Manfred Kick wrote:
Slow and Easy going typically does the task already: 80mm: 5V supply 60mm: ~7,5V supply (they typically won't run below 6,2V) For the latter, you can use a 12V line, reduced by a 27 Ohm resistor (you may want to inject this into a separate Y-12/5V-cable :-). Attend to the power marking ("W" ) on your fan! The resistor has to be able to match it - don't take it too thin.
For the latter, you might be able to connect the fan wires across the +5v and +12v wires on your power cable. This gives you 7v to drive the fan, which should be enough to get it running at a low speed. This avoids the use of a dropping resistor, which will be yet another source of heat that has to be removed. This is a trick for helping to make a desk top computer quieter, which was developed by a group of people who might refer to themselves as "underclockers"; when silence is more important than screaming fast CPU speeds. eyc