In case anyone is interested in making a fan controller like mine, here's some info about it. I basically followed Uller's guide to make the circuit, but since I didn't have any capacitors, I left those out [it works fine anyways] The only real problem is the fact that the LM338K is only available in the metal package, not the plastic, smaller one that the LM317 is. At least I couldn't find the LM338 in that package.
Also, you would need to actively cool the heatsink for this circuit. I left my 26W Rotron on that circuit, running at 7V, for about 2 hours, and the heatsink was burning hot. It's not the biggest HS, just half a cheap Athlon OEM one. Seems odd to have to add more fans to your case when you end goal is to reduce the noise of your existing fans =]
Here's some links to things:
Uller's Guide:
http://casemods.pointofnoreturn.org/vregtut/
Info on LM338K:
http://www.national.com/pf/LM/LM338.html
Link to buy an LM338K:
http://sales.goldmine-elec.com/prodinfo.asp?prodid=8586
Hope somebody finds this useful =]
BO(V)BZ