A very big trend for some time now is for the home DIYer to build his own switched mode power supply.  These power supplies when run from the mains electrical supply if not designed by a professional company which specialises in mains switching circuits can be downright deadly. Why not try a few circuits already built which can operate from a 12V battery supply and boosted to the rail voltage you require.

Another, possibly a bigger reason is if the DIYer has transformers which he or she has collected over time but the secondary voltages are too low to get the necessary supply rail voltages.

In comes the step up converter, more commonly known as the boost converter. (to drop the rail voltages we would use a step-down converter or buck converter.

Here are some exceptionally good value ready built circuits from a supplier in the East.