Power Supply high pitch noise

pfmind · Post by **pfmind** » 20 Mar 2007, 15:50

Hi guys

Hopefully one of the resident experts here can help me with this question...

I'm sure some of you blessed (or plagued) with sensitive hearing can hear that high pitched noise that comes out of some PC power supplies or TV sets.

Any ideas as to what aspect of PSU (except for "being cheap"

) is causing this.

The HiPro 400W OEM PSU I recently got is making this noise when it is plugged in. With the mains connected to the PSU, I can hear a faint high pitched whine when I put my ear close the vent hole in the case.
The newegg comments about this PSU had a few others commenting on this noise, so I dont think it is becuase I have a lemon or a faulty PSU. It is brand new.

The PSU itself has Active Power Factor Correction, which is quite impressive to find on a cheapie OEM PSU I would think.
Could it be that active PFC PSUs, with their inductive/capacitive circuitry trying to increase the efficiency, are prone to this kind of noise.

I'd be keen to hear your experiences.

I'm particularly interested about the Aopen 450W, which I have confirmed is a Fortron FSP power supp, but has no PFC circuitry. Despite being older tech, would this still be a better PSU that the HiPro

BTW, just to clarify, I'm not talking about noisy fans or metal scrapping kind of sounds. The sound I am describing is definitely an electrical sound.
http://www.techspot.com/vb/topic2661.html

Thanks, cheers

Hman · Post by **Hman** » 20 Mar 2007, 15:55

Maybe it's your ears.

Dust · Post by **Dust** » 20 Mar 2007, 16:00

I know the exact sound you are talking about, my bud's TV does the same but he can't hear it. Don't know whats wrong with you PSU though.

pfmind · Post by **pfmind** » 20 Mar 2007, 16:15

@Hman

Well, that is reasonable assumption you make, but I tested that already...

The sound is not in my ears, because as soon as I unplug the PSU, after the 3-4 seconds it takes for the caps to discharge, the noise stops....so its not my ears or any other electronics I have in the room. There is an LED light on the Mobo (Asus P5B-VM) and that shows exactly when the charge has run out.

@Dust
I did a lot of searching on the web forums and it seems the "quality" PSUs like Antec etc are also sometimes prone to this kind of noise. I dont know if it is something that happens because of a certain design choice.

Thanks, cheers

lancelot · Post by **lancelot** » 20 Mar 2007, 16:40

It could well be a noisy fan whine, a little Q20 should do the trick.

viceroy · Post by **viceroy** » 20 Mar 2007, 16:48

pfmind wrote:@Dust
I did a lot of searching on the web forums and it seems the "quality" PSUs like Antec etc are also sometimes prone to this kind of noise. I dont know if it is something that happens because of a certain design choice.

Thanks, cheers

Where did you read this? I've never heard of "quality" PSU's being prone to this high pitched sound. I have an antec myself and not a sound from it except for a slight humming of the fan...and I'm very sensitive to these noises.

In previous job I forced the company to replace a workmates CRT because it made that kind of sound which would drive me mad on a daily basis

pfmind · Post by **pfmind** » 20 Mar 2007, 17:21

Hi

Its definitely not a PSU fan...like I said, just the PSU being plugged in with the PC still off causes this high pitched sound, most might not hear it...and when I unplug it, it stops after 4-5 seconds.

@viceroy: I read reports on various forums, I did a google search with "high pitch PSU noise" and it threw up a bunch of posts by people with various PSUs, ranging from cheap OEMs to decent ones by Antec etc.
extremesystem, hardware forum etc etc.

Some people say its caps in PSU, others say it is the inductor coils, some say it starts when the PSU is about to malfunction etc etc.
They noted that some TVs PSUs start doing this too.
The sound you describe from the CRT is also similar kind of sound.

I can use the PSU with the PC, its not like Mimi Coetzer singing...lol...but I guess I would prefer it if it wasnt there.
A reviewer on newegg said he had tested two of these PSUs outside of the case, on a testbed and both had this sound, so maybe this HiPro 400W model is built this way.

Anyway, if you guys havent experienced this, then thats good news.

Anybody have experiences with the Aopen 450W?

Cheers, thanks again

STIR · Post by **STIR** » 20 Mar 2007, 17:26

I know very little about computer psu's as an item, but In general, if a circuit has a dc to dc step up/down converter in it, which I believe some psu's do, it can create a high pitched ringing at certain loads.
You can check if its this by reducing or increasing the demand from the unit and see if it goes away or changes in pitch.

viceroy · Post by **viceroy** » 20 Mar 2007, 17:26

Anybody have experiences with the Aopen 450W?

not a bad PSU...nice on price too

Hman · Post by **Hman** » 20 Mar 2007, 17:50

I've got the 400W Aopen, Great stuff.

Bobendren · Post by **Bobendren** » 20 Mar 2007, 18:21

inductor coils

That's what i've read. Some motherboards have this problem too. I've sold a few AOpen's (as part of a full pc) and I didn't notice any whine.

Ike · Post by **Ike** » 20 Mar 2007, 18:37

I hear it too, On some cheaper tv's , old crt monitors, VERY old PSu's.

It may be the cheap electronics that's used, you can't fix it, if it's not broken...

goku · Post by **goku** » 20 Mar 2007, 20:48

My daughters psu does the exact same thing. it's a elcheapo power supply which I got with the case (her case can never be better looking than mine

).

The sound is random, one there and the next day gone. It also doesn't matter if it is under load or not.

RobThePyro · Post by **RobThePyro** » 21 Mar 2007, 10:06

What it is from is the high speed oscillations used by the psu to step up/step down the voltages, its generally caused by transformers which tend to oscillate at the frequency's that they produce. its not a bad thing if you hear that noise it just means all the circuitry is working well.

The reason different power supply's generate different sounds is really just based on the circuit design and how well the transformer is isolated (if there is one) tv's also do this because they usually have large flyback transformers to generate very high voltages for the electron gun. you can usually hear this noise in all electronics that are changing voltages, next time your charging your cellphone in a quiet room put you ear right next to the charger and you will probably hear the same high pitched noise.

WiK1d · Post by **WiK1d** » 21 Mar 2007, 10:17

RobThePyro wrote:cellphone in a quiet room put you ear right next to the charger and you will probably hear the same high pitched noise.

Yes, and that is pretty darn irritating

pfmind · Post by **pfmind** » 21 Mar 2007, 18:53

RobThePyro wrote:What it is from is the high speed oscillations used by the psu to step up/step down the voltages, its generally caused by transformers which tend to oscillate at the frequency's that they produce. its not a bad thing if you hear that noise it just means all the circuitry is working well.

Thanks Rob

So in your experience, have you come across this sound in the good power supply models like Antec, Enermax or Forton etc?

I'm thinking of getting the AOpen 450W as a replacement, which is a Fortron made PSU but without any active or passive PFC. Nice and cheap, hope it will do the job without this high pitch noise.

Thanks, Cheers

Stig · Post by **Stig** » 22 Mar 2007, 08:33

Yeah i am having that issue of a high pitched noise as well!! I have a AeroCool Zero dba 620w. The issue i have that this thing is about a week old and it makes this high pitched noise. I would not think a PSU at that level would make those sorts of noises.

pfmind · Post by **pfmind** » 23 Mar 2007, 20:11

Stiq, thanks for that info.

Maybe this noise is just normal, and most PSU's have it, even expensive models like your AeroCool Zero DB 620W, just that others dont hear the noise or dont really mind it.
Maybe they all have tinnitus from listening to their music too loud

I dont think it means the PSU is malfunctioning, so at least its not a very serious issue.

Thanks, cheers

pfmind · Post by **pfmind** » 23 Mar 2007, 22:57

For anyone interested to read a bit more on this :

http://techreport.com/forums/viewtopic.php?t=48797

EDIT : Interesting to note the power supps the guy tried are the most highly recommended ones from silentpcreview site.
http://www.silentpcreview.com/article699-page1.html

So I guess this confirms this isnt a cheapie/noisy power supp problem, some do it, others dont and most dont hear it

Cheers

PureFire · Post by **PureFire** » 26 Mar 2007, 13:10

my antec psu recently (dec/jan) started making this exact same high pitch noise... and i've had it for a year now. its working fine i suppose, but that noise is so damn irritating.