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.

james196911-12-2017 2:30am

james1969 OP Details Discussions Posts This discussion Message User 347 posts 11-12-2017 at 02:43am Copy Comment URL Report Comment Edit Delete The noise is not affected by the volume.
james1969 OP Details Discussions Posts This discussion Message User 347 posts 11-12-2017 at 03:35am Copy Comment URL Report Comment Edit Delete This noise comes and goes apparently at random. I can go 15 to 20 minutes with out it presenting itself. Other times during high activity, it will last for 15 to 20 minutes at a time with shorter breaks. Early mornings it's very infrequent if not there at all. Usually by 11am it begins. I have neighbors above me, below me and to my sides. Who knows what kind of electronics, dimmers, appliances they have.
erik_squires Details Discussions Posts This discussion Message User 16,019 posts 11-12-2017 at 03:36am Copy Comment URL Report Comment Edit Delete Do you have any sort of Wifi or security system? Also disconnect incoming network and cable TV cords as well if any. If this is purely a power issue, in the audible spectrum, Furman power conditioners with LiFT and SMP are really really good for removing noise at an affordable price. Best, Erik
james1969 OP Details Discussions Posts This discussion Message User 347 posts 11-12-2017 at 03:55am Copy Comment URL Report Comment Edit Delete @erik_squires I unplugged my AV system completely, cable modem included. It was all off and unplugged. No affect. Thanks for the pointer to Furman, I'll check them out.