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Using A Fan Splitter With Molex Connector and A Fan Controller - Page 2

post #11 of 21
Quote:
Originally Posted by cgipson1 View Post

yes... but this cable may or may not even have power wires on the connector that would go to the mobo header.... it if did... it would be sending 12V into the mother board from the molex connector, unless there is a diode in the cable restricting flow to one way. So plugging that plug into your Recon, would not do anything. The tach cable is strictly for reading RPM.. not controlling it. And with no PWM signal coming from the Recon.... the fans would just run at full speed due to the 12v from the Molex connector.

Does that make sense?
Quote:
Originally Posted by pcoutu17 View Post

Ahhh, I see, I see. So, it's not the fact that the power is coming from a different source, but rather that the cables themselves may not have the required voltage regulating wires?

Which, looking at the cables more closely, it would seem that they only have pins 1, 2, and 4, which would be exactly the problem you're stating.

Pin 1 is GND
Pin 2 is 12V
Pin 3 is Tach signal... no rpm regulation, only reporting RPM
Pin 4 is PWM Signal.. which can regulate RPM on PWM compatible devices

http://cdn.overclock.net/c/c7/900x900px-LL-c7824258_3pinand4pindiagrams.jpeg
Edited by cgipson1 - 3/12/14 at 10:16am
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CPUMotherboardGraphicsGraphics
INtel 4770k ASUS maximus extreme VI  EVGA GTX 780Ti SC  EVGA GTX 780Ti SC 
GraphicsRAMHard DriveHard Drive
EVGA GTX 780Ti SC Kingston HyperX Beast 32 GB Kit (4x8 GB) 2400MH... Western Digital 2tb Enterprise Samsung 840 Pro SSD 256GB 
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post #12 of 21
There is no power to or from the motherboard in these Akasa AK-CBFA03-45 Flexa FP5 PWM Splitter Cables.
The splitter only has 2 leads in fan plug going to motherboard; PWM and RPM. 12v power and neutral leads are from PSU connector.

I've used these Akasa AK-CBFA03-45 Flexa FP5 PWM Splitter Cable in the past and don't like them. They have 5 leads connected to the PWM fan plug pins and 5 leads attached to the molex 12v and GRD connector pins.. and these tend to fatigue and break right at the pins. Open case to do something, leads move a little, one comes loose when cover goes back on and fan either runs full speed or not at all. Fix it and another one does the same. frown.gif

Use the Gelid PWM splitters or Swiftech hub
Edited by doyll - 3/12/14 at 10:21am
post #13 of 21
Thread Starter 
Quote:
Originally Posted by cgipson1 View Post


Pin 1 is GND
Pin 2 is 12V
Pin 3 is Tach signal... no rpm regulation, only reporting RPM
Pin 4 is PWM Signal.. which can regulate RPM on PWM compatible devices

http://cdn.overclock.net/c/c7/900x900px-LL-c7824258_3pinand4pindiagrams.jpeg

Ah, gotcha. Yup, looks like those cables only have the 3rd and 4th pins on the PWM connection (green and blue wires).

Oh well, so much for an easy fix. Looks like I'll just be better off eating the restocking fee and returning the PWM version for the 3pin. I have found a 4pin to 3pin adapter, but it would probably cost more to buy 15 of those than to just return the fans.

My only other option would be to go with something like THIS, and remove the guard so that the 4th pin can just hang off.

Edit: Just kidding, that one doesn't have the extra molex for power. I'll figure something out. Thanks a ton for the help guys. REP will be distributed shortly.
Edited by pcoutu17 - 3/12/14 at 10:31am
post #14 of 21
The fourth pin and PWM functionality doesn't matter if you're not using it. You're still out of a way to control the fans unless you get a stronger controller or multiple of them or lower-power fans. Even if your powered splitter cable has the nominal +12V connection going upstream, it's not going to work. Either you misremember something about the AP-29, I'm misunderstanding something, or it's wired up differently and has different electronics than most fans (isn't it only supposed to have molex power? where's the 3-pin coming from?)

If you're willing to send back the fans and if you're using voltage control, maybe just go with GT AP-15s for the low power consumption so you can run a bunch of them on each channel.
post #15 of 21
Thread Starter 
Quote:
Originally Posted by mikeaj View Post

The fourth pin and PWM functionality doesn't matter if you're not using it. You're still out of a way to control the fans unless you get a stronger controller or multiple of them or lower-power fans. Even if your powered splitter cable has the nominal +12V connection going upstream, it's not going to work. Either you misremember something about the AP-29, I'm misunderstanding something, or it's wired up differently and has different electronics than most fans (isn't it only supposed to have molex power? where's the 3-pin coming from?)

If you're willing to send back the fans and if you're using voltage control, maybe just go with GT AP-15s for the low power consumption so you can run a bunch of them on each channel.

Yeah, I was just looking at that. It would seem that there aren't any 3pin fan splitters that have a 4pin molex connector for extra power out there. I suppose my cheapest route may be to just get a second Recon and have half of the fans on one with and the other half on the 2nd.

Aha! I was misremembering something about the AP-29s. I forgot that either they, or my current fan controller, came with an adapter that allowed me to connect the 4pin molex to a 3pin header while still being voltage controlled. Something similar to this, http://www.frozencpu.com/products/16466/cab-982/ModRight_Black-Out_Series_3-Pin_Female_to_4-Pin_Male_-_12.html?gclid=CJbplKrKjb0CFSNp7AodrzsAng#blank.

Hypothetically speaking, would it be possible to get a custom wired splitter that has the extra 4 pin molex for the PSU, but then also has voltage regulation on the 3pin, or would that blow something up, since it would be directly regulating the voltage from the PSU?
Edited by pcoutu17 - 3/12/14 at 11:16am
post #16 of 21
Quote:
Originally Posted by pcoutu17 View Post

Hypothetically speaking, would it be possible to get a custom wired splitter that has the extra 4 pin molex for the PSU, but then also has voltage regulation on the 3pin, or would that blow something up, since it would be directly regulating the voltage from the PSU?

If it's just a bunch of wires, it should be as I explained earlier. It shouldn't blow anything up, but you wouldn't actually get voltage regulation. You'd just always straight-up have the +12V from the PSU.

If you put some electronics in there, you could easily do what you want, having voltage regulation and some or more of the power coming from the power supply.
post #17 of 21
Thread Starter 
Meh, I think I'm just gonna go with 2 of the Swiftech 8-Way PWM Splitter boxes and use software/bios for extra control.

Thanks again for the help y'all.
post #18 of 21
I have a mate here in UK who makes PWM to analog fan controlers
Quote:
Originally Posted by pcoutu17 View Post

Meh, I think I'm just gonna go with 2 of the Swiftech 8-Way PWM Splitter boxes and use software/bios for extra control.

Thanks again for the help y'all.
Keep in mind the PWM signal strength from motherboard fan header is not designed to supply lots of fans. My experience is 8-10 fans at most on Gigabyte motherboards.
The only PWM headers are CPU fan headers. Very few if any motherboard have PWM on other headers. Some ASUS say some other headers were and it has been proven to be false.
post #19 of 21
Thread Starter 
Quote:
Originally Posted by doyll View Post

I have a mate here in UK who makes PWM to analog fan controlers
Keep in mind the PWM signal strength from motherboard fan header is not designed to supply lots of fans. My experience is 8-10 fans at most on Gigabyte motherboards.
The only PWM headers are CPU fan headers. Very few if any motherboard have PWM on other headers. Some ASUS say some other headers were and it has been proven to be false.

Hm, that sounds pretty interesting. I'm sure I could find someone over here to rig something up if I tried, but I'm just aiming to keep it simple now.

Yeah, I've found that pretty much all of the motherboards that list system fan headers as PWM are lying. My board has a CPU and CPU-OPT header, would those share a signal or do you think they have seperate ones? I've seen a few threads where people have done it. I've even seen one where a guy got them working in series off of one header.
post #20 of 21
The number of fans PWM signal will support depends on motherboard signal strength and how sensitive / how strong a signal fan's PCB needs. Not all are the same.

I honestly know know if the CPU fan and CPU opt share the same motherboard signal power source or not. They do share the signal as fans hooked to both run the same speed.

I also don't know for sure if the Swiftech 8-way PWM hub has a PWM signal strength booster or not. My guess is it does not. You could contact Swiftech a note and ask. They have good customer support.
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