Considering doing a certain style of 12 volt fan mod.

Taking 12 volts from the bottom side of the power plug in. But what I want to do is trim the power down to 9 volts before entering the fans.

Now, I could do the rheostat method. Nothing wrong about that.

But I am wondering about just putting a resistor inline on the positive wires going to the fan set.

What ohm of resistance would I need to knock 12 volt down to 9 ?

http://forums.xbox-scene.com/index.php?showtopic=637955
At top it says for 7v or 9volts, you can try that. If you really want it your current way, there's a bunch of ohm calculators you can use. from google.

My favorite method is to use 2n3904 transistors to lower voltage. They cost pennies and each one in series drops nearly 1V. So 3 in series from 12V source ~ 9V. Beats pulling the board out and loading mosfets. They can handle 1A fans without even getting warm.

http://www.youtube.com/watch?v=lC2OWCEzvaY


BTW for resistors: Watts = Amps X Volts. So for fat console fans looking to drop 3V; Watts = 09.A X 3V, you need a 2.7 watt resistor. You can probably buy 500 transistors for cheaper.

What about places where I can get a reliable 3 volts from ?

Don't want to take from Power Regs - seems like a bad idea.

If I put 12 volts on my positive line and 3 volts on my ground line, I'll get 9 volts on a fan set.

what about those unused junction ports ?

makes sense will keep this in mind

i just do the 12v fan mod and then ground to a 3v point

Are all the safe / usable 3v spots on the back side of Power regs ?

Doesn't seem practical to piggy back on those drain sides, but if its OK ... someone just say