Need a 4-pin to 3-pin adapter

milesfides · Post by **milesfides** » Fri Dec 31, 2004 9:42 pm

I want to use a Pabst 120mm 4412 fan as a cpu fan, but it appears it uses a 4 pin connector. Since I want to control the fan's speed, I'm thinking of somehow connecting it to the CPU fan input on the motherboard, which is 3-pin female.

anybody have any suggestions? I checked out some sites, which have a 3-pin to 4-pin adapter, but not the other way around

Tyrdium · Post by **Tyrdium** » Sat Jan 01, 2005 7:46 am

Like this?

Post by **Ralf Hutter** » Sat Jan 01, 2005 11:59 am

Check out SVC.com, they carry all that sort of stuff too.

JimK · Post by **JimK** » Sat Jan 01, 2005 3:03 pm

Also jab-tech.com for various plugs and wire setups.

milesfides · Post by **milesfides** » Sun Jan 02, 2005 4:09 pm

Thanks for the responses, but are those 4 to 3-pin adapters for power only?

Here's a response I got from d******'s forums:

"That type of product is not made for 1 reason; a motherboard fan connector's main role is not only to provide power to the fan, but to also monitor the RPMs of the fan, that is why there are 3 connectors on these connections, positive and negative terminals, and the third for RPMs.
But a fan that has a 4 pin molex connector only uses two of the pins (positive and negative terminals) and doesn't have a feature to report RPMs.
So in thought there is no reason to connect a 4 pin molex connector fan to the motherboard because it doesn't use the motherboard's main feature."

Is this true? So there would be no point in trying to connect a 4-pin connector (i.e., Papst 120mm 4412) to the motherboard's 3-pin connector, as the RPM monitoring would not work.

If this is the case, then is there any way to use the Papst 120mm 4 pin molex fan as a CPU fan, with some sort of speed control? Any suggestions? I know there has to be others like me out there who want to swap CPU fans!

greeef · Post by **greeef** » Sun Jan 02, 2005 4:59 pm

it's reccomended you dont attach a 120mm fan to a motherboard header - they tend to draw too much current.

wim · Post by **wim** » Sun Jan 02, 2005 5:36 pm

the thing Tyrdium linked is the wrong gender for what you want. d******'s forums response makes some sense (but overlooks what you want - the control from the fan header!) i would also point out that some molex-powered fans have rpm monitoring which you can keep, while the fan is powered directly from the psu - there is a 3 pin connecter for the board which has a ground, tacho, and blank.

of course, yes, there are other people here who have a setup like you want (voltage control on molex powered cpu fan). if 5V on the cpu fan is sufficient cooling, you can just do an easy wire swap trick to "control" the fan speed. but if you really want adjustable speed control there, your best plan is probably to get a Zalman fanmate 2 and change the plugs at each end (it comes with male and female 3 pin plugs and you will need to swap them for male and female molex plugs).

note you won't be able to automatically control fan speed using software in this setup! if that's what you really want, wire your own 3 pin plug in place of the molex (on the fan) and be wary of current limitations from the mobo as greeef has mentioned

ps: some people have bought commercial fan controllers to deal with problems like these, but i don't like them personally.

mb2 · Post by **mb2** » Sun Jan 02, 2005 6:00 pm

^ unless u are going to majorly undervolt it SPCR style

but still caution yea..

anyway, u can change the speed i'd imagine with that adapter thing, just it wont tell u how many RPM u are getting.
u can 5v or 7v using just the molex connector, but its not continuous or dynamic like through a 3pin connector can be.

milesfides · Post by **milesfides** » Sun Jan 02, 2005 6:15 pm

So software controlling is pretty much limited by endangering your motherboard. Undervolting isn't available on my Albatron px875p pro mobo, only voltage increasing.

It looks like the Zalman fanmate 2 (some reason why not fanmate 1?) would be the best option available, giving me the most flexibility, since I have no idea where I'll end up on the performance vs. noise ratio, and though I wouldn't have RPM monitoring, I do have CPU temperature available through MBM. Although it would be annoying to have to open up my computer case to increase fan speed whenever I want to do video editing or gaming.

One thing, how would I swap the 3 pin connectors on the fanmate with 4 pin molex connectors? Is there some article that shows you how to do it without having wiring skills?

Or would I have to get the 3 to 4 pin adaptors listed at above sites, and just deal with a nest of cables?

milesfides · Post by **milesfides** » Sun Jan 02, 2005 6:17 pm

wim wrote:
ps: some people have bought commercial fan controllers to deal with problems like these, but i don't like them personally.

isn't fanmate a commercial fan controller?

Tyrdium · Post by **Tyrdium** » Sun Jan 02, 2005 7:04 pm

wim wrote:the thing Tyrdium linked is the wrong gender for what you want.

Awuh? That's a Molex male, 3-pin female adaptor. It's exactly what you'd want for plugging a Molex fan into a 3-pin fan header on a motherboard.

wim · Post by **wim** » Sun Jan 02, 2005 11:10 pm

nah, it should be female both ends.. with molex, a device which draws power should be male and power is supplied by female.
molex fan eg. has male pins so it needs female socket. it would still work with those hermaphroditic fans but you are going backwards to convention - the reason they make them like that is so you still keep a spare psu plug while the fan is plugged in.

isn't fanmate a commercial fan controller?

well.. i suppose you could call it that! i was talking more about the multiple fan controllers which sit in a 5 1/4 bay and look ugly. the fanmate is just a little trinket in comparison

Tibors · Post by **Tibors** » Sun Jan 02, 2005 11:47 pm

So with a "hermaphroditic" fan it is actually a benefit it goes in the "wrong" way. I don't know what happens when you try to feed a 32% PWM 12V signal to a harddrive. But by being plugged in counter to convention your are prevented from accidentally finding it out.

milesfides · Post by **milesfides** » Mon Jan 03, 2005 4:13 am

greeef wrote:it's reccomended you dont attach a 120mm fan to a motherboard header - they tend to draw too much current.

How about the SPCR recommended Nexus 120mm fan: http://www.nexustek.nl/120mmcasefan.htm

It actually comes with a 3-pin motherboard connector...is that unsafe to use? Or maybe OK because it's a relatively weak fan, only 37 cfm.

I want to use a 120mm fan rated at 12VDC, 0.19A, 61 CFM, I hooked it up to my computer to test it, seemed Ok...is it a risk to use this long term? Wish Albatron had some info.

Tyrdium · Post by **Tyrdium** » Mon Jan 03, 2005 2:24 pm

Hrmmm... Ah, I see where the confusion is... Female headers on a motherboard, though? Aren't they usually male? This is really bizzare...