[Elecraft] KPA500 thermal clicks

[Martin Sole]

I think it sounds "orrible!". I'm quite used to the low rumble of the 
blower in my Alpha 77D but that ticking would be like Chinese water 
torture to me. Listening to an individual tick it does seem to have a 
ring to it. Okay the recording was perhaps not the most acoustically 
perfect but it certainly does sound as if the ring is from the source 
and not any sort of artifact. If it is from the source then I think you 
can probably find a way to damp it. First trick will be to identify the 
specific source.

I had read other comments about a ticking, always imagined it to be 
minimal and essentially unobtrusive but if what you have recorded is 
anything like how it sounds sat in front of it then definitely it does 
sound pretty bad to me and not just in amplitude but also in its timbre, 
pitch, and repetition rate.

Martin, HS0ZED


On 19/07/2018 06:25, ANDY DURBIN wrote:
> I placed my Android phone on top of my KPA500 and made a recording while making a few cycles of FT8 TX/RX.  The audio files can be found here:
>
> https://www.dropbox.com/sh/amfy3dz8pgl083n/AAAKi2GYripXyIDjiLpJ2hDwa?dl=0
>
>
> One file is the raw recording.  The second has been processed in Audacity to amplify to 0 dB peak.  The file starts before the first TX. Next the hum of the transformer can be heard with FT8 modulation in the background from TX moni.   As the recording progresses the changes in fan speed can be heard.   The click are always well above the fan noise.
>
> I used this recording to perform some spectral analysis of the clicks.  I took one sample at the click and another sample of the noise just before the click.  I then subtracted the noise from the click and I think I have a reasonable click signature to use as a baseline for evaluating any mechanical changes I make in an attempt to reduce the clicks.
>
> Crank it up and enjoy, especially if you think it's normal.
>
> 73,
> Andy k3wyc
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