimix has potential, and he is learning a lot :-)
I have not used any spice for "my" design, but real measurements, yes it cost a lot of time, but now I know for sure what the performance is of that power supply, real data.
Like you told, it is difficult to "spice" wiring, a lot of people do not know, how to wire a Power Supply for Low Noise, under heave load changes.
The current wiring is best to twist and the sense wires at an angle of 90 degrees to the controle circuit.
Kind regarts,
Blackdog