"WindsorFox[SS]" wrote in message
news:zfYZa.9231$qf.1890@lakeread06

Ron wrote:

I wish I'd known how difficult controlling a 12VDC fan was;
I wouldn't have done it. I have two fans, fed by a self
designed and built controller.

Go here http://xoxide.com/fancontrollers.html and make your
choice of fan controllers...

Not to mention all the motherboards with fan controllers built in.

IMO anybody who says that applying speed controls to 12v fans are
ineffective because the range of speed adjustment is limited, is showing
their lack of practical experience. For one thing, the noise and air
movement coming off a fan is a very nonlinear function of speed, Turning fan
speed down to 40% may not seem like much on paper, but in the real world
it's very significant.

The difference between the same fan running at 5000 rpm and 2000 rpm is like
night and day. Furthermore, if you look at fans that have low noise
characteristics, the major difference is that they spin slower. Indeed, in
my investigations of quiet CPU coolers I found one product line that
provided a full range of cooling ratings (Molex), using heat sinks and fans
that were identical, other than fan speed.