Many of us building simpits will require various different voltages to be available in the pit to make various components work. Buying a dedicated power supply, such as an experimenter's benchtop unit is one option... but how many of you knew that an old computer power supply can be modified to that purpose? Modified computer power supplies will easily provide that +3V, +5V and +12V voltages that are commonly needed in simpits.
I found a good write ups of the conversion process here: http://web2.murraystate.edu/andy.batts/ ... SUPPLY.HTM
http://www.tc.umn.edu/~beck0778/powersupply.html
Make sure you read the safety warnings and do not attempt the conversion unless you are confident in your ability to carry it out safely. The second link shows the use of a fuse in the supply, this is certainly a good idea!