In the process of chasing a glitch

I was looking for this leading edge keying glitch on the Wien bridge audio oscillator:

the Wien bridge clicker

Haven't found the cause yet but I'll keep looking.

During the process of looking I happened to turn up the gain on the audio amplifier all the way.  Even though the oscillator was off and I wasn't doing any keying I was hearing a clicking sound.

2 clicks on the audio amp, 1st about 4 divisions from the left and the 2nd just after the midpoint

It wasn't anything on-the-second, there are about 10 clicks in 14 seconds, so close but it can't be a clock as such.

Then I turned off everything in the house except for the amplifier.  The lights, computers, router, everything off.  The click was still there

It then occurred to me that it might be an electric fence.  I turned on the K2 and tuned to 3550 and there it was.  Usually the noise blanker just wipes it away so I don't notice it.

electric fence clicks on about 3550 kHz about 5+ divisions apart, about 1.4 seconds

The weird thing is that  the sounds aren't coincident.  The click in the audio amp is just a beat slower.  I couldn't get a simultaneous scope picture of the audio amp and the K2 but did get this audio recording:

https://u.pcloud.link/publink/show?code=XZ2BokVZ6YltA6RnYzzu6IDrlVF36QBlvMHV

But the next morning the clicks are almost coincident:

https://u.pcloud.link/publink/show?code=XZOA7XVZbCsW5fbFTrJDdy0JSSjrbmuzlYKV

So I'm not sure what is causing the click.

This is a real mystery, not one of those TV murder shows where it always gets solved in less than 60 minutes.

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm