"WindsorFox[SS]" wrote in message
news:%bYZa.9210$qf.2506@lakeread06...
Trevor Wilson wrote:

**Oh, yes it is. Modern 12VDC fans use an internal oscillator,
driving a 3
phase, brushless motor. The only proper way to control the
speed is to vary
the frequency of the internal oscillator. That is a difficult
thing to do,
given that the circuitry is embedded.



Obviously you refer to somethin other than 12 Volt computer
fans.

FWIW, guys, and I don't want to get in the way of a good fight,
but we were talking about cooling fans for my Ampzilla, and it
turns out that Trevor was completely right that the fan in
question was 120VAC and not 12VDC. All the talk about regulating
computer fans is interesting, but not helpful with my problem. I
have a Zalman fan mate on my Zalman CNPS-7000-Cu, and it works,
but not over nearly the sort of range of speeds that Trevor is
talking about. Oh jeez, now you have me following off topic as
well.

Anyway, to paraphrase what I wrote earlier:
Digikey carries fans from Papst/ebm Industries. I found the
115VAC
model 4800Z for just under $30, plus about $4 for shipping. It
moves 56CFM at 28dBA. Mouser carries some ebm stuff as well, but
seems to have higher prices and a slightly smaller selection.

Is this a good place for me to stop looking and start acting? The
price seems a bit much but if it is quiet without the need of a
resistor, it should at least solve all of my problems. I've found
a few other 115VAC fans, but all seem to have quite a bit higher
CFMs and dBAs.

This is a power amp we are cooling here, not a computer. I am
leaning more and more to the opinion that a quality quiet fan
should be my first step, and that it just might turn out to be my
last step as well.