how to volt mod a 3 pin fan?

[IlllI]

i have no idea where to ask this question. i figure this is as good a place as any

i've been able to volt mod 4 pin fans in the past (basically switching two wires with each other) but i'm wondering if i can do the same with a 3 pin fan? i've looked online.. inconclusive. basically all i've found was how to volt mod using a resistor(?).. which i'd rather not do.

if someone can steer me in the right direction i'd appreciate it

 

[Fullmetal Chocobo]

I know of one way to volt mod the fan without using a resistor, so I'm not sure if this is what you are referring to. Basically you use the 12v & 5v source from the incoming 4-wire molex connector instead of 12 & ground. The voltage difference results in 7v going to the fan.

EDIT: I have read different things on if this could cause damage to your PSU. So I would post in PSUs about that if you are considering the mod.

 

[mechBgon]

How about volt-modding a 4-pin-to-3-pin adapter, then run the 3-pin fan from the modified adapter? That's what I'd do.

 

[corkyg]

Initially, two-wire fans with simple on-or-off control were used for cooling. One of the immediate improvements was the addition of a third wire to provide a tachometer or sense signal. In many systems the input is used merely to monitor the fan's rotation for safety purposes.

If you don't need to monitor the fan's speed, then you can just ignore the 3rd wire.

 

[JackMDS]

Hmm....

What is Volt Mode?

How can you modify a Volt??? :shocked:

 

[mechBgon]

Originally posted by: JackMDS
Hmm....

What is Volt Mode?

How can you modify a Volt??? :shocked:

It means that the fan is given a reduced voltage to slow it down (and quiet it down). It's usually done by grounding the fan to the power supply's +5V line instead of to a ground wire, which reduces the effective voltage to (12 - 5) = 7 volts. Grounding to +5V can be done by modifying a typical 4-pin-to-3-pin Molex-style adapter, hence "volt modding".

 

[JackMDS]

Originally posted by: mechBgon

Originally posted by: JackMDS
Hmm....

What is Volt Mode?

How can you modify a Volt??? :shocked:

It means that the fan is given a reduced voltage to slow it down (and quiet it down). It's usually done by grounding the fan to the power supply's +5V line instead of to a ground wire, which reduces the effective voltage to (12 - 5) = 7 volts. Grounding to +5V can be done by modifying a typical 4-pin-to-3-pin Molex-style adapter, hence "volt modding".

LOL. Thanks mechBgon.

I am familiar with the issue as you described it. I was not aware that it is referred to as a "Volt Mode".

 

[IlllI]

Originally posted by: mechBgon
How about volt-modding a 4-pin-to-3-pin adapter, then run the 3-pin fan from the modified adapter? That's what I'd do.

i was considering doing that.. however i still wanted to use the 3 pin connection on the mobo if possible. i'm using a shuttle sff and modded a 120mm fan onto the back, so i dont have too many 4 pin connectors..actually i think i only have 3. 1 for hd, 1 for optical and 1 for video card.


edit: i'm not sure if it has a rpm sensor or not.. i'm thinking no b/c it was pretty cheap. but i guess i can take a look in the bios and see if theres a way to control the speed. at the default speed its too loud, however doing a 7 volt mod makes it whisper quiet

 

[JackMDS]

Get a Y cable for a dollar or two.

 

[Zap]

Originally posted by: clandren
i still wanted to use the 3 pin connection on the mobo if possible

The only way to do this with a motherboard 3 pin connection is to use a resistor.

Here's one for $4 shipped but only drops from 12v to 10v, not much. Here's a Zalman for $2.75 plus shipping that drops to 7v.

You can do it yourself too, if you know which resistor value to use and can do a nice job of soldering/heatshrinking.

 

[IlllI]

the only problem with doing it myself is.. i dont own a soldering iron, nor do i know how to solder but that zalman one looks exactly like what i want.

before i read your post, i found this guide online http://www.overclockers.com/tips766/

i think i've got one of those little doodads lying around somewhere. it would mean more clutter however.

 

[LittleNemoNES]

resurrecting this thread to ask:

Will the zalman (http://www.quietpcusa.com/Zalm...tor-Cable-P102C0.aspx) push my 3kRPM Ultra Kaze fans to below 1800RPM?
Thanks!

 

[LittleNemoNES]

bump

 

[0roo0roo]

zalman fanmate
or another cheap knobbed fanbus.
less trouble, and infinitely variable speed at a touch.
its much better than volt modding. esp the 12-5 one which supposedly puts a burden on the psu..

 

[MatthewF01]

I just came up with a way to voltmod in a manner that no guides have discussed.

All the guides ive seen, such as this one:
http://www.techpowerup.com/printarticle.php?id=137

involve the use of both a molex to molex cable (male to female), AND a 3-to4-pin adapter.
I couldnt find a straight molex to molex cable, and all I had was the 3-pin to 4-pin molex adapter that came with the fan.

The 3 pin connector is actually just two wires, a red wire connected to the yellow pin of the male end of molex and a black wire connected to the first black (ground) of the male side of the molex.
What I did was first remove the red cable from the molex connectors, completely. Throw it away.
Then take the molex pin, on the male side where the black wire of the 3 pin adapter is connected, pull it out, and push it into the slot where the red line just was.
Take the other end of that black wire and also move it into the spot on the other, female molex where the red wire was.

So it looks like this:

--black-- (female ----black---- (male
(3pin ) molex) ----black---- molex)
----empty---
---red--- ----yellow---

(edit: damn, the board really messed up my formatting sorry - youll figure it out!)
So this method uses less pieces, that's the only benefit I guess. Then plug the fan into the 3 (really 2 pin) header on this adapter and it runs at 7v. I guess this also makes the male end a 7v connection as well, if you have other fans that are female molex.