Here follows a simple and really economical 10A variable power supply (1.2-30V). An LM317 have been used to drive 3 npn TIP41C transistors (or, better, three 2N3055). Nothing to say about the project, it is really simple. The main supply must be connected to a rectified source (transformer + 25-30A bridge rectifier).
For Q1,2 and 3 can be used any power TO220 transistor (TIP132C,TIP41C etc) or three external 2N3055 transistors
The three 0.1ohm resistors are 5W resistors. The Tip41C supports upto 6A with a collector dissipation of 65W max; a cooler is a must. If an higher power is needed they can be replaced by three external 2N3055 (115W) or other NPN power transistors. Pad1 and Pad, if an amperometer is not used, must be short-circuited.
Schematics and board can be, as usual, downloaded from the repository.