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.
128x128Ag insider logo xs@2xjames1969
@jea48   

No headphone output on my preamp.  

I just dug out my pro-audio monitor too, plugged it into a different circuit and could hear the noise, though not as loud, and nothing was plugged into the monitor either, it was simply plugged into the wall.
I found this: http://blog.rfvenue.com/2015/05/06/how-to-prevent-cell-phones-from-interfering-with-audio-equipment

It talks about cell phone noise in a pro audio setting, and mostly with phones as the source of the noise, not a cell tower. But they do mention a way to get rid of the noise that hasn't been mentioned yet. It wouldn't be the best fix, but could at least let you see if it's coming through the RCA cables. Their fix: ferrite beads on the input cables, close to the end that plugs into the amp. The article recommends specific ferrite parameters to address cell phone noise..
If ferrites on your IC cables solve the problem, you could look at more heavily shielded ICs. If not, you're only out the cost of ferrites..
@toddverrone

That’s a great find. Let’s say I get ferrite beads in place. I still have tubes out in the open where the audio signal goes through as well. I think there is no escape...
@kosst_amojan- is it possible that the building itself is set up with these devices you identified? (They seem to act like repeaters, to increase strength within buildings). Unless a neighbor set one up to improve his/her cell reception, as @jea48 alluded to, why wouldn't the building itself provide such a facility? Given the density and height of the buildings in Manhattan, I remember encountering dead spots in coverage walking around on the streets (granted, this was some years ago, I haven't done that for quite a while, and now no longer live or work in NY). 
Here is another recording taken early in the morning with no subway cars under my building:

https://clyp.it/ae0xgczb

Note there are 2 noises:
  1. The consistent hash/whine
  2. The intermittent noise
This is the worst I've heard it in the mornings.  It only lasted for a minute and a half, enough for me to record the 1 minute clip.

The Furman has buffered me from my refrigerator noise, I would hear a *click* in my system when the refrigerator would turn on, now it's silent.