120mm Fan Testing on an MCR120 Radiator Round 6

[jalyst]

Hey folks,
Just a few older posts missed by some of you, plus some newer ones I'm responding to.
Bing, if you got a minute could you please respond to these two (below):

Why not connect each PWM fan to each of the PWM fan-headers instead of just one PWM header?
I have 2x PWM headers and will probably only have 2x PWM fans, the rest will be AP-15 & 14, which I believe are not PWM.
That way each fan gets power & passes/receives RPM/PWM signals independently of one another.
Of course any fan/s that are too powerful for the mobo's power regulation would need their +/- wires rigged to a molex connector.
And then be connected directly to the PSU, but otherwise....

Wouldn't it be better to have discrete RPM sensing for each individual fan?
e.g. if you have 4 fans on the rad, but all 4 fans are represented by only one RPM sensor, then you wouldn't always know if one fan dies!
I guess that's just the limitation of not having enough headers, sigh, perhaps longer-term I'll need a multi-channel fan controller.

You can see in a video I made for bing....the PWM version runs at about 2400rpm at the lowest duty cycle with Gigabytes CPU header....but with a proper PWM controller, at 0% duty cycle, the PWM version will run at about 1000PRM.....so, if you want the best, petition Scythe for the PWM version

Does this mean that if I try to run 1-or-more 5400RPM PWM GT's, off 1-or-more of my MB's PWM fan-headers...
That I also won't get decent PWM control w/a duty cycle at 0%, & hence won't be able to lower it to 1000RPM?

Regarding using 3pin fans in a MB controlled system. I think it's possible looking at the 3 pin pwm controller I built from pcbheavens design. If I understand it right, it basically takes a PWM signal from the 555ic and uses a power mosfet to amplify it. Seems logical you could do the same thing to a motherboard pwm signal. Just need a mini circuit that draws 12v from a molex connector, and convert the MB signal to 3 pin PWM. That might be just the ticket in converting MB temperature control over to auto adjusting your favorite 3 pin fan.

Aren't motherboards with 3-pin headers essentially linear voltage controllers?
So any fans with 3-pins, you could just sit em on those headers.
Then you could up/down speed in a similar fashion to PWM, just not as efficiently?
And you could still get RPM feedback etc...

PWM
Yes, I think it can be done wih just one 4 pin MB header. If I understand the circuit, the power mosfet just sort of works like a relay (A switching power supply). Each MB PWM pulse simply activates the mosfet gate drawing power from the other power source(molex), so the power limit is really a function of the mosfet. I think with the right circuit and perhaps multiple mosfet and heatsinks on those mosfets, you could probably thermally drive as many fans as you want from a single MB header. It would only use the pwm signal to activate the power mosfet..the power would draw from the molex/power supply. You can do this same thing now using 4 pin pwm fans, you just have to wire the red and black over to the molex (same thing as the new swiftech PWM pumps).

So you're saying that with this circuit...
One can have higher wattage PWM fans coming-off any 4-pin PWM header it's rigged to, than would normally be possible?
(I got 2x 3-pin and 2x PWM 4-pin)
Why not just connect the higher wattage fans directly to the PSU, does it get too messy?

Soo..yes a PWM fan is 4pin (power,ground,rpm,pwm sensor), but you can make a 3pin pwm fan controller..there is a downside though...no more RPM readout.
I just really want to explore a thermally controlled pwm setup and it would be great if I could just reuse my 3pin fans. It just doesn't make sense to run fans at full speed all the time or manually controlled. Let the motherboard do the work adjusting. Sure you can buy fan controllers that do this too, but I'd like to make my own as a fun project..

I'd love if there was a way to make all headers on my mobo PWM-capable, but in doing so retain compatibility with any 3-pin fans.
And hence have the choice of whether I want to keep RPM monitoring for those fans, or drop it so they can have PWM!?

Thanks all.