9v / 5v conversion for fans

Soldato
Joined
21 Jun 2004
Posts
2,790
Location
Berkshire
For ages i've used the good old cables with a resistor in the middle to convert 12v into 9v or 5v to make fans run slower and therefore quieter.

I'm building up a couple of rackmount systems and theyve got 4x 4CM fans which blow air through the case. These run at 10,000RPM, shift a ridiculous amount of air and are very noisy. As the airflow is overkill, I'm tempting to 9v or 5v it, however question of reliability comes to mind.

Is 4 fans going through a single one of those resistors going to be too much current/shorten the lifespan or it considerabley? I would have assumed that in general a resitor would last almost forever?

Cheers
 
Resistors have a rated wattage. Do the math (W=V*A) and then get one that's rated highly enough.

Good luck trying to build a quiet 1U machine that has sufficient airflow.
 
Not looking to build a quiet 1U, just want to slow down these fans a little as fans running at full wack 24x7 have a tendancy to dry out in a 1U. Not had this problem with other cases
 
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