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4pin fan voltage control + splicing PWM signal questions

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March 6, 2011 8:47:50 PM

Ok so i have 2 questions:

1) Can you plug a 4pin PWM fan into a 3pin voltage controller and will it work. The extra pin is just a speed control for the fan turning on and off really quickly to regulate the speed (as far as i can see). If i disconnect (or just not plug in) this pin will this fan work as a normal fan and respond to voltage control?

2) To prevent overloading the CPU fan header could i instead splice some cables and take the PWM feed off the header and send it to other fans to control their speed. Would this signal be strong enough to control 6 or 7 fans? Voltage would be taken from psu through butchered molex connector. CPU fan would still be connected to header and only PWM signal would be spliced.

I need to get some new fans and the only ones available here i like are the Artic Cooling PWM ones that allow PST and the Thermalright ty-120. I've got space for 3 of each. I'd like to be able to control all of them with PWM off cpu header (without blowing it up) or leave the arctic cooling ones connected to the header using PST and control the thermalright ones with voltage (i cannot find an affordable PWM controller in my country)

NOTE: i will not be splicing the fans or their cables directly. I've got a bunch of extension wires lying around i can butcher then connect in series to the fans.

Any advice or insight welcome.

To sum up:
1) Will a PWM fan work with voltage control?
2) If you splice only the PWM signal off the CPU header is it powerful enough to control several fans?

P.S: very limited fan selection here so these ones are pretty much the only ones worth mentioning. No Yate Loons/scythes/etc...
March 6, 2011 10:26:39 PM

1) should work fine. As far as I know, 2) should work, as the PWM wire is a signal, but I could be wrong.
March 7, 2011 5:05:54 AM

Quote:
1) should work fine. As far as I know, 2) should work, as the PWM wire is a signal, but I could be wrong.


See that's the problem. I don't see any reason why it won't work but i can't find any info on someone dumb enough to try it. I think i shall have to volunteer for the role :) 

I think if i use voltage control i'll need to make sure i have the dial on full when booting so that the voltage is high enough to start the fans.

btw the way thanks for the quick reply.
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March 7, 2011 5:58:06 AM

Well, if you don't mind trying, I think that is the best way to find out.

If you have them above ~10 V they will probably start fine. (I've run 18 V motors off a 9 V battery!)
March 7, 2011 6:11:42 AM

I think i'm going to go for the ty-120s on voltage and the rest daisychained off the cpu header. I've found a 3channel voltage controller that should work. I'll post back in a couple of weeks so. The specs say the arctic cooling fans can run up to five fans so 4 should be within safety margins.

I'll also install a cutoff switch for the fans so when i'm not putting my system under load i can simply turn off all but one or two. Got a seperate 12v transformer that i can use to run the fans so no stress on psu with sudden voltage changes.

if for some reason that fails i'll just splice everything to cpu header's pwm signal and sell the fan controller.

Or i might splice off one of the fans in PST. They amplify the PWM signal so maybe that'll put out enough charge.

Anyway i'll post back if it works or fails so any other crazy person wondering the same thing can at least get an answer.
April 4, 2012 9:55:31 PM

just to add abit of info, the arctic cooling PST system uses there own fans and they say in there manuals that their fans are no more than 0.7A, and as you mentioned they also say only 5 of them at max--it seems they have an integrated system that doesn't welcome outside manufactures?? anyway, if you look at their manuals they also show how they set up the BIOS for their setup--good luck!
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