I built 2 of this insulated from each other to make a dual power supply, they can provide a maximum of 30V and 3A. Use 10 turns trimmers for a very fine current and voltage regulation. I used TIP147, BD139, TL082 and 1N4148...for the 35v i use a 150W boost converter and a 12v transformer.
If you use comparators instead of op amps, remove the two diodes in the outputs.
It would be cool to add another 2 differential op amps for the voltage and current feedback, because they are not very good.
