Hi I am new here and I am building a dual power supply with an ATX pre-regulator. I have already modified the ATX which is capable of 350 watts. I dismantled the ferrite transformer,output inductor, bridge rectifiers etc, and re- wound it to my needs to provide a dual 36 volts output. My second stage is to be an LM317T based voltage regulator with an TIP2955 transistor coupled with the 317 regulator. The ATX is to follow the main output voltage with 3 volts more in the input. I have bread boarded it and the switcher follows perfectly. This way it will give me 5 amps or more on every output voltage on each supply simultaneously. This way the dissipation is kept low on the pass transistor. My next stage is to include an LM301 opamp on each regulator to control the current individually on each supply, following the 317 regulator data sheet. My doubt is whether I should make 2 positive regulators which i can vary individually and hook up in series or parallel if i want to, or make one positive and one negative regulator. What are your suggestions about this project. Any advice will be considered. I will post my schematics as soon as i draw them.