Help identifying Tuner noise

Thanks Newbee, but I'm getting a strong signal and my Tuner is very sensitive. It's not hiss, and it does sound like in you're in a field of locusts or maybe cicadas. The intensity of this noise varies, and right now it's gone!

I've done all the internal tests for related equipment, power, transformers, dimmers, furnace, washer/dryer, cordless phones, and wireless network. The sound is also present whether muting is switched in or out, but the sound does disappear when I switch to Mono.

Earlier, when I switched Muting in, the noise got louder and when I adjusted the muting sensitivity control on the back, I was able to get rid of the noise, I thought. Later, the noise would come back with muting in or out...then there would be no more noise.

I have been wondering if there's some kind of external interference causing the problem, but I don't know where to begin or how to test for such a thing.

No problem Newbee, I'm in the same boat!

Kirkus, thank you for the detailed and informative explanation. The tough part is that the Tuner was recently serviced, upgraded, and realigned by Sam Kim of Sam's Audio Labs, who's a guru especially with tuners. He thought that the tuner may now be too sensitive, and/or there may be an external source for the noise. Do you know where I can acquire that mod?

I will relay your explanation to Sam, so thanks again.