Fan resistor guide?

[smiled]

Looking for an up to date fan resistor guide?

I'm trying to under volt my 120mm fan, cause I'm tired of hearing a vacuum when I'm on the computer.

I've already rewired the fan to 7 and 5 volt mod. But the 7 volt doesn't seem to safe and the 5 volt does little to nothing.

I'm not to familiar with electronics and need a guide to modding with resistors.

Will be using a 3pin 120mm fan rated at 2000RPM with a molex adapter if that helps.

Edit:
Just looked at resistor prices, WOW. Better off just getting a pack of pre built noise reduction cables.

 

[EarthDog]

or a fan controller... or hook it up to your motherboard headers and control it from there.

 

[Bobnova]

Resistors don't cost much IMO.
33ohms (gives ~7v for a 0.2a fan): http://www.digikey.com/product-detail/en/FMP100JR-52-33R/33WCT-ND/2058920

30 ohms, http://www.digikey.com/product-detail/en/RSF100JB-73-30R/30W-1-ND/18046

A calculator: http://www.blackfiveservices.co.uk/fanspeedcalc.php?Voltage=12&Current=0.2&Target=8

 

[smiled]

Thanks for the guide, but I got lazy and went ahead and got some noise reducing cables instead. Came in a five pack. Original plan was to use it on just one fan, but now I'll be using it on an additional pc and multiple fans.

or a fan controller... or hook it up to your motherboard headers and control it from there.

Don't have a fan controller and these fans are 3 pin, so no mobo fan control.

 

[manu2b]

... or hook it up to your motherboard headers and control it from there.

^This

 

[Bobnova]

Many mobos can do voltage control of fans. Not all, but many.

 

[manu2b]

^Yep, they usually run them from 40 to 100% (800 to 200rpm usually).

Just be aware of the max wattage, usually 25/30W per plug.

 

[smiled]

Ok I must have overlooked something or forgot to mention something.

This is a case fan and not the cpu fan. The case fan has 3 pins. The mobo needs 4 pin to control. Even with just the 3 pin fan I can't change the voltage on the fan, thus I went the modding path.

Unless I'm missing a step, I don't know how I would change the voltage on the case fan using the mobo header.

 

[manu2b]

What's your MoBo model?

 

[smiled]

What's your MoBo model?

Well this is what I'm working with.

Mobo: Gigabyte LGA 1155 DDR3 1600 Intel H77 HDMI SATA 6Gb/s USB 3.0 Mini ITX Motherboard GA-H77N-WIFI

The fan: Cooler Master 120mm R4 Computer Case Fan

 

[manu2b]

It should allow speed control through pin#2
http://www.manualowl.com/m/Gigabyte/GA-H77N-WIFI/Manual/318520?page=23

 

[smiled]

It should allow speed control through pin#2
http://www.manualowl.com/m/Gigabyte/GA-H77N-WIFI/Manual/318520?page=23

Yeah saw that when I first put the fan in.

This is all I could find in the bios.

1st System Fan Speed Control - Normal, Silent, Manual, Disabled
Slope PWM

Can't find any options to change PWM to voltage.