PWM 4 pin and splitters?

[chris-red]

Hi all, quick basic question. Can you sure a 4 pin PWM splitter which 2 different types of fan?

 

My reasoning for thinking it may be an issue is one of the pins is a rotation sense/ tacho right? I would have though the output of that would be confusing if the fans were running at different speeds?

[NorKris]

yes but make sure that the fans are wihin 100-200 RPM of eachother 

[PDifolco]

4 minutes ago, chris-red said:

Hi all, quick basic question. Can you sure a 4 pin PWM splitter which 2 different types of fan?

 

My reasoning for thinking it may be an issue is one of the pins is a rotation sense/ tacho right? I would have though the output of that would be confusing if the fans were running at different speeds?

As long as they are compatible they'll work, but the fan header will only give 1 speed report, you won't be able to set speed on each fan

[Alex Atkin UK]

8 minutes ago, chris-red said:

Hi all, quick basic question. Can you sure a 4 pin PWM splitter which 2 different types of fan?

 

My reasoning for thinking it may be an issue is one of the pins is a rotation sense/ tacho right? I would have though the output of that would be confusing if the fans were running at different speeds?

A correct splitter for this, such as what Noctua sell, only connects the tachometer pin to one of the fans.  I've used them extensively due to having several ITX builds and one of the motherboards had a flawed case fan header which didn't change fan speeds, so I connected the case fan alongside the CPU fan.

[Bismut]

6 minutes ago, Alex Atkin UK said:

A correct splitter for this, such as what Noctua sell, only connects the tachometer pin to one of the fans.

I've bought a five pack somewhere on the internet and it was the same way, all of them work great, even with entirely different fans.

[Alex Atkin UK]

1 minute ago, Bismut said:

I've bought a five pack somewhere on the internet and it was the same way, all of them work great, even with entirely different fans.

Yeah the Noctua are really expensive for what they are, but I wanted to be sure I got something with a sensible wire gauge as random stuff you never know if it can really handle the current rating you are potentially pulling.  I try to always avoid anything unbranded if its going inside my PC and has the potential for fire.

[Bismut]

3 minutes ago, Alex Atkin UK said:

I try to always avoid anything unbranded if its going inside my PC and has the potential for fire.

Why, do you not want to burn your house down or something? Lame! ^^

I do understand the rational though, but my fans only draw about 0.2A and I avoid daisy chaining them, so the risk is acceptable to me. I wouldn't want to get unbranded 12V PCIe extensions, that just sounds like a bad idea.

[chris-red]

2 hours ago, Alex Atkin UK said:

A correct splitter for this, such as what Noctua sell, only connects the tachometer pin to one of the fans.  I've used them extensively due to having several ITX builds and one of the motherboards had a flawed case fan header which didn't change fan speeds, so I connected the case fan alongside the CPU fan.

Great thanks, They are Noctua fans so that will be good, its a bit of a custom job involving 1x 120mm and 2x40mm fans all coming form a single header, I assumed there will be a noticeable difference between the fans speed.

[Bismut]

9 minutes ago, chris-red said:

I assumed there will be a noticeable difference between the fans speed

That could be, 5000/2=2500 and 2500/2=1250, if 50% duty cycle corresponds to 50% speed. There's those low noise adapters though, you could put one of those before the 40mms.