Elecktor 10 Amp Switched Mode Power Supply
Although the diagram/schematic is for 17 volts, its quite easy using 
the LT1074 data sheet to reprogram the Power Supply for anything
between 2.5 - 40 volts. 
Its just 2 resistors that need to be recalculated and replaced.
My first version supplies an incredibly stable 24 volts for my CNC
machine with 3 x 2 amp stepper motors.