[Brad Winder]

Thanks for the help, morzh! I forgot to mention that I did pull the tubes, and the "clicking" is still present, unless I pull out the 42 .

But I got the probe I was building for my Eico signal tracer finished, and low and behold...the clicking noise comes through on the tracer, without the radio plugged in. So, I did some checking, and the noise is on the power line to my basement shop! But not present anywhere else in the house. My shop is on a sub panel, so that may be a cause. I have a my personal Sparky on the case. He thinks it may be an induced noise, from another line that crosses the supply to my panel. We'll see...

I may have isolated the voltage issue, however, after I followed your advice. I believe I may have a leaking mica cap, off the grid of the 77 tube.