Question Methods for slowing down two fans.

[dev_cyberpunk]

I have a Thermltake Tower 500 case and want to slow down the back two.

The two ways I can accomplish this is connecting the power in series and use the same PWM or use a flip flop on the pwm to half the speed by dividing the PWM TTL by two.

Also,should I lift the RPM lead or double the rpm signal?

Which way should I go? Or is there another way of doing that.

 

[Lutfij]

If your motherboard has support to manage each fan header, I'd get a PWM fan splitter/y-cable and then have those 2 fans off of one header, then set a custom profile in BIOS for that one header. This is assuming that the fans you're referring to are PWM.

Make and model of your motherboard? Make and model of your fans?

 

[Misgar]

When I have enough motherboard fan headers, I attach each fan to a separate header and control their speeds individually from the BIOS fan curve settings.

Alternatively, I'll use a a fan splitter if I don't have enough fan headers, or a fan hub.

On old systems where manual control is sufficient, I'll fit a front panel 3.5 or 5.25" controller, or use PCI brackets in spare slots. No need to dig out a CD4027B and a scrap of Vero board.

 

[faalin]

What motherboard do you have, most of the time you can set a fan profile in the BIOS, from the motherboard software, or a free program like speedfan.

If you want something hardware you could go with this LINK

 

[dev_cyberpunk]

Make and model of your motherboard? Make and model of your fans?

supermicro X10SLH-N6-ST031 motherboard
Iceberg Thermal IceGale Xtra 120mm

The fan options in IPMI only allow me to set the low rpm and profile to auto speed, heavy i/o speed profile and full on.

 

[dev_cyberpunk]

Another option I just thought of is using a series resistor on the 12V like the Noctua speed reducers.

Problem with integrating someone's speed controller is they might not handle the current draw. But of course I know how to build that seven different ways too and probably have the parts on hand to accomplish this.

Just trying to figure this out on my little workstation I want to build for myself with one of the newer style cases I never get to build in. Which is a challenge to get air cooling to work well in it.