Discussion in 'Reviews' started by crmaris, Dec 12, 2012.
To read this review go to: http://www.techpowerup.com/reviews/Corsair/AX860/
Well im kicking myself in the ass now hard for ordering my AX750 directly from Corsair despite the free color sleeved cable kit their offering. Newegg is having screaming deals on Corsair PSU's as I can get the brand new AX860 for $170 after 15% off promo code, free 3 day shipping and then $20 MIR! So thats a brand spanking new PSU model with even more power and efficiency for only $150 in the end!
Screw it, just placed an order for one and i'll see what the restocking fee is for this AX750 through Corsair or i'll sell it myself and regain most of the cost. Now I think 860 watts of platinum power should power anything I could throw at it for years to come no? I passed on the 860i model cause the Corsair software has not been getting good reviews from owners of the new AXi series and it just wasn't worth the $30 premium either IMO, I have no desire to monitor or change voltages on my PSU.
I refuse to buy anymore Corsair PSUs. Already have had three coil whining horrors now on my second coil whining AX750.
Despite a bit lower efficiency I am going for Super Flower Golden King Platinum 1000W. Just because it is so damn reliable and haven't seen a single coil whine case with it.
I have switched ALL hardware ALL softwarea nd even physical locations but no luck. Plug in any other brand PSU and there is no coil whine. Seasonic has lot of coil whining units too so I start to avoid them too.
has there actually been any evidence at all proving that coil whine is anything but annoying?
I too noticed coil whine at times, had a laptop that would whine a bit at times with a specific kind of load, but i never noticed anything bad coming of it except for the noise itself.
Is anyone here able to clarify this for me? (or provide some link to some research, I couldnt really find any good source myself).
It is just very annoying. Nothing dangerous about it.
For example it sounds like there is a bird in my PSU singing atm. Otherwise, the PSU works great.
the platforms of the new Seasonic and Flextronics based Corsairs carry many upgrades so most likely they fixed the coil whine problem that existed on some of the previous units. On all of my samples I didn't notice something anoying however coil whine depends in a significant degree on the rest of the hardware that is installed on the system.
How long do you usually test the units? Because usually the coil whine starts after some time, like weeks or month after use. That is why none of the reviewers ever notices it. After reading Corsair forum and youtube proof the new units are still having the same problem. Any idea what possibly could cause this kind of high propability coil whine problem on Corsair based PSUs?
I am all open for suggestions but I have really tried everything to fix the problem. Always Corsair or Seasonic based unit emitting electrical noises. Take any other brand PSU, even the low quality ones, and they have no problem.
I really want the AX1200i for many reasons but I don't want to get stuck in same kind of RMA loop that I send these units to the Netherlands (at my expense) and get unit back that will squeal again after month.
I was never impressed by the AX850, but the 860 is incredible, what the 850 should have been. Good job corsair, but now I really wanna buy it when I have no need for it, so screw you too
Actually you need to test it on various real systems to see if it does it and for prolonged time as you mention. Unfortunately I don't have the time neither the resources to do such tests (like all the rest reviewers).
But I have used several Seasonic PSUs in my systems in the past and I never noticed a coil whine issue. I don't know maybe I was lucky or the current systems didn't activate the coil whine issue but at least in my case I didn't notice anything strange.
I will forward this thread to SS and I am pretty sure that they will give some more input on this matter. Unfortunately I don't have a Flextronics contact to forward this topic, since you mentioned the AX1200i which is made by them and not Seasonic.
Coil whine usually doesn't affect either the PSU's or the components' operation, at least not to a measurable degree, since the resonant frequencies are typically such that they're easily damped in other components, such as capacitors and other filter coils. I believe all manufacturers are actually aware of this issue, and are doing what they can to deal with it, most of the time.
Namely, there are three ways coil whine will develop. There's "self-whine" to which every coil under the Sun is susceptible (including various types of transformers) by it's very nature, and there's resonant/induced whine, which is a byproduct of resonance between VRMs on the motherboard and/or the graphics card, and the PSU's coil(s) and/or transformer(s). Let me elaborate further:
As the current passes through a coil, it creates a magnetic field, which in turn induces a current in the coil such that it tends to cancel out the change in the initial current. So if there's a constant 1A through a coil, then it jumps to 1.1A, the change in magnetic field will induce a current of -0.1A (meaning 0.1A in the opposite direction), restoring the net flow to 1A. This is how coils remove unwanted ripple/noise from the DC output of a PSU, or a DC input into a VRM.
Both the length of the coiling wire and the coil loop diameter are parts of the inductance equation, and are a variable just like the inductance is, and not constants. Well, theoretically they are constants for a given coil when it's effective inductance is calculated, but in real world, where approximations amount to a wrong result, the coil will shrink and expand under the influence of magnetostriction.
Self-whine or coil noise can be twofold - physical and electrical.
Physically, high frequency switching used in PSUs (50-150 kHz) will make the coil vibrate (from all the rapidly succeeding shrinking and expanding) at a lesser frequency, typically from one quarter to one eight of the switching frequency. This is sometimes well inside the audible range (~20 Hz - ~20 kHz, typically 30 - 18k). The lower frequency vibrations are a consequence of the finite velocity of current (rather, electrons) and the finite speed of expansion/shrinkage propagation through the coil. Not only that, but both the wire and the core are shrinking/expanding, and at a different rate and amplitude, so until everything aligns properly (rate and speed of shape change with the rate of propagation of the deformations), there will be no audible vibrations. This is part of the story.
Electrically, as the coil loops are moving and the core changes shape, both travel inside a varying magnetic field, which causes additional self-induced currents to appear. These are mostly damped out by other filtering elements, due to their very low magnitude and their relatively high frequency, but sometimes they manage to get to an amplifier in a sound card, for example, and show up as audible noise in the sound (sub)system. Additionally, every coil is a (poor) antenna for high-frequency signals (voltage changes), and it radiates those signals out into wires and PCB traces. There they are induced back from electromagnetic emissions into current and possibly amplified as per above.
The kicker is that physical noise can (and does, in larger inductors) cause electrical noise, and vice-versa. Further, any wire or other form of conductor (like a PCB trace) is also an inductor, albeit a poor one.
Resonant whine can develop between any two oscillatory systems, which coils are all by themselves, as is practically any circuit that contains them. VRM circuits on motherboards, graphics cards, hard drives, etc. pretty much always contain at least one. In order to have an electrical oscillator, you need an inductor and a capacitor. All inductors are also (poor) capacitors, and this doesn't present a problem at low frequencies, because they "see" capacitors as open circuits. Self-capacitance is a problem at high frequencies, exactly the situations where you'd want to use coils in the first place... When two coupled coils (either connected via wires and traces or magnetically coupled, or when the EM radiation of one permeates the other) reach very similar electrical self-noise frequency, the parasitic signals they produce may be (and usually are) amplified exponentially. This can, in rare cases, actually pollute the DC input/output, and there are actual cases in practice. There are some Sirfa-made PSUs in which simply moving output wires away from a regulator coil makes the PSU output voltage significantly less noisy. I still consider this a rarity, though, and it can be solved by putting a simple EMI shield (a piece of isolated metal sheet) around the offending coil or between it and the "polluted" area.
Coil whine can be lessened to an acceptable degree with a relatively simple fix. Just dampen the physical side of it by gluing or caulking down the coil, so that it's vibrations are absorbed. Another way is changing the current/voltage frequency, which is never easy, as it affects the electrical design of the device in question, or use a different coil. This could be a coil made of different materials, or of a different size, or even a different shape. I've seen coils made in the shape of the number 8 (or the infinity sign, if you need to be geeky about it), that produce significantly less noise than standard toroidal coils. I can't say how much this would add to the price, however. And let's not forget that transformers are, in effect, simply big-ass coils, and their whiny nature is much harder to deal with...
As for why coil whine would develop in time, instead of right from the get-go, well... Perhaps the dampening glue/caulk "breaks in"? Or maybe the coils very slightly change their basic (at-rest) shape, such that their resonance pattern shifts into the audible range? Who knows, it's a very complex phenomenon.
Sorry about the wall of text. I just had nothing better to do. It might even help some
15% off on Newegg right now with another $20 off MIR. Tempted to pick one up before the sale ends. Even though it may not even be worth it to ditch my HX850, but i want fully modular so i can sleeve it individually without having to take the PSU apart to get the cables that are attached to the PSU internally. I actually like the AX860 more then the "i" version because of the San Ace fan.
but the AX860i is going to be less loud then the 860 on around 40~75% load right?
San Ace fan versus what?
The Yate Loon thats in the AX860i
I think ..
AXi - Flextronics, Non Japan Caps, Yate Loon, Software
AX - Seasonic, Japan Caps, Sanyo Denki/San Ace, No Software - winner for me
AXw - Flextronics, Full Japan best Caps, Software mora accurate, Sanyo Denki/San Ace, moddiy srinkless single sleeve cables
The caps do look better on the AX and the fan does look better too... I'd love an opinion of someone very familiar with the internals of a PSU about his opinion on which is better
If I need to choose in shop PSU for me I would choose AX750 or AX760 without i.
For sure. But Flextronics seems make better units these days than Seasonic, but difference is if you look everything 0.2% probably. That's stupid things... With such powerfull and excellent PSU's decide favorite brand, warranty, look of unit, cables, PRICE, what is available in shop.
I was ready to give some of quality for cables and look. Because difference is like 1866 vs 2133 memory and everything above Bronze can preserve hardware from damage...
I must be lucky, I've never had a coil whining PSU in about 14 years....I am anal about silent computers in general, especially fan noise so I can understand its pretty horrible if it happens to you. It would drive me nuts.
I dont think corsair are more prone to have it, corsair PSUs are more common than other brands and users are more likely to be enthusiasts who notice things like coil whine. Its weird the people that had a problem with coil whine, usually had it more than once on different PSUs. It certainly is a weird phenomenon.
Parden my PSU noobness, but can someone tell what all that white goop stuff is all over the place and why it looks so sloppy done?
Well the AXi version is digital which is completely different then analog (this PSU) in terms of the components internally. Digital is also better then analog.
That's glue or caulk, and it's used to additionally affix components to the PCB. There are two reasons for this: Firstly, it is good practice to take the stress of holding big, heavy components off the solder, to avoid having cracked joints. In the more extreme cases, some of the bigger components could even break off during transport. Secondly, and pertaining to the hijack subject of this thread, it is used to lessen the physical noise of some components.
It is less talked about and it's far less acute than coil whine, but some capacitors tend to squeal in a similar manner to the coils' whining. They're also much easier to dampen out, though. Gluing them down does the trick nicely.
Few moments ago I brought my new exemplar of AX860 to my home and connect it to PC. From the beginning of it's work I hear damn terrible coil whine. This noise killing my brain. I'm very sad. Going to change it on Enermax...
Just be aware that there is literally an equal chance that your new Enermax will also suffer from coil whine as well. This is not defending Corsair - it's a fact of life. No manufacturer can guarantee their PSU will not "chirp" because the phenomenon is not something they can ever hope to fully control.
Do you mean this is problem in single exemplar of AX860 and better for me to check another one? Because I'm really unhappy that so nice PSU got this minus with noise.
Yes, coil whine has been shown, time and again, that it varies from unit to unit, and that even PSUs from the same production batch can act differently. A specific unit may even be dead silent in one system, and chirp like crazy in another... If it's in any way convenient for you, RMA the unit. Most manufacturers (Corsair included) acknowledge coil whine as a legitimate malfunction, and will be happy to exchange your unit for a different one. It may help if you list your configuration specs in the RMA ticket.
Only that, my friend heard coil whine when teeth numb inside. That is high pitch sound like wire cross over rugged metal.
Nothing special only KGB torture people with high pitch noise, and nothing loud only that.
RMA them until they find cause of coil whine and way to stop that once for all.
That can be reason of anxiety and other similar symptoms if you sit close to source of high frequency sound.
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