PWM to 3 pin fan connectors?@

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TheHogDog

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Any good recommendations on these?
My motherboard has three pin connectors and I was thinking of buying 2 noctua NF-F12s and they're PWM which are four pin connectors.

Most fan splitters are 3/4 pin connectors to 4 pin connector.

Is this one ok?
http://www.amazon.co.uk/Akasa-AK-CB002-PWM-splitter-smart/dp/B001J2YRUC/ref=sr_1_1?ie=UTF8&qid=1423167144&sr=8-1&keywords=PWM+splitter+to+3+pin

The "Connect to motherboard" is a 3 pin connector right?

Also, because you're using a molex (?) too, to plug in it into the PSU, would that not make the PWM fans run at full speed all the time?
 
Solution
drtweak
You can use a 4 pin on a 3 pin connector. They are usually fitted so that they ill fit on a 3 Pin properly as well. Only need something like what you said if you need extra power for fans if you run out of Motherboard Connectors.

Otherwise I would go with an Actual Fan Control unit and not some splittler.
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drtweak

drtweak

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You can use a 4 pin on a 3 pin connector. They are usually fitted so that they ill fit on a 3 Pin properly as well. Only need something like what you said if you need extra power for fans if you run out of Motherboard Connectors.

Otherwise I would go with an Actual Fan Control unit and not some splittler.
 
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hwc1954

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That splitter looks like all 4-pin PWM connectors. Just a plain 4-pin splitter, except that the fixed 12 V and Ground signals come from the power supply thru the Molex instead of from the MB 4-pin fan header. You would use this splitter to run multiple PWM fans from a single 4-pin header. If you plug a three pin fan into it, the fan will run at max speed (same as wiring it directly to a molex).

The Noctua PWM fans can be plugged into 4-pin headers or 3 pin headers. Plugged into 4pin headers, they operate in PWM mode -- constant 12V wire with the fan speed controlled by the PWM signal on the fourth wire.

If you connect them to a 3-pin header, they operate as conventional fans. They will run at full speed if the 12V signal is fixed. They will run at adjustable speed based on temp IF your MB has the option of variable voltage 3-pin headers.

I assume that your MB has at least one 4-pin PWM fan header for the CPU fan. The splitter you linked would allow you to connect your CPU fan and two Noctua PWM case fans to your CPU fan header. They will all increase/decrease speed in unison, based on CPU temps. That would be a good setup, IMO. I've got the same kind of splitter for four fans.

To be honest, you could just plug three PWM fans into the CPU fan header with a simple 4-pin header, but having the extra molex connection eliminates the small risk of drawing too much current from a fan header.

BTW, you can connect 3-pin fans to 4-pin headers or splitters. They match perfectly. The PWM wire is simply not connected. The other three pins are same on 3-pin stuff or 4-pin stuff (GROUND, +12V, tach/fan speed)
 
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TheHogDog

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I don't know how loud noctua NF-F12 fans are at full RPM.

The AF120 corsair was loud af when I connected it to the 3pin.

The rear fans I have a splitter so it's a 3pin/3pin into a 4pin which I then plugged into the motherboard and as it's converted to a four pin, both fans are controlled which are reasonably quiet enough.

You think it'd be worth buying a fan controller?
For the two noctua NF-F12s that I am going to use for the front and side of my case

Also if you can connect a 4 pin into a 3 pin connector then I don't need an ugly splitter like that, I could just buy the:
http://www.amazon.co.uk/Akasa-AK-CBFA04-15-Splitter-Cable-Fans/dp/B005FWXWPS/ref=sr_1_1?ie=UTF8&qid=1423170347&sr=8-1&keywords=fan+splitter

Are Noctua NF-F12 static pressure or air flow?
 
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hwc1954

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Yes. a simple splitter would work for connecting two or three Noctua fans to a single fan header. Or, if you want the type that supplies power from the power supply, you can get sleeved versions. Here's a three fan Akasa with a SATA power connector. They make it a molex, too. And five fan version of each:

http://www.amazon.co.uk/Akasa-AK-CBFA06-30-Flexa-Splitter-Cable/dp/B008FZBF7E

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I, personally, can't stand fans running at full speed. Even with Noctua fans, it's needlessly noisy for 90% of the time the computer is at low load. You can slow the fans to a fixed lower speed with the adaptors, but then they can't ramp up with the computer is under heavy load and you want full speed.

I have all my fans with variable control based on CPU temp. This can be achieved using all PWM fans connected to 4-pin headers. Or, it can also be achieved with 3-pin fans connected to variable voltage 3-pin headers. Or it can be achieved with a simple add-on that connects (with a splitter) to your 4-pin header and provides variable voltage control of 3-pin fans connected to it.

http://www.amazon.co.uk/Phanteks-PH-PWHUB_01-PWM-Fan-Hub/dp/B00M0R05WE

This thing is really tiny and can mounted with velcro. It allows variable speed control of 3-pin fans from the same PWM signal that controls your CPU fans.

The rear fans I have a splitter so it's a 3pin/3pin into a 4pin which I then plugged into the motherboard and as it's converted to a four pin, both fans are controlled which are reasonably quiet enough.
Click to expand...

If you have 3-pin fans connected to any MB fan header (3-pin or 4-pin) and the fans vary in speed with temp, then your motherboard is providing a variable +12volt signal on those headers. Some MB allow you to choose PWM, variable voltage, or fixed voltage for the fan headers. If you have enough variable fan headers for your needs, then simple splitters will take care of everything.

 
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TheHogDog

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I wish my motherboard had more 4 pins than only one..

Well just to make things easy... I'm just going to buy the two noctua NF-F12s and a fan controller.
http://www.amazon.co.uk/Channel-Pin-Connector-Blue-Controller/dp/B006Z8LB6S/ref=sr_1_2?ie=UTF8&qid=1423169358&sr=8-2&keywords=fan+controller#productDetails

Then for whatever reasons I may need to add another one or two fans, I can easily just install them into the fan controller.

Question:
That fan controller is the same installation as the optical drive installation right by the looks of it.
You can take one panel out of the front and install the fan controller through that?

Edit after reading the comment above, you sure?
Aren't I supposed to use a static pressure fan for the front fans?
 
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revenger681

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I connected my 3-pin fan into my 4-pin CPU slot. My motherboard states "PWM or DC Fan?" on it's CPU status, which would I select? I assume since it's a 3-pin I'd select DC. I've noticed the fan speeds up much faster when I change it to "PWM".
 
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Paperdoc

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If you connect a 3-pin fan to a true 4-pin port, it will always run full speed. To allow the mobo to control the 3-pin fan's speed in that situation, you need to tell the mobo to use Voltage Control Mode for that port (not PWM Mode). This choice is available on many mobo CPU_FAN ports these days, but not a common option for CHA_FAN ports.
 
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