[SOLVED] Fan hub for 3-pin fans, will it work?

karthik.gems

Prominent
Nov 5, 2018
61
1
535
0
I have a cooler master mb511 case which came with 3 front intake fans. But they have 3-pin connectors only and won't work in pwm obviously.

The store person has assembled my pc. He used a molex cable connector to power the fans. Since there is no connection to the motherboard, those 3 fans run at full speed.
My main issue is, the molex cable is too long and cramped up the space inside.

1. So can I use a simple fan hub like this and remove the molex cable from the psu completely? Nothing else is using this molex cable except those fans.

I understand I can't control the speed even with this fan hub. But my motherboard's (B450 Tomahawk Max) fan headers can work in both pwm and dc mode.

2. So apart from using a fan hub like that, is there a better way, to control speed as well? I know there is a possibility of using fan splitters, but those 3 fans take nearly 1.2 amps and I heard 1 header can only support 1 amp each.
 
Thanks for that photo. Problem appears to be that the actual Model Number is not among those markings. I can't find exactly which Cooler Master fan this is on their website, so let me ask a couple more questions to narrow it down.

  1. You call them 3-pin fans. There's a potential for confusion with RGB fans. Look at the cable for the fan MOTOR, which ends in a small standard fan female connector about 8mm (5/16") wide with three holes, and two ridges along one side. OR it may have four holes and be more like ½" wide. This is how we distinguish between 3- and 4-pin fans, so how many holes in that connector?
  2. The other cable for RGB lighting will have a much wider female connector that plugs into an RGB header on your mobo. This may have 4 holes in a straight line - that's for a plain RGB system that uses 12 VDC. The other possibility is that it has space for four holes, but one (the second location from one end) is blanked off - that's a 3-pin ARGB connector for Addressable RGB that uses 5 VDC power. Which do you have?
  3. When the lights are working, how do they appear? It might be
(a) LED Fan - only one colour on a fan, always on, although it might get dimmer as the fan runs slower;
(b) Plain RGB fan - each fan's colours change over time and include many colours, but at any one moment all the lights in a fan are the same colour; or,
(c) Addressible RGB (or ARGB or ADDR RGB) fan - each fan's colours change over time and include many colours, and at any one moment one fan may have many different colours simultaneously.

These will help me narrow it down.

I will tell you a preliminary bit of info. Masterfan specs for the fan MOTOR often include both a max running current and a "Safety Current" This latter spec is the max current the fan might draw briefly in abnormal circumstances like a fan stalled by being jammed, and such fans often have a built-in protection circuit to prevent damaging the windings under those conditions. They also publish for their RGB and ARGB fans the max current fo the LED lights separate from the motor current max. Of these three specs, it is only the normal max motor current (not the Safety Current) that is used for calculating loading of the mobo header. Many of their fans have a Safety Current rating of 0.37A, but a max normal motor current of 0.25 A or less.

Now, subject to further info gathering IF it turns out that your three front fans ARE 3-pin ones for motor power and control, and have normal max current specs under 0.33 A, then you can use a Splitter to connect the front three to a single SYS_FAN header. That Deepcool FH-04 device you linked to in point 1 of your first post will do this job. In my way of naming, that really is a SPLITTER, not the Hub the makers say. To me, a HUB must have an extra cable "arm" that plugs into a PSU output to get constant 12 VDC power to be distrubuted to its fans, and a HUB cannot control speed of any 3-pin fan. But that FH-04 unit has only a connection to a mobo header, so it will distribute to its fans only the power it gets from that header. If the header is configured to use DC mode suited to control 3-pin fans, then that WILL control such fans when using this Splitter.

If you do that, then you can connect the fourth 3-pin fan plus the added 4-pin fan to other SYS_FAN headers, and configure the one for the 4-pin fan to use PWM Mode.
 
You have 3x 3pin case fans.
Your motherboard has 5x 4pin fan headers. 1 - for cpu, 1 - for pump and 3 - for case fans.
You can connect all your case fans to motherboard and get them regulated with DC regulation method.
No fan hub necessary.
 

karthik.gems

Prominent
Nov 5, 2018
61
1
535
0
You have 3x 3pin case fans.
Your motherboard has 5x 4pin fan headers. 1 - for cpu, 1 - for pump and 3 - for case fans.
You can connect all your case fans to motherboard and get them regulated with DC regulation method.
No fan hub necessary.
Wait what? Can I connect a normal fan to pump header?
 

karthik.gems

Prominent
Nov 5, 2018
61
1
535
0
It's not that it can't. It shouldn't.
Pump is recommended to be run at constant speed.

You have to check available options in your BIOS for pump header speed regulation.
I just checked for bios options and the manual. I think we can control the fan speed as well when connected to pump header, as it shows pwm and dc options as well. Thanks a lot for ur time and help.

One last question, if you don't mind.

All these 5 fans have rgb. What actually powers the rgb in the fans?
I'm searching for the answer. Some people say, fan header itself lights up the rgb and rgb header is only useful to just control what color we want. Some said rgb header lights up the rgb. Which is correct? (This qstn is bcz each header supports only 3A max)

Since now I'm connecting nearly 4 fans in dc mode (by regulating voltage), I hope it doesn't affect the overall system voltage like +12v or +5v etc. Let me know.
 

lordmogul

Honorable
Jun 14, 2014
369
6
11,165
151
I got 3 fans running over a splitter on a single connector from the motherboard in DC mode for close to 6 years without issues.

for the RGB, guess that depends on how the manufacturer implemented it.
  • They could power the LEDs over the "normal" plug and just do some controlling over the RGB header
  • Or they could power and control it through the RGB header.
You would need to find the actual model of the fans to check that.
 
There are several sources of confusion you are dealing with.

Mobo fan HEADERS generally can apply automatic control of their fan's speeds, but details are important. In each case there is a temperature sensor associated with the header, and the control system changes fan speeds to keep the measured temperature at that sensor at the right level. For the CPU_FAN header, the sensor is one inside the CPU chip included by the chip maker, so this header ALWAYS should be used for CPU cooling. For the SYS_FAN headers, they all are based on a sensor on the mobo placed where the mobo maker judges is critical to control heat, so it is these SYS_FAN headers that should be used for case ventilation fans. Your PUMP header is different because its automatic control feature is basically disabled so that the PUMP (if you have one) always gets full 12 VDC power and runs full speed, as most pumps are designed to do. So, connect your CASE VENT fans to the SYS_FAN headers. Your mobo has FOUR of these according to the manual. Further, the manual says that these four are set by default to use the older DC Mode, although you can change to PWM. Check in BIOS Setup how they are configured.

With three front fans and four SYS_FAN headers you don't need any Splitter or Hub. BUT the SYS_FAN1 and SYS_FAN2 headers are nearer to the back of the mobo, so if your fan cables can't reach one of the you might need a simple fan EXTENSION cable.

You have not told us the exact maker and model number of those fans, although I gather you can read a label on them. That info would help. But in general, it is rare to have a RGB fan that uses 0.38 A max current. That's a lot, BUT there are other types of fans - the LED Fans, not RGB Fans - that have only ONE colour of LED in them and may well pull that kind of power. One quick way to tell, besides finding the model number and finding its specs, is the number of CABLES on each fan. A simple fan, or a LED Fan, will have only ONE cable that supplies power to both the fan motor and the LED's in the frame, if any. An RGB fan has TWO cables - separate ones for the motor and the RGB LED's in the frame. In an RGB fan (there are two incompatible types) both power supply and display control of the RGB lights is done by the second cable, while the first powers and controls only the fan motor.

If you give us the fan model and maker, we can look up detailed specs and advise how best to connect them.
 

karthik.gems

Prominent
Nov 5, 2018
61
1
535
0
There are several sources of confusion you are dealing with.
I actually wanted to message you to help me with this. I've read several posts of urs and I truly appreciate ur knowledge.

Your PUMP header is different because its automatic control feature is basically disabled so that the PUMP (if you have one) always gets full 12 VDC power and runs full speed, as most pumps are designed to do.
I experimented with pump header yesterday and observed that it runs normal fans at full speed as u said. There is no option to control it manually, so I will leave the pump header alone.

So, connect your CASE VENT fans to the SYS_FAN headers. Your mobo has FOUR of these according to the manual. Further, the manual says that these four are set by default to use the older DC Mode, although you can change to PWM. Check in BIOS Setup how they are configured.
Yes, I have tinkered with many settings when I bought my pc and learned a few things. I observed that these 3-pin fans can be controlled only in dc mode. Sadly my case came with 4 non-pwm 3-pin fans. I bought one pwm fan to keep for top exhaust.

With three front fans and four SYS_FAN headers you don't need any Splitter or Hub. BUT the SYS_FAN1 and SYS_FAN2 headers are nearer to the back of the mobo, so if your fan cables can't reach one of the you might need a simple fan EXTENSION cable.
My mobo (B450 Tomahawk max) has 4 sys_fan headers and my case now has 5 case fans :(

You have not told us the exact maker and model number of those fans, although I gather you can read a label on them. That info would help. But in general, it is rare to have a RGB fan that uses 0.38 A max current. That's a lot, BUT there are other types of fans - the LED Fans, not RGB Fans - that have only ONE colour of LED in them and may well pull that kind of power. One quick way to tell, besides finding the model number and finding its specs, is the number of CABLES on each fan. A simple fan, or a LED Fan, will have only ONE cable that supplies power to both the fan motor and the LED's in the frame, if any. An RGB fan has TWO cables - separate ones for the motor and the RGB LED's in the frame. In an RGB fan (there are two incompatible types) both power supply and display control of the RGB lights is done by the second cable, while the first powers and controls only the fan motor.
I have observed the specs of the fan at the back and seen that it takes 0.37A. It comes with two cables, one for rgb and one for fan.
I am guessing the 2nd cable is responsible for rgb lights, as when I unplugged those cables from mobo, the lights are gone but fans are still running (fan pins are connected with molex to psu).

If you give us the fan model and maker, we can look up detailed specs and advise how best to connect them.
Here is a photo of the back of the fan with specs, model and amps rating. There are 3 such fans at the front in my case. All are 3 pin fans.
 
Thanks for that photo. Problem appears to be that the actual Model Number is not among those markings. I can't find exactly which Cooler Master fan this is on their website, so let me ask a couple more questions to narrow it down.

  1. You call them 3-pin fans. There's a potential for confusion with RGB fans. Look at the cable for the fan MOTOR, which ends in a small standard fan female connector about 8mm (5/16") wide with three holes, and two ridges along one side. OR it may have four holes and be more like ½" wide. This is how we distinguish between 3- and 4-pin fans, so how many holes in that connector?
  2. The other cable for RGB lighting will have a much wider female connector that plugs into an RGB header on your mobo. This may have 4 holes in a straight line - that's for a plain RGB system that uses 12 VDC. The other possibility is that it has space for four holes, but one (the second location from one end) is blanked off - that's a 3-pin ARGB connector for Addressable RGB that uses 5 VDC power. Which do you have?
  3. When the lights are working, how do they appear? It might be
(a) LED Fan - only one colour on a fan, always on, although it might get dimmer as the fan runs slower;
(b) Plain RGB fan - each fan's colours change over time and include many colours, but at any one moment all the lights in a fan are the same colour; or,
(c) Addressible RGB (or ARGB or ADDR RGB) fan - each fan's colours change over time and include many colours, and at any one moment one fan may have many different colours simultaneously.

These will help me narrow it down.

I will tell you a preliminary bit of info. Masterfan specs for the fan MOTOR often include both a max running current and a "Safety Current" This latter spec is the max current the fan might draw briefly in abnormal circumstances like a fan stalled by being jammed, and such fans often have a built-in protection circuit to prevent damaging the windings under those conditions. They also publish for their RGB and ARGB fans the max current fo the LED lights separate from the motor current max. Of these three specs, it is only the normal max motor current (not the Safety Current) that is used for calculating loading of the mobo header. Many of their fans have a Safety Current rating of 0.37A, but a max normal motor current of 0.25 A or less.

Now, subject to further info gathering IF it turns out that your three front fans ARE 3-pin ones for motor power and control, and have normal max current specs under 0.33 A, then you can use a Splitter to connect the front three to a single SYS_FAN header. That Deepcool FH-04 device you linked to in point 1 of your first post will do this job. In my way of naming, that really is a SPLITTER, not the Hub the makers say. To me, a HUB must have an extra cable "arm" that plugs into a PSU output to get constant 12 VDC power to be distrubuted to its fans, and a HUB cannot control speed of any 3-pin fan. But that FH-04 unit has only a connection to a mobo header, so it will distribute to its fans only the power it gets from that header. If the header is configured to use DC mode suited to control 3-pin fans, then that WILL control such fans when using this Splitter.

If you do that, then you can connect the fourth 3-pin fan plus the added 4-pin fan to other SYS_FAN headers, and configure the one for the 4-pin fan to use PWM Mode.
 

karthik.gems

Prominent
Nov 5, 2018
61
1
535
0
Thanks for that photo. Problem appears to be that the actual Model Number is not among those markings. I can't find exactly which Cooler Master fan this is on their website, so let me ask a couple more questions to narrow it down.

  1. You call them 3-pin fans. There's a potential for confusion with RGB fans. Look at the cable for the fan MOTOR, which ends in a small standard fan female connector about 8mm (5/16") wide with three holes, and two ridges along one side. OR it may have four holes and be more like ½" wide. This is how we distinguish between 3- and 4-pin fans, so how many holes in that connector?
  2. The other cable for RGB lighting will have a much wider female connector that plugs into an RGB header on your mobo. This may have 4 holes in a straight line - that's for a plain RGB system that uses 12 VDC. The other possibility is that it has space for four holes, but one (the second location from one end) is blanked off - that's a 3-pin ARGB connector for Addressable RGB that uses 5 VDC power. Which do you have?
  3. When the lights are working, how do they appear? It might be
(a) LED Fan - only one colour on a fan, always on, although it might get dimmer as the fan runs slower;
(b) Plain RGB fan - each fan's colours change over time and include many colours, but at any one moment all the lights in a fan are the same colour; or,
(c) Addressible RGB (or ARGB or ADDR RGB) fan - each fan's colours change over time and include many colours, and at any one moment one fan may have many different colours simultaneously.

These will help me narrow it down.

I will tell you a preliminary bit of info. Masterfan specs for the fan MOTOR often include both a max running current and a "Safety Current" This latter spec is the max current the fan might draw briefly in abnormal circumstances like a fan stalled by being jammed, and such fans often have a built-in protection circuit to prevent damaging the windings under those conditions. They also publish for their RGB and ARGB fans the max current fo the LED lights separate from the motor current max. Of these three specs, it is only the normal max motor current (not the Safety Current) that is used for calculating loading of the mobo header. Many of their fans have a Safety Current rating of 0.37A, but a max normal motor current of 0.25 A or less.

Now, subject to further info gathering IF it turns out that your three front fans ARE 3-pin ones for motor power and control, and have normal max current specs under 0.33 A, then you can use a Splitter to connect the front three to a single SYS_FAN header. That Deepcool FH-04 device you linked to in point 1 of your first post will do this job. In my way of naming, that really is a SPLITTER, not the Hub the makers say. To me, a HUB must have an extra cable "arm" that plugs into a PSU output to get constant 12 VDC power to be distrubuted to its fans, and a HUB cannot control speed of any 3-pin fan. But that FH-04 unit has only a connection to a mobo header, so it will distribute to its fans only the power it gets from that header. If the header is configured to use DC mode suited to control 3-pin fans, then that WILL control such fans when using this Splitter.

If you do that, then you can connect the fourth 3-pin fan plus the added 4-pin fan to other SYS_FAN headers, and configure the one for the 4-pin fan to use PWM Mode.
Hi, thanks for the reply.
I don't have any confusion over the fans and their cables. The 3 pins cable with 2 ridges plugs into fan headers and the fans run normal. The other cable has 4 pins which is for rgb, not argb. The lights on these fans are not individually addressable. I can use the motherboard's software and change colors but all fans exhibit same color when changing colors. Means if i we pick red, all fans show red; if we choose white, all fans show white.
This is a typical 12V rgb 4 pin cable. Not argb (5v).

I was not able to find any info in the internet about those specific fans. There is no model number anywhere mentioned, except that there is that sticker with specs on the back of the fan and I shared the same with you.

I've looked up in partpicker.com reviews and there is one person who mentioned he uses splitter for these 3 fans.

So is it good to buy a splitter or shall I go with that specific hub of deepcool I mentioned ?
 
Last edited:
Actually, as I said above, the Deepcool FH-04 unit IS a SPLITTER as I label them. That is, it does NOT supply to its fans a fixed +12 VDC power source on Pin #2 drawn from the PSU. And it does NOT depend on each fan to be a true PWM 4-pin fan able to use the PWM signal on Pin #4. What it does do is connect all its fans in parallel to the Ground and +DCV lines coming from the mobo SYS_FAN header. That means the the voltage each fan receives from Pin #2 is the VARYING voltage that the SYS_FAN header sends out IF that header is set to use DC Mode and NOT the new PWM Mode. So this FH-04 unit CAN allow the header to control the speed of your 3-pin fans. Go ahead and use it.
 

karthik.gems

Prominent
Nov 5, 2018
61
1
535
0
Actually, as I said above, the Deepcool FH-04 unit IS a SPLITTER as I label them. That is, it does NOT supply to its fans a fixed +12 VDC power source on Pin #2 drawn from the PSU. And it does NOT depend on each fan to be a true PWM 4-pin fan able to use the PWM signal on Pin #4. What it does do is connect all its fans in parallel to the Ground and +DCV lines coming from the mobo SYS_FAN header. That means the the voltage each fan receives from Pin #2 is the VARYING voltage that the SYS_FAN header sends out IF that header is set to use DC Mode and NOT the new PWM Mode. So this FH-04 unit CAN allow the header to control the speed of your 3-pin fans. Go ahead and use it.
Thank you. My confusion is cleared. The hub is not available here suddenly. So I ordered this 1 to 3 splitter cable. I will let you know how it turns out.
 

karthik.gems

Prominent
Nov 5, 2018
61
1
535
0
Yes, that will do the job well.
Thanks a lot for your help and time. That cable worked good enough and now I can control those fans in DC mode. I kept that around 7 volts and fans are running fine. Surprisingly all that fan noise which was earlier present, is now half gone. I will upgrade to some good pwm non-vibrating fans after a while. Thanks again.
 

ASK THE COMMUNITY

TRENDING THREADS