[Elecraft] annoying resonance with internal speaker in K3

[Nick-WA5BDU]

I've got this too. I did some things to eliminate top cover resonances 
and then I began to notice this.  It's a little more subtle than a 
continuous buzzing along with the tones of CW. Sort of a scratchy sound. 

I thought it was in the audio, but no, it's gone when I use headphones 
or an external speaker.  I thought it might be an artifact of 
processing, but no, it's still there when I turn processing off.   Band 
noise is enough to cause the sound on a moderately noisy band (not hard 
to find these days).  Moderate (but not excessive) volume is required to 
being it in.  I did note that as I crank up the Lo Cut, the noise 
disappears when I cross 250 or 300 Hz. 

Thus far, I've removed some of the things I did to dampen the top cover 
plate.  I removed the top and looked for any loose screws and tapped 
various components for sound.  Removed the bottom cover and attempted 
the same.  No luck.  I hate the thought of disassembling the entire 
front of the rig ...

73--Nick, WA5BDU


Fern Rivard wrote:
>     I have a K3 serial #412 which has always had an annoying resonance from the internals of the radio cabinet somewheres when using the internal speaker. I thought that it may have been the top lid which did that so I tried to isolate the top lid by temporarily adding some electrical tape between the top and when it meets the the top of the radio. However, that did NOT accomplish anything for me. Has anyone found a permanent cure for that annoying resonance? 
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