Hi all,

First, for you ADHD go-gettum problem solvers who like staring at funny graphs that aren't doing what they should be doing, the TL;DR: There's a funny electronic buzzing sound in all of my sensitive/expensive electronics and it's even gotten louder; please help me understand this reading on the oscilloscope, which I took on my 120v AC outlet. You will find it attached, please and thank you.

The "you got me I'm curious, I'll spend 15 minutes reading your 3 energy drink, 4 cold brew coffee inspired 11:00pm worknight post:"

The back story:
Loud (beyond normal) electronic buzzing sounds started to occur in all of my electronics that had any kind of main login board. These include, but are not limited to, LED lightbulbs, my oven, the refrigerator, both of my computer PSU's, TV's, Modem+Router, the list goes on. Please be aware that this sound is house-wide. Not just one circuit. Since I noticed this, I have been chasing electricians, I&C techs, the power company, my neighbors, and lately even the FCC/CC in circles trying to make heads or tales of the dratted electronic buzzing sound that has plagued my ears and, more importantly, my electronics.

What I've done:

I've been in and out of electrical help forums, student-engineer help-me-read-this-instrument pages, HAM radio operator and complainer pages, and at this point I feel like I've taken my first year of electrical apprenticeship online (kidding). Please send help, I'm an IT guy. We try NOT to touch the magic sparky stuff in the walls.

I've unplugged every item in the house trying to narrow down the source.
No, nothing was left plugged in (except the dryer, oven, and AC) when I finished.
Yes, everything still buzzed one by one as I plugged them each in to a different circuit in the house.

The electrician that I had out said that voltages across the house look fine. He also said that all of the breakers/protectors on the panel look and trip fine. For all purposes, he believes that the wiring and components of my house are not the issue, here. I don't know if I believe him, but he's the electrician, here, I just use the sparky zappy stuff.

Next, I had my power company out. Surprise, surprise, they found that voltages at the panel were fine. They said there's nothing more they can do and that the issue I was describing sounded like a power frequency issue and there's nothing they could do about that. Another dead end. The man left me at my doorstep to die a slow 30-year electrical buzzing induced death.

Next, I appropriated an oscilloscope from somewhere and decided to do my own testing on an outlet, during the daytime. Attached, you will find the day-time (problem existing) video. You will also find the video I took at dusk with the problem NOT being there, to capture a look at what my power usually looks like when not driving my senses nuts with infernal electrical whining.

Attached, you will also find a video of the sound as best I could capture it.

On that note, It's insanity to me that everywhere I turn has NO idea what I'm asking them to fix. No one seems to recognize that this IS an issue and it DOES need to be fixed. Am I the crazy one? I'm starting to think so. If you, dear helpful forum, have any advice on who/what I should turn to next, I'd definitely appreciate that, too.

Anyways, I think that's enough for this post. Please send help, I am not okay.

Edit: I have found that I cannot attach videos to forum posts.. As such, here is a link to a Google album containing the file: Oscilloscope Readings.
You can check the link before clicking it by hovering over it and looking in the bottom left of your screen. In that album, there is also the night-time reading that is normal (in my opinion) as well as the video/audio of what my buzzing electronics sound like.

Attached to the forum post will be a still of the oscilloscope reading, should you not want to trust the link. Please not that the graph itself is shifting rapidly left and right on my scope (I think this is indication of frequency?) and the jitter of voltage (?) in the line keeps moving up and down the diagonal portion.

My Request:
If nothing else, can someone please help me understand what I'm looking at on this oscilloscope? From my research, the yellow line = voltage. Peak to peak is the frequency. A moving peak = changing frequency. Jitters in the yellow line = voltage modulation?

Any advice is much appreciated.

Me and my aching eardrums thank you in advance,
Justin.

 

I'm not familiar with the back of an American mains socket, but have you got that probe clip on neutral or on earth?
Don't connect it to neutral, because it is connected to the chassis of the scope which is connected to earth.
The measurement between live and earth is interesting, as is the measurement between neutral and earth, but if you short neutral to earth with your probe it will upset the readings.

The jitter and moving peaks on the scope is just caused by it mistriggering, if you move the trigger up or down a bit it should become stable, you probably have it triggering on the interference. When it is stable, it should read 60Hz.
There certainly is some interference around the zero crossing in the first reading, but that's pretty normal for mains supplies.
Peak-to-peak voltage is 2√2 times the nominal supply voltage - that looks correct.

 

You will also find the video I took at dusk with the problem NOT being there

There is the first clue. There is something in your area that runs only during the day and is putting a lot of noise on the power line.

1. Is there something in your house that runs only and constantly in the daytime?

2. Is there any industry in the area that might have that?

3. Do neighbors on the same transformer also experience the noise.

4. What about neighbors not on the same transformer?

Loud (beyond normal) electronic buzzing sounds started to occur

This is the second clue. If you know when it started, what else was new in your area at that time?

No way we are going to diagnose it from an oscilloscope trace. But we can see that the sine wave is very bad. My sympathies.

 

I wonder if the noise is outside, and it just happens to excite an eigentone inside the building.
With a wavelength of 5.75m @ 60Hz the source of low frequency noise can sometimes be hard to track down. Does it vary at all with weather conditions and wind direction?
Have you tried using a microphone?
if the noise frequency is just a bit less than line frequency, then it is from a large induction motor.

 

I wonder if the noise is outside

Do you mean acoustic noise?

 

I'm not familiar with the back of an American mains socket, but have you got that probe clip on neutral or on earth?
Don't connect it to neutral, because it is connected to the chassis of the scope which is connected to earth.
The measurement between live and earth is interesting, as is the measurement between neutral and earth, but if you short neutral to earth with your probe it will upset the readings.

The jitter and moving peaks on the scope is just caused by it mistriggering, if you move the trigger up or down a bit it should become stable, you probably have it triggering on the interference. When it is stable, it should read 60Hz.
There certainly is some interference around the zero crossing in the first reading, but that's pretty normal for mains supplies.
Peak-to-peak voltage is 2√2 times the nominal supply voltage - that looks correct.

@Ian0 , there is clearly a jitter in the day video and not in the night video. The buzzing sounds like just about 60Hz jitter. So it seems during the day something is inducing that jitter into the mains and it stops at night?

@geong1 , Just some basic questions; how long has this buzzing been present? So if its there during the day and not at night, are there specific/set times that it appears and disappears, i.e. is there a timing pattern or any kind of pattern to it?
Have you tried any kind of mains filter on one device like your TV that you showed had a clear buzzing, to see if it stops it?

Do you live in any industrial area or are there any companies or factories near you that could be inducing interference on your mains maybe through heavy electrical machinery?

To me, it looks like interference is induced on the mains, especially if there is a clear day/night (period) timing pattern, FCC should be able to see that. Similar to back in the day when a hoover or hair dryer would put lines on the old TV!

 

Do you mean acoustic noise?

Yes.

 

Hi,
imho, you may try the following- take a DVM and measure mains voltage in DCV mode . I heard about such a problem from an audio fans. If a small DC voltage present in the mains, all toroidal transformers ( and, probably, other ) start to consume significal current.

And more. As BobTPH said- " But we can see that the sine wave is very bad "

 

Not that it will be of too much help but I will add my observations. This is the basis on which I would do my own investigation.

Based on the oscilloscope data, I would consider the diurnal nature the major salient point. So far as I know, it doesn't suggest any particular source, but it suggests that whatever is causing the problem runs in the daytime but not the night.

Wild speculation: do you have neighbors with grid tie PV (Photovoltaic) panels, that is a solar array? Does the noise track daylight, is it absent on cloudy days?

The noise looks a lot like the sort of thing I see from SMPS (Switching Mode Power Supplies)*, and I suspect that it could also be caused by an inverter of the sort used with PV systems. If the system is feeding back into the grid, you might be "enjoying" some green energy. (the sun is conventionally yellow, literally white, but they call it "green" so I am going by marketing patois)

Even if my Hail Mary suggestion is not correct, this diurnal nature, I believe, is the key to the problem and should be the guide in trying to locate it. There is nothing obvious (to me, and apparently to others) in the traces that would be a signature of the source, and the problem isn't something I've heard of before.

Another thing I would want to know, which might or might not assist in finding the source, it just what in your devices is transducing from electrical to acoustic. It is the inductors in the power supply? The transformers? Something else? Again, this might not be the solution but not only is it inherently interesting but you are reporting this as universal, which certainly is possible but I find surprising.

Along those lines, is there anything that doesn't do this that you expected to based in your understanding of the class of things that buzz?

One more thing, even if the source is never found, a solution might be. A filter targeting the noise could possibly be a solution. One thing that might be instructive in this regard is to use a microphone in a very quiet room to get a trace on the scope of the acoustical noise and see how it correlates to the line noise. You can use two channels and see them at the same time. I think that would be potentially instructive.

*An aside: I can recall a time when the 60Hz noise from touch a scope probe looked like relatively clean sine wave, not any more. It's some kind of incredible complex overlay of many signals now, I surmise from the large number of switchers all over the house.

 

The noise is at 160Hz which is not a harmonic of 60Hz.
The AC waveform shows the peaks clipping fairly badly maybe caused by very bright fluorescent lights?

 

The noise is at 160Hz which is not a harmonic of 60Hz.
The AC waveform shows the peaks clipping fairly badly maybe caused by very bright fluorescent lights?

Acordingto the data on the wave form scope display, the data on channel 1 is 59.99Hz, mains frequency. The flattening distortion is a type caused by either saturation of a magnetic core, or a diode going into conduction. There might be a transient protection device installed at the distribution panel that is a bit defective.

 

I thought @Audioguru again might have analysed the audio file with Audacity.

 

Yes, I simply sync'd my Audacity tone with the humming sound using my hearing to do the syncing.

 

Yes, I simply sync'd my Audacity tone with the humming sound using my hearing to do the syncing.

I thought I could hear another repetitive sound, and it sounded to me like a long belt going round a pulley.
160Hz could be a harmonic of something going on with an induction motor as it is 3 times 53.3Hz.

 

I believe that Ya’akov’s theory is very plausible: a solar grid-tied inverter which is malfunctioning.
I would survey the near neighborhood to see if any home has solar panels installed.

 

+1
Check if the buzz only happens when the sun comes up.
Check the neighbourhood for solar panels.

 

If a grid-tied inverter was not locked into the frequency it would likely destroy itself, or at least shut itself down.

 

If a grid-tied inverter was not locked into the frequency it would likely destroy itself, or at least shut itself down.

It might just be very noisy.

 

Really, you think it could operate continuously at 53Hz without blowing up? I find that unlikely.

 

Really, you think it could operate continuously at 53Hz without blowing up? I find that unlikely.

I don’t know that it is operating at 53Hz. You are combining two different, potentially incompatible speculative observations. I am basing my suggestion on the nature of the noise superimposed on the waveform, not on @Ian0‘s observation.

I didn’t make that clear, sorry.