Do you have the full design parameters for the KPA500 cooling, air flow
required at specific temperatures to protect the MOSFETs, current and
voltage capable of being delivered by the KPA500 circuits to the fan at
each of 3 fan speeds? I certainly do not have those parameters. That
information would be required to make any intelligent swap of the fan.
I would not know what parameters would qualify a fan to be of higher
quality than what is in there already- Greater air flow usually means
more noise, and could mean more current draw.
A lower fan speed would be less noisy, but would likely reduce the air
flow and cause greater heating of the MOSFETs.
I do not think changing the fan would be a task to be taken lightly,
there are too many factors at play.
Sending the KPA500 back to Elecraft because the 'new improved' fan
needed more current than the KPA500 could supply, or sending it back to
change the PA sandwich after installing a slower fan (or one with a
lower blade pitch) that was more quiet, but failed to move enough air
could become an expensive task.
73,
Don W3FPR
On 6/3/2014 10:19 AM, Harry Yingst via Elecraft wrote:
I would tend to believe that replacing the cheap fans with
higher quality fans would be a improvement in design.
If the K3 cannot handle what little extra current draw the fans have
then I would certainly question the well engineered aspect of it.
As in any product cost is a factor and I'm sure Elecraft
has to weigh the cost associated with various parts.
For many the noise will not bother them for others it will so for the ones
who do find the additional noise bothersome they can simply swap out
the fans for a higher quality fan and enjoy the reduction in fan noise.
To my ears (and I'm partially deaf from when I was in the Navy) the stock
fans in the K3 had a grating sound that added to the background noise.
Replacing the fans was a worthwhile improvement and made copy easier.
I'm not afraid of improving a design where there is room for improvement.
________________________________
From: Jim Brown <[email protected]>
To: [email protected]
Sent: Monday, June 2, 2014 11:16 AM
Subject: Re: [Elecraft] KPA-500 fan noise
On 6/2/2014 7:56 AM, AG0N-3055 wrote:
You could always try replacing the fan with a quieter fan.
I would consider that myself, but only with one recommended by the good people
at Elecraft.
It is generally a bad idea to try to re-engineer a product, especially
one that is well designed. In this case, I would consider it a really
bad idea.
73, Jim K9YC
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