fifo Posted June 9, 2014 Share Posted June 9, 2014 I received a replacement ax760i which is producing a high pitched whistle sound even when the pc is off. Infact the sound seems more dominant and loud when the pc is off. I can probably live with it when the pc is on but not when its off as it is louder. On the plus side the buzzing (like transformer) sound that I was getting on my ax760 (sea sonic) is no longer there with this i version. Just this high pitched whistle infact when I turn off the power from the mains the sound is there for a few seconds then dies down. This implies to me thar this must be emanating from a capacitor. I have read a review of a person who had the same problem with the ax760i. Thus I want to find out if anyone else is having similar problems and If I get the unit replaced what is the likelihood that I will have the same problem again. Besides this issue I really like the ax760i the fan seems quite even at startup and only ramps up for about 2seconds at startup even then its quite with a slightly whisper sound at low speeds. Thus I don't understand these reviews that say its loud and sounds like a hairdryer. Seems pretty quiet to me. Link to comment Share on other sites More sharing options...
JKeifer Posted June 9, 2014 Share Posted June 9, 2014 Hi fifo. That's very unfortunate that you traded one noise for another when you RMA'd your supply. One could only speculate whether or not another RMA would result in a completely noiseless replacement but I'd certainly give it a try as chances are it would be a good one. Possibly contacting customer support directly over the phone would facilitate closing your issue to your ultimate satisfaction. Good luck! Link to comment Share on other sites More sharing options...
fifo Posted June 9, 2014 Author Share Posted June 9, 2014 The strange thing is that this is the first psu i've had that produces a high pitched sound when the pc is off. I've had an ax750, an ax760 and an ordinary 400 w case psu, NONE of these psu's ever produced a high pitched sound when the pc was off. Why axi? Link to comment Share on other sites More sharing options...
JKeifer Posted June 12, 2014 Share Posted June 12, 2014 I don't think any guess I could make as to why your PS is whistling at you would be satisfactory. I hope you have a uneventful RMA process or otherwise have it replaced to your satisfaction. Link to comment Share on other sites More sharing options...
Corsair Employees jonnyguru Posted June 12, 2014 Corsair Employees Share Posted June 12, 2014 If the PSU makes noise when it's off, it's coming from the +5VSB circuit. Once the PC is on, the load on the +5VSB switches over to the main +5V rail, which is a completely different circuit. Link to comment Share on other sites More sharing options...
fifo Posted June 23, 2014 Author Share Posted June 23, 2014 Right i had the psu replaced, i also bought another Axi760 to test. Now the replacement axi was better than the first one, the high pitch sound when the pc if off was quieter when i put my ear near the psu about 20 cm away though i could still hear it slightly and there was no high ptch sound when the pc was turned on unlike the first psu. The axi 760 i purchased was even better than this replacement you can only hear the high pitch sound when the pc is off when you put your ear next to the psu (with the psu ouside the case) you can' t hear it 30 - 40cm away and when pc is ON you can't hear it at all. Hence to sum up i have tested 3 axi 760 psus with my Gigabyte socket 775 GA-ep45-UD3LR - with only the motherboard, psu, ram and Wifi card connected (no graphics card or drives) First PSU - Noticeable high pitched sound When Off, lower High pitched sound when on Second PSU- Lower high pitched sound when off. NO high pitched sound when on. Third PSU - Even Lower High pitched sound when off , NO high pitched sound when off. Thus after trying 3 psu's it seems like this third one is the best i'm going to get. It seems like the high pitched sound when off can not be totally eradicated, you always have some amount of high pitched sound which you can hear if you put your ear next to the psu. Each psu seems to have a different level of high pitched sound. Some have high noticeable levels and some have a lower less noticeable levels of sound. Tell me if i'm wrong but i thing its due to the high effiiency/High power rating of the psu's that makes them whine. As the stand 400W psus do not seems to have noise problems. Link to comment Share on other sites More sharing options...
Corsair Employees jonnyguru Posted June 23, 2014 Corsair Employees Share Posted June 23, 2014 You are correct. The whining issue has always existed in the market, but not since the ErP2013 standby efficiency standards did we start seeing "chronic" whining noises. ALL components do vibrate at a particular frequency, but that frequency is typically outside of human hearing. Unfortunately, some components drop below that threshold of audibility and some peoples' hearing is better than others. Link to comment Share on other sites More sharing options...
fifo Posted June 23, 2014 Author Share Posted June 23, 2014 Thanks for the reply, I thought the frequency at which the components ie coils vibrate depend on the switching frequency thus if the switching frequency is greater than 20khz the coil noise would be greater than 20 khz if the frequency is 50 hz then you get mains hum. I take it the erp standard makes the motherboard consume less power when the pc is off, hence the psu has to source ea lot less power when the pc is off which increases coil noise. Why does low load increase coil whine? From what I have heard it also varies from mb to mb I assume this is because some mbs consume less power. Have you come across an ax760i that does not have any high pitch sounds coming from it when you put your ear next to it when the pc is off ? I have tried 3 and have not come across one with zero noise when I put my ear next to it and pc is off. I plan to buy a new mb (gigabyte z97x-ud5-black ) which are said to be one of the best mb and have gone through rigorous testing. Just hope psu noise don, t increase whith it. My current mb is 5 years old and does not have erp. Link to comment Share on other sites More sharing options...
Corsair Employees jonnyguru Posted June 23, 2014 Corsair Employees Share Posted June 23, 2014 Only the transformers are increasing harmonic frequency with the increase of switching frequency. And it's not that "low loads increase coil whine". Again, when the PSU is in standby, only the +5VSB circuit is live. That is where you're getting your noise. It's not a matter of low load vs. higher load. It's a matter of a load on the +5VSB circuit versus no load on the +5VSB. And it doesn't matter what your motherboard is. ErP2013 is a standby efficiency standard. That means the PSU has to be a certain efficiency when the PC, regardless of motherboard, is in standby. Link to comment Share on other sites More sharing options...
fifo Posted June 24, 2014 Author Share Posted June 24, 2014 The switching frequency must be greater than 20 khz as the transformers are silent. When you say coil i'm assuming you mean an inductor which is used for smoothing the supply. Am i correct. If so then the frequency of the ripple must be making it whine, but if the frequency is greater than 20 khz it must be hitting the coils natural frequency of vibration which is producing the sound. I think i am getting confused with the Erp modes (on/off) that most of the new motherboards have which you set in the BIOS. Mine didn't have erp mode as it was 5 years old. I have read certain posts asking customers to disable erp in the BIOS to get rid of the coil whine. The erp mode makes the mb consume less power < 1W on standby. I think the Erp 2013 your tailking about applies to psus. So it is the small standby load that uses the +5VSB circuit in the psu which is why it whines when it is in standby. The seasonic based AX760 unit i had was buzzing when the PC was actually turned on and went a way when the pc was off. Different symptoms than the AXi 760, where you get no whine at all when the pc is on, and some whine when the pc is off. Link to comment Share on other sites More sharing options...
Corsair Employees jonnyguru Posted June 24, 2014 Corsair Employees Share Posted June 24, 2014 Sorry. When I say "coil" I mean any of the megnetics. "Coil whine" is a generic term used on the internet for a PSU that makes a whining noise, whether it comes from a coil, transformer, film capacitor, etc. And you are confused about ErP. ErP is a whole range of European requirements. Lot 6, specifically, is a requirement that all power supplies are a certain efficiency while in standby. Like I've already said, this has nothing to do with your motherboard. You could have no motherboard. You could be powering a squirrel cage fan. It doesn't matter. It is the PSU that is either ErP Lot 6 or not. Maybe you're thinking of C6 sleep states, which isn't an ErP thing. That's an Intel thing. Link to comment Share on other sites More sharing options...
fifo Posted July 4, 2014 Author Share Posted July 4, 2014 You were right about the +5vsb I tried another motherboard And still got the slight whing noise I got with the previous motherboard when the pc was off. So if were to connect a 3 pin fan via the molex connector to the psu will their still be load on the +5vsb circuit to produce the same coil whine it produced with motherboard connected and the pc off? I noticed that when the psu is actually on and the mb is turned on, when the mains switch is turned off you get some coil whine which is a bit louder for about 2 seconds and then dies away. I have seen this on two psu's. Not a big issue as it is 2 seconds just wondering why that happens despite virtually no coil whine during pc off and on, just when the mains switch is flicked to off for 2 seconds. Link to comment Share on other sites More sharing options...
Corsair Employees jonnyguru Posted July 5, 2014 Corsair Employees Share Posted July 5, 2014 No. The only load on the +5VSB is through the single +5VSB wire that runs to the motherboard via the 24-pin connector. Link to comment Share on other sites More sharing options...
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