Hi,

I've been looking for a quiet ~550W PSU for my i5 system. I want a nearly-inaudible fan and no electrical noise (whining, buzzing, squealing etc.), except at a close distance (< 1 meter). So far, I have tried four PSUs (Be Quiet! Dark Power, Be Quiet! Straight Power, Seasonic X-Series and Enermax Triathlor) -- all of them failed to deliver in the electrical noise department.

Perhaps surprisingly, the worst PSU was the Seasonic X-560 -- it was simply unbelievably loud under certain loads. I find it astonishing that it gets recommended for quiet systems. The Be Quiet Straight Power was the quietest of the three, but still too loud (buzzing).

I've described my adventures here:
In search of a quiet PSU

Best wishes,

Tomasz

Edit:
Added another PSU: Enermax Triathlor 550W.

Edit 2:
Added: BeQuiet! Pure Power 530W. This one looks like a winner.

While you're not alone in this, not everyone has this problem. There clearly is some sample variance, some people have even had 2 bad ones in a row. I would hope that with the Platinum rated models there may be some improvement.

As the problem was worsened when you plugged the monitor into the same AC circuit, it makes me think the problem is on the AC side and not the fault of the PSUs. Do you have any AC line conditioning, surge suppression, or UPS between the AC circuit and your PC? Do you have faith that the ground (or earthing) is good and that the AC wiring leading to this outlet is in good shape?

The outlet is not grounded. However, I don't think grounding should be necessary for quiet operation. The only thing the ground wire should be connected to is the computer's case, no?

Also note the interaction with the LCD display was present in only one of the PSUs - the Be Quiet Straight Power; four other PSUs were unaffected by the display... My Corsair HX520W is also inaudible in the exact same setup.

More likely, the reason is a combination of interference from the display and the PSU's (over)sensitivity.

Yeah, people always say "you just got a faulty unit". But I haven't read about a single case where someone RMA'd a PSU and got a replacement unit that was noise-free. Maybe the noise will get a bit softer, that's it...

I guess it's possible that the Platinum models are better; but they cost 50% more than the already expensive X-Series. After seeing "legendary Seasonic quality" with my own eyes (I'm not just talking about the coil whine, but also about the badly fitted plugs), it will be a long time before I buy another Seasonic.

Gut feel: higher efficiency designs are more sensitive to AC line condition. Try moving the PC to a location that does have a grounded outlet and see if the problem goes away.

That's asking for trouble. You don't list your location but whereabouts are you in the world? I would definitely never use a non-earthed supply for any computer equipment and having a power conditioner, UPS or anything else won't fix that problem. I have spent many years in the medical industry troubleshooting ECG equipment and electrical supply issues are something I have some experience with. Just imagine, your monitor and your computer are both connected to the same non-earthed supply and yet both internally need some 0V reference for DC volatges. Without an earth this is a problem so how they may achieve this is by floating it off the Live and Neutral. Different power supplies do this differently (this is especially a problem when Neutral is not well bonded to earth at the substation or a lot of induction has occurred along the line so you end up with a couple of volts on it by the socket) and you can end up with a small current between them along the Earth pin of the video cable for example. Opto-isolate the video cable by using a DVI over fibre optic kit and you might well resolve this but I can't help by feeling that you should use an earthed supply instead.

As for earthing a case, that's not a huge help for getting a clean earth. There's a lot of metal in between and some may be ferrimagnetic, some may be ferromagnetic, some may be non-magnetic and some even antiferromagnetic. That's all well and good for DC but for AC you really need to use a copper earth along the whole line to get a clean earth. What kind of resistance do you get back to earth?


Clearly the different PSUs are set up differently inside, they may float their earth differently. How you are running them without an earthed supply may be (or should be!) outside of the design spec.

Take a look at the Super Flower SF-550P14PE (Kingwin Lazer Platinum LZP-550 is sold in US and is same Super Flower unit).

Have a Seasonic X560 and it buzzes and whines, but gave another X 560 as a present and that one does not have coil noises unless close.

Just got the Super Flower unit and it only has the characteristics you defined as except at a close distance (< 1 meter).

Personally silence is paramount but haven't seen older PSUs with a very quiet fan(and/or silent). Used a HX520 before and it did not have that protuding coil noise, but the fan was audible. Super Flower seems to be the happy medium of crazy expensive and quite silent.
Edit: Super Flower unit has a little lower constant frequency noise in less decibel, than the X560 with high pitch frequency change, each time mouse is moved. It's easier to abstract from, but still not silent

i am going to have to jump on the poor AC band wagon here. try a grounded outlet (maybe even at another house or at work?).

also have you considered a quality UPS? Personally, i try and never plug in a computer in without a UPS in the mix ...

That's not going to help clean the supply I'm afraid, potentially it'll make things worse. The same for any kind of line conditioner. You shouldn't have to be using such a thing in a domestic environment (there's nothing THAT important) and if you are just because the electrics cut out too often, you should be contacting the power company.

This might be true for every building not older than 10-15 years in Europe, but if you happen to live somewhere in a house that has been build by someone 50 years ago, you'd be surprised how many things will go wrong because your electrical wires were installed without any solid knowledge about standards.

In some cases you only have two wires conducting 110 or 230 V... no PSU on this world can outplay bad cabling.

Very interesting discussion. Silence is paramount (well obviously on here) and with today's high performing platinum rated PSUs, with extremely stable and low ripple performance, I would expect this to be the next area to address for the Power Supply manufacturers, at least now with digital supplies (EVGA and Corsair) being available.

As for grounding a computer without ground in the wall outlet, would it not be possible to ground directly to e g a metal radiator?

While better than no earth, that is also bad. The plumbing and any metal structure of a building needs to be earthed but should not be used as the earth itself. Therefore you are not earthing it directly but indirectly. What happens if the plumbing happens to have a non-copper section of it somewhere along the line? Then you will have a poor quality earth. Radiators are also on a circuit so you have a massive earth loop created.

I know in some countries it is seen as passable to do this but it is far from perfect and really should not be pursued as a solution.

Interesting. Never thought of that. As for the material, I was under the impression that power cables are not copper either, or that they had to be for proper earthing. I live on the ground floor. Could I stick a copper stick in the ground and wire it to my PC?

They aren't always. Overhead power cables tend to be aluminium wherever you are simply because it is much lighter but also at such a high voltage that it matters less. Domestic wiring should be copper. The US went through a terrible phase where aluminium was used as being cheaper. This was a bad idea. In the UK we instead redefined how wiring was done to use ring circuits, the original reason being to reduce Britain's dependence on imported copper in the event of future conflict, a decision taken at the end of WW2 when much reconstruction was required.

An example of what happens when earthing is not entirely copper is the experience of a former colleague of mine in the US:
He'd moved house and was having lots of problems with fuses blowing, computers having faults, bad TV and radio reception, slow modem speed, all kinds of stuff really. He checked the wiring and found that the plumbing was being used as the earth. He then traced the copper piping and found in his basement that the water inlet passed through a galvanised tank. Just to test things he hooked a length of copper wire between the inlet and outlet copper pipes on the tank. The first he knew that anything was better was one of his sons shouting "Dad, what did you do?!? The TV reception is amazing!". Problem solved.

He then contacted a local building inspector to inform them of this seriously substandard installation, demonstrated the fault and was surprised at their response that that was in fact an acceptable way to build a house in the US.


Well, you could do as a suplemental earth but you would then have to ensure good continuity to earth, make sure it is wired up to standard and ideally make sure there is no connection between your supplemental earth and the existing earth. Better still, sort out the earth in the building. You simply shouldn't have unearthed sockets in this day and age.

According to OP blog's profile, he's in Poland, which if I'm not mistaken uses 230V AC.
Could it be that higher voltage AC causes more PSUs to buzz? Or maybe APFC PSUs are more likely to buzz?

Actually 220V. The standard across the EU is 230V +/- a certain amount which allows 220V and 240V in different countries.


If anything, the opposite would be more likely. Higher current would be more likely a problem than higher voltage.

Just a quick update:

I've tested another PSU: the Be Quiet! Pure Power L8 530W. Full writeup in my blog post, but here are the highlights:

- no electrical noise, except for a faint buzz when gaming (inaudible at > 1 m in a closed case)
- quiet fan with good profile (couldn't get it to spin up, even under load)
- fan is 120mm and probably a tiny bit louder than the quietest PSUs I tested, but still inaudible in my quiet system
- cheap (40% cheaper than Seasonic X-560)

In short, this PSU is a winner for me. It beats all the more expensive models from Be Quiet! and Seasonic X-Series. While it is slightly louder than my dead-silent Corsair HX 520W, in practice there is no difference between the two.

Another piece of evidence in support of my theory that the more "premium" a PSU, the more likely it is to buzz or whine...

Since my last post I finished building my new system(http://pcpartpicker.com/b/zgO) and I bought FSP Group AURUM 92+ Series PT-550M(http://www.newegg.com/Product/Product.a ... 6817104169). This is as "premium" as they get. So far I didn't hear any electrical noises in any situation I put it through: gaming, youtube, furmark, bitcoins, prime, 3dmark, idle.. My computer is sitting to the left of me, arm length away.

I'm not saying this is the best PSU there is since I have experience with only 1 unit, but...this is my experience.

Has anyone tried the Seasonic SS-520FL lately? The SPR review reported some coil whine that was fixed in the second model so I am wondering if any of the units in the retail chain still have the coil whine issue and if Seasonic would take it back if that is the case.

Also, FYI I found a clip of some reported coil whine on the X-660 here: https://www.youtube.com/watch?v=CH_N_B6bmbM

I have fixed a rather tough coil whine problem on my end. I use the HP Z600. Ea. time I turn off the PC, there is alow pitch hump, non stop, unless I pull the power cord off the PC, turn off makes no difference.

So we replace the power supply, in the end, a total of 3 times, and there is no difference. Finally HP said this is a motherboard bug issue. A newer ver. of the motherboard will fix this. And surprisingly, since a newer REV on the motherboard is installed, no more coil whine

Interestingly enough, at work my Dell desktop has the same problem. After Dell replaced mobo, everything was fine for 3-4 months and then it started doing that again.

Get the REV of that motherboard, call Dell for a new REV. (Revision) Dell & HP uses the same suppliers on power supply in China, they both use those hot plugable power supply. If there isn't a newer REV., you are entitle to get a newer model for replacement. Simply say that deg. of high pitch noise is unbearable

I know what to do. I'm the IT admin there. Next month I'll simply order a new computer. This one's warranty is almost up.

then you are in luck. I've done that w/ HP. I got a PC that for 2.5+ yr., they never fix a certain problem. Just a few mth. prior to warranty expire, that certain problem got worse. So because the PC is still under warranty and they can't fix it, I got a new PC -- newer model.

So I would be curious to know if dell will do the same thing, bylaw they should, as if they don't , it's a breach of contract law--your warranty, i.e. the service, is part of a contract when you buy the PC from them

How much was the Dell? My replacement HP is $6.6K

$6.6k?! Does it come with hookers and cocaine?!
I don't remember how much current one was. New one I'll config for like ~$1.5k, maybe even less. Don't know, haven't spec'ed it.
But this is offtopic for this thread.