4 to 3 pin fan connector?

[gelat]

I have an aspire case with a rear fan w/led and a top blow hole with led. They are loud, and I want to slow them down. Problem is they do not connect to the motherboard, but to the PSU with a 4 pin molex connector. I have 2 mobo fan headers....

do I want to connect to the mobo, and where can I get 4 to 3 pin adaptors (all I see is 3 to 4).

Oh, AMD 4000 with a foxconn nforce4 ultra mobo

 

[Chopstick217]

Here u go: http://svc.com/4to3ad.html

 

[gelat]

Thanks - but I need clarification. One pin type allows monitoring, and the other speed control, but not both?

Which is best for what I want to do (reduce speed when it is just idling, and spin faster when needs to)

 

[Zepper]

If your fan has 3 wires, it is capable of speed monitoring, if only two wires then no speed monitoring. Some higher powered 3 wire fans have both types of connectors - one 3-pin to go to the speed monitor and the other 4-pin for power. Places like SVC, Jab-tech, etc. have adapters/extensions and some even have raw connectors to brew your own. The speed sensor (3rd) wire is to monitor speed. You put some kind of power control in the power wires to vary the speed. An ordinary rheostat (like the 25 Ohm 3 Watt unit that RS sells) will do fine as a speed control for most fans or you can build a variable voltage regulator circuit or buy them in a front panel fan controller like the sunbeam et al.

.bh.