I need a power supply to give 12 to 15 volts @ 25A from a 48v rail. I have nearly always taken the advice that " you don't build switchers, you buy 'em. " But I can't seem to find anything suitable, the websites I've tried seem to be designed to teach you all about the company, the directors names, and the colour of the washroom walls before eventually admitting that they don't make what you want. Anyone out there able to help me find one?