[Elecraft] [K3] K3 fan noise, part XXLIV

[Joe Planisky]

That assumes that the airflow is the predominant source of noise.  In  
my case, the airflow noise is secondary to what I believe is bearing  
noise.  At low speeds, this "motor noise" is what I hear mostly.  It  
is the same across 2 sets of UTEC fans.

I've posted a recording of my K3 fans at http://www.jeffnet.org/~jplan  
if you're curious about what it sounds like.  (note: I'm not sure the  
embedding works, so there's also a download link.  It's a 4.1MB WAV  
file.)  That recording was made with an AKG C1000 mic about 2 feet  
directly in front of the K3, about where my head would be when  
operating.  Use headphones to get the full effect.

Of course, we can't tell anything about how loud it actually sounds  
from that recording since we have no idea of the gain between my mic  
and your ears.  I'm posting that recording to give an idea of the  
quality of the sound, not how loud it is.

I'd like to try a quality fan with sleeve bearings.  Sleeve bearings  
don't last as long as ball bearings, but they are quieter.

73
--
Joe KB8AP


On May 29, 2010, at 3:31 AM, Tom W8JI wrote:

> That isn't surprising. Fan mounts, although people really
> like to mess with them, almost never have a noticeable
> effect on noise.
>
> Other than the design of the fan itself, the number one
> thing that affects noise is having an object near the blades
> (especially out near the tips). Restricting the airflow also
> doesn't help. The worse thing to do for a given amount of
> restriction is place it on the fan inlet.
>
> I haven't played with a K3,  but cutting some thick spacers
> to move the fans outward from the PA might be worth a try.
> Cheap sound meters are readily available, and a good way to
> test.
>
> 73 Tom
>
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