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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.
james1969
almarg's avatar
almarg
9,670 posts
 
AM is WAY too low in frequency. Cell phones broadcast in the 700 to 2100 MHz range.
Thanks for your informative inputs, Kosst. But of course the bandwidth of James’ audio components most likely extends only up to a frequency that is even lower than both the 540 kHz he had his radio tuned to and the 455 kHz IF frequency which I believe is used by AM radios in the USA.

So if cellphone traffic is indeed the source of the noise, his components are presumably responding to relatively low frequency modulations that are present on the near GHz carrier frequencies, which **might** also be picked up by an AM radio.

Regards,
-- Al

Post removed 
almarg's avatar
almarg
9,670 posts
 
...can an XLR, balanced input, be shorted out without causing any damage to the amp? My guess is yes it would be ok.
Yes, that should be ok to do, Jim. From the perspective of the amp, shorting the three pins on an XLR input connector together would not be much different than if it were to receive a zero volt signal from a preamp having very low output impedance.

Best regards,
-- Al

Post removed 
randy-11
1,913 posts
 
cell traffic is also likely very low in the early am when he rarely hears the noise

BTW, are your interconnects single-ended RCA type?  if so, can you switch to balanced or do the components only support SE?
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