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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
jea48
2,944 posts
 
james1969 OP
267 posts                                                                          11-15-2017 4:12am

I just went looking for my pro-audio monitors and just realized they are downstairs in storage. I will dig them out if the Furman P-2400 IT has no affect. I will be receiving the unit today.

If this noise is coming from the cell tower, I don’t think there will be much I can do about it.

@randy-11

My Interconnects are single-ended RCA only. I cannot switch to balanced because my system does not support it. I can run balanced from my preamp to amps, but I do not have any XLR interconnects that long.

For now I wouldn’t go to the trouble of bringing one of them back up to your apartment for the test.

Just how long are your the RCA interconnects? How long are the speaker cables?
james1969's avatar
james1969 OP
345 posts
 
RCA interconnects range from 3 meters to 1 meter.  Speaker cables are 2.5 meters.
jea48
2,944 posts
 
@james1969

Any chance you have a radio that is AC 120V powered? If you do try the same test Al, (almarg) asked you to do in an earlier post. (Page one)

One other test you might try.
 You will need buy a pair of RCA shorting plugs.
Disconnect the interconnects from the back of the power amp/s and plug in the shorting plugs. Check for the RF signal noise.


 
james1969's avatar
james1969 OP
345 posts
 
The Furman P-2400 IT has no affect on the noise.

@jea48 

I do not have a radio that is AC powered.  I will look into the RCA shorting plugs.

I think this is an air borne issue - cell tower...
james1969's avatar
james1969 OP
345 posts
 
I put the PS Audio Noise Harvesters on the Furman P-2400 IT to see if they would stop blinking, they did not.  And when I turned on my light on a dimmer in the kitchen (different circuit), the PSNHs went crazy.  So does the Furman even do anything to filter noise?

The noise floor in the music has been lowered.  There is benefit sonically in the music though.
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