Question Power Supply buzzing when connected to one circuit but not the other?

Aug 28, 2019
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Pre-knowledge: I am 20, still living with my parents so my ears may be able to hear higher frequencies. My power supply is a Corsair CX650M. I bought the unit from Micro Center.

My power supply has started to buzz somewhat loudly and consistently (bought and set up in January 2019. Issue started Today, August 28th, 2019) . I had removed my power supply from my computer to confirm this.

When I switch off the power supply via the switch on the back, the buzzing goes away entirely. When the computer is turned on the buzzing gets more dominant (I can stand about 8 feet away before I can't hear it anymore), and loading up Firefox (as a test, GPU has coil whine so running a video game drowns it out) might make it louder, but that could also be placebo.

I have 2 circuits in the room my PC is set up in, one on the North Wall and one on the South Wall. The North Wall circuit has this issue, I have checked multiple outlets to confirm this. When I connect my PSU to the South Wall (across the room from my setup) the buzzing gets quieter, to what I assume is normal functionality (lower pitch, only audible from <1 foot away when PSU is exposed/removed from case).

I brought both of my parents down to see if they could hear it, neither of them could. But to me the noise is enough to cause a mild headache after a while.

I have another PC with a lower wattage PSU (forgetting the brank, not Corsair) and it makes a small buzzing when the PSU is switched on with the computer off as well, but it can only be heard when I put my head next to the grill and while connected to the North Wall circuit.

My Xbox does not make this issue at all.

What should I do to go about this issue?
 

Wrecker75

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Pretty common actually, something on that circuit is causing interference. Had noise coming from one of my PSUs when I used an LED lamp on the same line.
 
Aug 28, 2019
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Pretty common actually, something on that circuit is causing interference. Had noise coming from one of my PSUs when I used an LED lamp on the same line.
Nothing else has changed on the circuit from the past couple of days though. I'm not sure why it would just start now with nothing new plugged in?
 

jonnyguru

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Nothing else has changed on the circuit from the past couple of days though. I'm not sure why it would just start now with nothing new plugged in?
Because someone, somewhere else in the house, plugged something into the same circuit that is feeding noise back into the line.

So... do you have a question or complaint or... ? I mean, is the buzzing keeping you up at night? Or, can you not keep the PC plugged into the South wall?
 

Wrecker75

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You mention bringing parents down to listen, is there something on that circuit on another floor in the house? TV, Fridge maybe even as little as a LED of florescent lamp. Also it could just be something in the power coming into the house, I have "dirty electric" not stealing power as that makes it sound but I live in a small old town and the quality is so poor that I can hear electrical noise in my ceiling fan from time to time.
 
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You mention bringing parents down to listen, is there something on that circuit on another floor in the house? TV, Fridge maybe even as little as a LED of florescent lamp. Also it could just be something in the power coming into the house, I have "dirty electric" not stealing power as that makes it sound but I live in a small old town and the quality is so poor that I can hear electrical noise in my ceiling fan from time to time.
My PC is set up in the basement of the house, which has separate circuits in the North and South walls. The basement circuits are also strictly in the basement (according to my father and the circuit breaker documentation), so nothing plugged upstairs should be affecting it. This just started recently so I just wanted to make sure it was not an issue with my power supply and could potentially damage my system if the issue gets worse.
You explain that it could be the power coming into the house, but wouldn't that widen the issue onto more than the 1 circuit?
I may just have to plug it into the South wall to stop the headaches, but that's not ideal as I would have to run an extension across the room.
 

Wrecker75

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The list of variables is a mile long, could be a change outside like a transformer, interference from something the line runs past, internals of the PSU becoming more sensitive to RFI after X amount of load cycles. It's kind of like a video card with coil whine, it makes you think something is wrong with it but you could have a the WORST coil whine and the card lasts a decade.
 

Karadjgne

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One of the most common ways you get interference is loose connections in either the neutral or ground somewhere in the path going back to the service. With all that, the most common place a neutral is loose is actually in the breaker panel.

Most service lines are aluminium not copper so crush relatively easily, especially after application of heat and vibration from electric usage.

Running through a panel and making sure every wire is snug hand tight is a good start, and service wires should be tight, then flexed to seat the wires, then tightened again.

Warning: unless you have a very good clue about working on electric circuitry and wiring, do not touch it. Get someone who does.
 

Wrecker75

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I've always been sensitive to electrical noise, I can hear a tv is on from another room even if its muted because they are on the phone if the house is quiet enough. Glad for LCD tvs, I can remember knowing someone was watching tv in the living room when I came home from school before I got the front door open I could hear that CRT. It's one of the reasons I built with PSU fan inside the case, to help isolate the noise, and since it another fan I count it into my airflow plans. My build is almost silent because I use either speakers or open back headphones so electrical noise becomes more of an issue.
 
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Good news, I found out what the issue was! I was browsing other threads that were similar and I came across one that talked about a dimmer switch. My parents are trying to get into the "smart lighting" crowd and recently started leaving the dimmer switch in the kitchen on. I walked up to it and noticed it too was making a buzzing sound, and switched it off. I came back down to my PC and the noise was gone! I'll have to tell them about the switch, which hopefully replacing fixes the issue. Thanks for JonnyGuru's and your help!

Edit: Missed Karadjgne, thanks for your input!

Edit 2: I can't figure out how to mark this as solved.
 
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Wrecker75

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"interference from something the line runs past"

Glad you found it, replacing with another of the same has a slim chance of stopping it, a different brand has a better chance, but if it can be changed back to a normal switch if the control can adjust it it may move the interference far enough away.
 

jonnyguru

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My parents are trying to get into the "smart lighting" crowd and recently started leaving the dimmer switch in the kitchen on.
Tell your parents they're doing it wrong. ;)

The dimmer switch works off PWM, not VA. So if the light fixture(s) max wattage exceeds the capability of the dimmer, even if the switch is dimmed, they're still overloading the dimmer switch. They need to either put lower wattage bulbs in the light fixture they are dimming or need a more robust dimmer switch.
 
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gn842a

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I thought a good psu was supposed to be able to screen out all different manner of interference? Mine has about twenty things it controls, not one of which I understand. Hard to believe a dimmer switch could be making the psu buzz. I mean, I believe it, but I haven't had something weird like that in about thirty years. I bought some kind of vaporizer thirty years ago that put out interference making TV and radio unusable. Greg N
 

jonnyguru

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I thought a good psu was supposed to be able to screen out all different manner of interference?
The PSU isn't affected by the line noise from the dimmer. It just amplifies the noise at an audible frequency from the PFC choke coil.

In other words: Nothing is "harmed" or "harmful". All magnetics vibrate. Whether or not they vibrate at an audible frequency depends on a lot of environmental variables.
 

Wrecker75

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I thought a good psu was supposed to be able to screen out all different manner of interference? Mine has about twenty things it controls, not one of which I understand. Hard to believe a dimmer switch could be making the psu buzz. I mean, I believe it, but I haven't had something weird like that in about thirty years. I bought some kind of vaporizer thirty years ago that put out interference making TV and radio unusable. Greg N
They are designed with better components that ignore most interference, but when you add in a variable like the above dimmer and smart lighting control likely made in China or Taiwan, they may have cut corners/used lower end components that would create the interference. If they can make more money and get by with a device that does what it says on the box without their company being known for selling things that start fires, they likely will. Plus as JonnyGuru mentioned they could have it set up wrong or not rated for how they are using things.
 
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Aug 28, 2019
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I thought a good psu was supposed to be able to screen out all different manner of interference? Mine has about twenty things it controls, not one of which I understand. Hard to believe a dimmer switch could be making the psu buzz. I mean, I believe it, but I haven't had something weird like that in about thirty years. I bought some kind of vaporizer thirty years ago that put out interference making TV and radio unusable. Greg N
It is also making the kitchen fan light flicker, I fiddled with it and at one point in the dim range the light nearly stays off.

Tell your parents they're doing it wrong. ;)

The dimmer switch works off PWM, not VA. So if the light fixture(s) max wattage exceeds the capability of the dimmer, even if the switch is dimmed, they're still overloading the dimmer switch. They need to either put lower wattage bulbs in the light fixture they are dimming or need a more robust dimmer switch.
It's an old switch so I'll get them to look into it
 

gn842a

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So the Corsair CX650M is pretty good but not "Corsair's finest" and that may be an issue? I was looking at it just now. Price wise in the $60 to $70 category, I thought that was pretty "safe." Is it possible then that a better psu would be more resistant to the interference?

And of course there's the chance that a $5.00 new dimmer switch will make the problem go away. Frankly main problem I see (round my house) is flicker from the LED lights (the ones that look and act like light bulbs, except when they start flickering).
 

Wrecker75

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It just comes down to the list of variables lining up to the point where it becomes audible from the components used. A better or properly set up dimmer could/should (or even different bulbs) eliminate the issue but at the same time while there is nothing actually wrong with the one he has, a PSU with different components might not react to it, not even necessarily a "better" one just different components, a cheap piece of junk PSU that uses inferior components might eliminate the audible noise, where at the same time you could pick up the house exactly as it sits and move it across town/state and the audible noise may change or be eliminated.
 
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jonnyguru

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So the Corsair CX650M is pretty good but not "Corsair's finest" and that may be an issue? I was looking at it just now. Price wise in the $60 to $70 category, I thought that was pretty "safe." Is it possible then that a better psu would be more resistant to the interference?
No.

Pretty sure that if a CX-M is making the noise that any Corsair PSU or 99% of the PSUs on the market will also make the noise as well.

It has nothing to do with the PSU's quality. Not sure why you're latching on to that.

Again: It's not "unsafe" to the PSU or your PC. It's just a noise.
 

Karadjgne

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They need a dimmer switch that has a neutral wire attached. A standard dimmer does not, just power in/load out. It works by lowering voltage. Leds have a ballast and require a certain amount of voltage to make it work right, or it buzzes. Dimmers with a neutral wire are (as Jonny said) PWM, so change the signal, not the voltage.

Don't be suckered by dimmers that say led compatible if you don't see a white wire.
 
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jonnyguru

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They need a dimmer switch that has a neutral wire attached. A standard dimmer does not, just power in/load out. It works by lowering voltage. Leds have a ballast and require a certain amount of voltage to make it work right, or it buzzes. Dimmers with a neutral wire are (as Jonny said) PWM, so change the signal, not the voltage.

Don't be suckered by dimmers that say led compatible if you don't see a white wire.
Honestly, I don't think they've made the type of dimmers that just lower the voltage in decades. LOL!

If OP's parents bought that type, they must have bought it at a flea market. :D

Even a "good" dimmer with PWM can make a buzz if it's just a cheap triac controlling the pulse. Better dimmers actually have a L-C filtering to smooth out the waveform and therefore no buzz.
 

Karadjgne

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Oh, I see all kinds of dimmers, even the old rotary rheostat kind, quite often. The problem is price. Ppl just don't want to pay for something like a Leviton Maestro series dimmer when the trusty old on/off toggle with the thumbnail slider is ¼ of the price. That works just fine for incandescent or halogen bulbs, but leds are a disaster. Even replacement bulbs will catch ppl off-guard, cheap 6pack of 60w equivalent is $18 and supposed to last 13 years or better, way better deal than $9 for 6 incandescent 60w that last 1-2 years.

I love flicker, it's like job security some days. Ppl get a handyman to replace all their incandescent with led, then call me when the house flickers like a blinking Christmas tree lol.
 
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