[Elecraft] KPA1500 Power Supply Fan Noise

[Peter Hall]

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

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