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high frequency intermittent noise

I have a noise issue that is intermittent.  Here is what the noise sounds like:

https://clyp.it/4b233bmm

Here is what I know so far:
  • The sound affects all components and is compounded if all components are turned on.  I have turned off my preamp, phono preamp, leaving just my mono blocks on, and the noise still appears.
  • I have turned off everything and unplugged everything in the house including my dimmer switch, and the noise still appears.
  • I have a pair of pro-audio monitors, self powered with class AB amps, and when I plug those into the same outlet, I hear the same noise coming through the pro-audio monitor.  So this rules out my big system.
  • The noise is primarily during the day and goes into the evenings, weekends too, early mornings it does not appear.
  • I live in a pre-war mid-rise building.  I have no ground, I'm using a Nordost QKore grounding system.  This did reduce the noise floor quite a bit, but has no affect on this intermittent noise.
  • I have a cell phone tower directly across the street from my building in Manhattan.
  • Looking at a real time analyzer, I see peak at 2kHz when the noise appears.
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james1969 OP
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Seems like I have been in similar odds before.  Just this weekend I ordered some parts for my turntable from KAB USA, another person with the identical name was ordering parts as well and our orders got combined which turned into an administration mess for Kevin at KAB.  What are the odds?
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james1969 OP
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It's 15.
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james1969 OP
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@jea48

Yes, this is a dedicated circuit, I have tested for this.

When I changed out the outlet, there were 2 wires connected to the old receptacle: white and red. There is another black wire not being used. I didn’t want to touch that wire, since I don’t really know what I am doing, I just copied the previous installation, using only the red and white wires previously used. The insulation seems to be fair, it’s PVC/plastic and the white looks white and did not appear brittle.

I would say the insulation is in good condition.

I will have someone come in and take a look at the circuit, maybe it can be switched out for a 20 amp circuit. So far though, I’ve never tripped the circuit breaker, and my amps are class A.  Thank you for the kind words.
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