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.

 

[Paperdoc]

There is a family of similar mobos with varied features, so getting a manual for THAT particular mobo us hard. BUT the manual I saw seems typical of the entire family as far as fans go. It shows four case vent fan headers labelled FAn1 to Fan4, plus one CPU cooler header labelled FANA. Its says each of those headers will feed to a 4-pin PWM fan, and the power limit from EACH is up to 2.5 A max current. The fans you talk about are spec'd at 0.54 A max per fan (higher than many because of high airflow and pressure specs). Still, with that high current limit per header you would have NO problem connecting two such fans to a single header using a simple SPLITTER like this

https://www.amazon.com/EKWB-EK-Cable-Y-Splitter-2-Fan-10cm/dp/B00K2F8PFA/ref=sr_1_2?crid=18F0EJRQF0MTR&dib=eyJ2IjoiMSJ9.rc8jIuBZBRMcmb63IEEZWZp8V6bT1e6XuDBkSEWj1LGwpTKt-MNa-kA0fpIDrvRyHwWswCh4tLJW2bm4l4EYlwRPV88jMDj1ZnC9dDxrNCXRc_NzT2BC_Z5qc0poEiiIl041cxvxzbjVnuYN1Mk1-Nq-IvqFLzN5-k_YVj5zn9MB4QpjbLCZzSp36tUje-jQxYyAGL_-BTcQ6xSANHhHffidBzdrz2KdFEu1eu_YY0Q.uHY4j1oYQj3bnD118fYcc-BPabmoZyLKI2lPBtJTF48&dib_tag=se&keywords=fan+splitter+4+pin&qid=1738694959&sprefix=fan+splitter,aps,125&sr=8-2&th=1

or something similar. NOTE that a Splitter is this simple - one input connector to plug into a mono header and two (or more) output connectors for fans. It has NO additional third cable to connect to the PSU directly.

Also note that such a device an return to the host header the speed signal of only ONE of its fans (the one linked has that output labelled with a tag). This does NOT impact ability of the header to control speed of ALL fans connected to it. But IF you really want to have every fan's speed displayed somewhere, you must connect each fan to its own header, then configure each header the same way so they all perform the same way.

Once you have your fans connected to headers in this manner, you can use the configuration details of the header(s) to set how their speeds are controlled automatically to keep up with changing heat load as your mobo's workload changes. That includes means of specifying low speeds for minimal temperature readings. You do not have to rig up custom fan modifications!

 

[dev_cyberpunk]

There is a family of similar mobos with varied features, so getting a manual for THAT particular mobo us hard.

It wasn't a big deal to get the manual and CD that came with the system. I have a Supermicro account and that is the real only way to download anything from them. Even though they don't make it easy to navigate in their customer portal. Because the buttons you would think you would need to click on do nothing, but the text links works.

Its just that with the default software and even in its ipmi web there isn't a way to customise the fan options. That is why I was looking for a quick and easy solution.
But I'm not 100% convinced that the back fans are going to be effective there since I am using hi flow fans and could channel the air through the back side of the motherboard.

But it would be nice to figure out how to set these fans individually if possible. I know Linux has an IPMI fan utility supermicro created for the motherboards, so later today I will try programming them from a usb boot of ubuntu.