Quieter Case Fans

[siox23]

finally I did some testing with this little PCB and a noctua nf12 pwm fan.

the good news:

it worked and the fan spins.

the bad news:

it spins with a constant rpm of 412.

with the apple fan connected I measure voltages between 0,8-12V on the speed control output pin of the motherboard (tuning with Mac fan control).

with the pcb and the noctua fan I have constant 12V on this control pin.

I think this could have to do with the to low idle speed of 412rpm (the delta idle speed is 600rpm) - the Mac is sending maximum voltage on the control pin to bring the fan to the idle speed of 600rpm and is probably overloading the vc input of the little controller board which accepts a max of 10V according to its specifications.

i will test further with resistors in series to bring down the voltage below 10V on the control voltage input.

 

[ctrlzone]

this is very interesting, please keep us updated!

 

[amedias]

The pinouts at this link you posted on the last page for 'Apple Motherboard 4 pin CPU PWM fan connector' do not seem correct to me...

IME its:

1 - GND
2 - VCC (12V)
3 - Sense/Tacho
4 - Apple control voltage 0->12V (need to get new multimeter to confirm it's 12V and no more)

I've just written up my info/experience here:

Mac Pro (4.1/5.1) aftermarket fans WITH automatic SMC control

I've been reading around this subject for a while as a pet peeve of mine is noisy computers. My normal workstations are entirely passively cooled and silence is bliss, but I do still use my cMPs when I need machines with a bit more power or more cores for testing virtual environments and the...

forums.macrumors.com

EDIT - see my last post in the above thread, I've got those converter boards working with my PWM fans with full SMC control. I need to test more fan models to see if it's consistent success but the 3 or 4 PWM fans I've tried work fine.

 

[siox23]

The pinouts at this link you posted on the last page for 'Apple Motherboard 4 pin CPU PWM fan connector' do not seem correct to me...

IME its:

1 - GND
2 - VCC (12V)
3 - Sense/Tacho
4 - Apple control voltage 0->12V (need to get new multimeter to confirm it's 12V and no more)

I've just written up my info/experience here:

Mac Pro (4.1/5.1) aftermarket fans WITH automatic SMC control

I've been reading around this subject for a while as a pet peeve of mine is noisy computers. My normal workstations are entirely passively cooled and silence is bliss, but I do still use my cMPs when I need machines with a bit more power or more cores for testing virtual environments and the...

forums.macrumors.com

of course you're right. I posted the link before I started testing and measuring the motherboard connector. should have mentioned it in my last post.

I can confirm that the pinout you posted is correct.

regarding the max V on the control pin: with full RPM set in macfancontrol I measured 12,2 V not more than 12,3V.

your idea to use the control pin on the fans supply voltage line is great! very easy solution. if I find time I will test if the noctua fan starts spinning even with idle rpm, which is in my case an equivalent of about 2-3volts on the control pin.