Please do a PWM fans roundup!

[pcy]

Hi,

What would be nice is a PWM relay controller.

It would plug into the mobo header and the PSU 12v, getting PWM info and adjusting the dc output from the PSU to match the mobo's intended PWM fan output.

Then we could run multiple constant dc fans at via mobo PWM control.

I don't understand why you want to use the 12V from the PSU iteself rather than the 12V of the fan header, which has plenty of current capacity and derives from the 12V of the PSU anyway.


The power limit of the "PMW relay concerter" which I call a PMW-DC converter is max current deom the final output transistor.

On the unit we make:
http://www.paqt.co.uk/docs/PaQ_PWM.pdf

this limit is 0.5A, or 6Watts at 12V.


A typical fan uses 2W or so at full speed, so running more thean two fans is going to be a problem, and trying to increase the power capability of a PWM-DC converter increases cost and complexity significantly. Two fans running at 12V is not going to qualify in the silence stakes either...



Peter

[Aris]

But, how do we KNOW that PWM makes fans noisier?

There have been fan reviews in the past at other sites pitting PWM and non PWM fans up against each other. Some fans on PWM do not exhibit increased noises over voltage regulation, but then on the other side of things fans on voltage regulatioin never exhibit additional noises over using them with PWM.

So while their may be some fans that are quiet both with and without PWM, all fans are guarenteed to be quieter without it.

[40974111]

My further 2 cents worth on the matter:

Arctic Cooling F12 Pro PWM = horrible (heaps of motor buzz, and their is also noise caused by the fan rotating at slower speeds, almost no vibration transfered to case with conventional screws, can only be used as an exhaust and only wiht conventional screws)

Arctic Cooling 12025 PWM = very good (slight motor buzz but only with ear within 10cm, and decently quiet - although gets loud above 1000 rpm)