high frequency intermittent noise

kosst_amojan
516 posts 11-14-2017 4:03am

I’m virtually 100% certain that’s cell phone signal interference. That is exactly what an LTE signal sounds like when it’s being picked up by an unshielded/under-shielded wire in the signal path. I doubt it’s being picked up through the power lines, but I can’t be curtain. If it was, you’d hear it through your TV and computer. I’d be looking at interconnects.

When I first read the OP I though the same thing. It’s the cell tower or an antenna on the cell tower for some other type of technology company. But then I started reading what others had posted. Then I read Al’s (almarg) post and james1969 response.

Another thing that I didn’t think that fit it being the cell tower. If it is an antenna transmitting the signal why wouldn’t it be a constant repeating signal that would recycle itself 24/7? I then listened to the signal in the OP all the way through. It starts out as having a repeating cycle but about around half way through it peters out. Would that be typical of an LTE signal?
https://clyp.it/4b233bmm

For what it’s worth when james1969 brought into the conversation about the subway that runs beneath the building, he lives in, and said he thought there might be a correlation between the noise he is hearing through his audio system and the subway train passing by below I had a moment of deja va. Several years ago there was a posted message where a guy was having a similar noise problem as the OP here is having. He too had the subway running under his building. What are the odds?

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?

@james1969

I also have another receptacle outlet on order as well, as I will be changing the outlet receptacle from a 15 amp to 20 amp outlet receptacle. This is so I can plug the Furman P-2400 IT into the wall.

Is the branch circuit that feeds the duplex receptacle outlet a 20 amp, or is it a 15 amp? Go to the electrical panel and look at the handle on the breaker that feeds the circuit. It will say 15 or 20.

It's 15.

@james1969

99% chance the wire is #14awg. It is rated for 15 amps.
Just a guess the circuit is a convenience outlet branch circuit that feeds several other wall outlets in the room. Maybe even some ceiling lights. Have you ever checked what all is connected to the same circuit when you shut off the breaker to change out the outlet?

When you changed out the outlet for your audio system was there only the two wires inside the box that connected directly to the duplex receptacle?
Do you remember what the 2 wires looked like? was the insulation on the wires made of PVC/plastic one black, maybe red, and the other white? Do you remember how the plastic insulation looked? Was the white wire discolored kind of yellowish at the end that terminated, connected, to the receptacle. Was the insulation of either wire discolored, possibly caused by heat over the years.? Did the insulation look or seem to be hard or brittle?

.

Or did the 2 wires appear to have a cloth covering over what appeared to be rubber? One wire was black and the other was white or appeared to be white? What condition would you say the insulation was in?

I realize I am off subject with this post. I just finally got around to looking at your system on your system page. That’s a really nice system to be fed from a 15 amp convenience outlet circuit.

Jim