I have been using this fanless PSU for nearing one month. It's almost silent in 90% time, i.e. only if I place my ear very close (<10cm) to it, I can hear a faint buzz. However, occasionally the buzz noise of this PSU can become very significant, which is clearly perceivable from 50cm far. It's difficult to describe how "loud" it is objectively. But comparing with my other noise sources (2 low speed fans and GreenPower disk), it can be the dominate noise of my system, at least louder than the 800rpm Noctua case fan. Therefore, I think it's abnormal and somewhat unacceptable for a "fanless" PSU. Some more information related with this issue:
1 It happens occasionally, perhaps once every 3~5 days. When it happens, the duration is random, sometime it can be a few minutes, while it can be as long as more than one hour.
2 It's not directly related with load. Last time it happens during system idle, then I run Prime95 to burn CPU, and bump the AC power from 65W to 115W. There is no any change in buzz noise. Then I shut down the system, the buzz noise is still there and almost the same I guess.
3 It's not directly related with temperature. I encountered this issue in 2nd day when I use it, the temperature is 25C in my bedroom. Today I met it again, and the temperature is reduced to 15C now.
4 I tried to change the socket and cord, close all other electrics such like HDTV and air container when it happens, no any help.

I have no idea of how to debug this issue next (though it's still tolerable), have you encountered similar problem (especially Seasonic X series users) or could you share some experience?

The "randomness" of the noise reminds me of the buzzing of my hi-fi amp, where I think the transformer is the (main) source of the buzzing.

Sorry I don't have any recommendations, short of checking if something is loose and vibrating.. but in any way it's bad that it buzzes audibly and you should be entitled to a replacement under warranty when/if you decide so.

If it's intermittent and duration is random, it might be due to variations in AC quality on the electrical grid?

Are you sure it's the PSU and not something else? Have you tried a different PSU to see if it happens at all there as well? I had a motherboard at the office that did this. It was random as for when it would happen and then it would eventually go away. Sounds similar to your problem. That motherboard eventually died with caps that were bulging.

I'm sure the noise is from PSU instead of motherboard. When the problem happens, I plug out all fans in the system, thus there is only one hard disk left. And I can confirm the noise is from the region of PSU.

Besides PSU itself, I also hesitate whether it's possible with the electric grid. My home generally has a slightly higher voltage (~230V instead of the local standard 220V), I will monitor for some time to see whether there is any relationship between the noise and voltage, as ermi mentioned the buzz noise may be from the transformer.

Hi netmask254,

Did you had your bussing noise problem solved ?

Not yet, I sent a mail describing this problem to Seasonic support. They ask me to contact the distributor to replace one sample and check whether it still happens. It may be either a design issue or my apartment's electric issue. However, I didn't get time to try it yet.

Anyone else having this buzzing noise? I'm thinking of buying this model, but concerned about buzz as stated by OP

I have an X-460 and it too buzzes. But I can only hear it if I stick my ear right next to it. I can't hear it normally.

I have tried 2 Seasonic X-460W fanless power supplies, and both of them make buzzing sounds.

The buzz becomes a high pitch constant squeal when the computer is turned off, but has the electricity cable still plugged into the power supply.

It's extremely annoying and disappointing. I had no problems returning the 2 power supplies and getting my money back, as they are supposed to be dead silent.

When will we see TRUE dead silent PSUs on the market? I've been waiting for years. How hard can it be, to make something really silent?

I believe every PSU has buzz noise (there is no zero dB product), even my X61S' 65W AC-DC adapter can emit buzz noise sometimes. However, if you leave it several centimeters away and can't perceive the buzz noise, that's fine enough. I suppose you need to adjust your expectation

Seasonic has similar design for all X series PSU. You may try some Enermax Golden model, though it has slight fan noise, it MAY have different buzz noise with Seasonic.

I've heard some x-650 has the same issue,

Maybe it's your house electrical Systems, try it elsewhere and see if it solve the problem

I tried 3 X-650s, all have same buzzing noise as the X-460s. Returned them all.
I think all of Seasonic's power supplies have this problem. How disappointing.
It's not a problem with my electricity, because I experienced the same noise in 5 different locations, including the shops that tested them.

Just got the x-400 and it too buzzes, it is only audible from 20 centimeters or so, but it drives me crazy, even when sitting further away I seem to hear it, although it is probably imagination or tinnitus. After much research it seems they all have it, but most people just can't perceive it, like with those dog whistles.
After more research I read that turning off the energy saving functions of the CPU in the BIOS can cause it, and it did lower the buzz, now it is quieter...
What weird is that it starts to buzz as soon as the power is plugged in, and even about 5 seconds after you pull the plug. It actually becomes a bit less after the BIOS is done loading.
I could return it, but if they all have it...and after I get my money back, I am worse off even with louder PSUs.

(I can judge the sound accurately because I have switches for all case fans, cpu and gpu passive cooled and no drives connected other than a SSD. And when stopping the fan of the previous PSU, there was no buzz.)

I own a Seasonic X-560 and it whines all the time. Sure, I can't hear the fan, but the electrical whine is loud enough for me to constantly hear it while I sit at my desk. When the computer is in sleep mode, the PSU starts to whistle different pitches. Very annoying and I am not sure what to do.

This is a real, documented issue for lots of electronic power equipment. Not just Seasonic PSUs, and not just computer PSUs. AC power in many places in the world are subject to a host of variations:
- voltage (up/down by 10% or even more)
- frequency (up/down, not stable)
- distortion in the waveform: This could be the most common culprit. It can be caused not only by the electrical utility but also by feedback/noise introduced back into the AC line by poorly designed gear drawing from the same power box (like in a condo or apartment building).

Over the years, I have had discussions with SPCR writers and forum members in NYC, LA, and other parts of the US about issues with AC power quality & consistency. I am sure it happens elsewhere in the world.

I suggest you monitor the time of day that the buzzing occurs, over several days or even a week. The fact that many of you are reporting the noise even when the PC is powered down suggests an AC line issue. It's not clear whether the Seasonic X models are particularly susceptible in this regard or whether they allow the PC to run quietly enough without the masking effect of a fan that the buzzing is more clearly audible.

Those who have access to an oscilloscope or any kind of AC power analyzer should try monitoring the AC waveform when the noise is occurring badly. (Naturally, you better be careful and know what you are doing, as AC power can kill you.) Finally, it might be worthwhile to try different types of line conditioners or filters to see if they can reduce the buzzing.

For what it's worth, the very first pre-production X400 sample I received suffers from a bit of buzzing, but it's low enough that when mounted in a PC with any fans in it, the noise is rarely audible. All the other X series samples buzz too little to be consider audible... and there is a good half dozen X series PSUs at work in the lab.

Keep in mind that Vancouver has excellent AC quality, and the electric service box in this house is generally very good. I have heard the effects of AC waveform distortion in some gear here from time to time, though -- audio amps with large transformers in them sometimes get buzzier at peak demand times -- evenings. I can't recall any PC power gear with such buzzing variance, though.

Rather than try to blame it on the quality of the electricity, why doesn't Seasonic just spend a few extra dollars to make sure that every part in the PSU is solid and doesn't make buzzing/squealing/whining noises?

I have some generic brand PSUs that don't make anywhere near as much buzzing noise as the Seasonics. So it is definitely a problem that Seasonic can fix, if it puts its mind to it.

It's definitely worth Seasonic looking into, I bet a lot of their power supplies are being returned because they buzz. They could save thousands of dollars by making them completely buzz-free.

It's me that's suggesting electricity quality is a problem, not Seasonic. And I did not suggest it's the only problem.

Sure. And what is their efficiency? Quality? And overall noise level?

And I bet the same is true for every super-quiet PSU maker. If it was so easy to fix, it would have been done already... and I would never have heard buzzing from any electronics.

Would connection to a UPS make any difference?

People fix it at home with plastic spray, so how hard can it be to properly attach the coil kernels to prevent vibration?
No, I am thinking they are just not aware of the problem since many people do not notice the sound at all.

Hi,
I have the same x-400 issue. It's a high pitch whine when the computer is off but still plugged it.

I read a comment on a forum about seasonic buzz that might have a fix;

http://forums.hardwarezone.com.sg/showp ... stcount=37

I've just ordered a good new extension with EMI/RFI filtering.

I have a unexpected update, since I switched my mainboard,cpu und ram (to asrock z68 pro 3,2500k and 2x4GB g.skill 1.25v,internal graphics) I have no more buzzing in idle at 28w. Only when playing games above 50 watt I can hear the faintest of faint buzz when pressing my ear on the rear of the PSU. Also no more strange noises after turning the PC off. I am happy.

EDIT: now that I read the link in the post above me I also switched the cable extension from cheap belkined-in-china to expensive made in germany brennenstuhl, maybe that really helps with buzz? Gotta do more testing...

More info on the "fix" please... is it because of the surge protector, or the motherboard, that solved the buzzing? What brand is the surge protector? Is Belkin good enough or not? So many questions...

I have tried a few surge protectors before, not the expensive ones though, they made 0 difference to the buzzing noise.

It is probably not the surge protector, I just plugged the computer directly into the wall and no buzzing either. But I am not going to try the belkin one again, it gave me sparks the last time I had something in it, so I am afraid of it. The new expensive one is Brennenstuhl Premium protect line, it is actually made in germany, not china, I was surprised that it still possible. It is massive in size and weight, extremely solid, I love it. Cost me 30 euro, which is 45$.

http://www.brennenstuhl.de/content.php? ... tails=1588

So it might have either been the old motherboard, or the lack of a discrete graphics card. That is all I changed apart from RAM.

Thanks for the info. It is the motherboard then. Both the motherboard and the PSU are at fault (because the PSU shouldn't buzz under any circumstances), but it looks like it's possible to avoid the buzzing if the motherboard plays nice.

I'm going to do a big upgrade to my pc, picking Asus P8Z68-V Pro, i5-2500k and 4GB Corsair Vengeance, Crucial SSD M4, the GPU is already passive; i'm going to change the PSU too, and i want the most silent one like the X-460 Fanless.
My only thought is this buzz problem, will i get it with the Asus motherboard?
Maybe someone who got bot the X-400/X-460 and the Asus P8Z68-V Pro can answer my question?

On the AnandTech Review they said that this PSU is really dead silent, but it's better to know from real members in this cases i think.

fwiw, I had the high-pitched noise experience with an Antec PSU nearly a decade ago. Chalked it up to a noisy capacitor, since it responded exactly as one poster described above, where it would be a faint noise even when PSU was off and it even lasted a couple seconds after power cable was removed.

The noise was more perceptible when turning my head at certain angles (I've found this to be true of all random high-pitched noise from HDDs, motherboards, etc), so things that can help the most are re-orientating the case in its current location and also moving it further away from you (down to the floor if possible, putting a desk or other objects between you and the case's exhaust side).

I currently have a Corsair HX650 that is dead silent sitting about 2-3 feet (~1 meter) from my head right on top of my table and it is almost directly facing me.

Any updates on how to avoid getting a buzzing X-460 unit??

I just bought an X-400 (my old Antec Phantom finally died), and it is completely silent at both idle and load (about 180W). And doesn't even get warm.

I'm using an x-400 in my HTPC, and it's completely dead silent. No buzz, whine or anything even when i stick my ear 1cm from the psu. Since it's located among my livingroom media equipment it's also behind a Monster surge protector/power conditioner.