[Elecraft] KPA1500 Power Supply Fan Noise

Tue Jun 11 04:47:28 EDT 2019

Apparently I was not clear enough in my message.  It is the PSU fan noise
that is deafening, not the RF deck.  Like Peter, my PSU sits on the floor
underneath a wooden operating desk that holds the rest of the K-line.  The
noise from the PSU is high-pitched and piercing.  The only thing I can
liken it to is a four-rotor Mazda prototype IMSA GTP race car from the
early 90s.  Brain-piercing, tear-your-hair-out, heard-from-every
room-in-the-house louder than hell, and has been so since the day it
darkened my doorway--with the RF deck at idle.

73 Eric WD6DBM

On Tue, Jun 11, 2019, 12:54 AM Peter Hall <P.Hall at curtin.edu.au> wrote:

> Hello Eric
>
> There's no doubt that a KPA1500 physical installation needs some careful
> attention to the noise aspect.  That said, I'm a bit surprised by your
> problem with the PSU fan.  I can certainly hear mine but, overall, the
> noise is entirely dominated by the RF deck fans.  I've located the PSU
> under my operating desk, which is made of a dense particleboard material.
> The RF deck sits alongside my TS-890S transceiver on the desk.   I can hear
> the PSU fan if I put my head below desk level but, even then, I don't find
> the fan to be particularly high-pitched in its acoustic output.  Could you
> possibly have a faulty fan (maybe excess nearing noise)?
>
> On the other hand, I do find the RF deck fans test my patience a bit,
> especially since the last round of major firmware updates which start the
> cooling at a lower heatsink temperature.  That probably works well in a
> high-output environment, where it no doubt delays the onset of heat
> soaking.  But when the amplifier "loafs" in a low power, low duty cycle
> environment as it does in some of my applications. it just starts the noise
> prematurely.  It'd be great to see something like an "80m rag-chew" option
> for those times!
>
> 73, Peter (VK6HP).
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net>
> On Behalf Of eric norris via Elecraft
> Sent: Tuesday, 11 June 2019 7:57 AM
> To: lists at w2irt.net; lists at w2irt.net; Elecraft Reflector <
> elecraft at mailman.qth.net>
> Subject: [Elecraft] KPA1500 Power Supply Fan Noise
>
> More broadly, has there been any progress on reducing the piercing power
> supply fan noise on the KPA1500 when only using it as a tuner or an antenna
> switch?  I complained about this a year ago, and I find it completely
> unacceptable.  No set of noise-reducing headphones that I have tried works
> well enough to make the noise tolerable.  I've tried moving the PS deck
> around with minimal improvement.  This just doesn't seem to fit Elecraft's
> philosophy of a quiet operating environment.  Why do these fans have to
> operate at full throttle when there is minimal current draw from the rf
> deck?  Why do these fans create such a piercing high-pitched note? If there
> is no response from Elecraft, what have other ops done--short of moving the
> PS into an adjoining room--to mitigate the scream?
> Thanks,
> 73 Eric WD6DBM
>
> Sent from Yahoo Mail on Android
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