Considering how many Seasonic built PSUs are in the recommended list, and how common the coil buzz is in these models, I am dissapointed that in the (now) 4-page thread on this issue you only commented on the Zalman and Fortron-built PSUs.
This coil buzz issue is not trifling, since people - me included - pay more money on a Seasonic, instead of some other PSU, in order to get lower noise levels.
I believe Seasonic should address this issue (BTW, what exactly casues it could be investigated by SPCR), in order to fully deserve their good reputation.
What comment can we make if we've rarely encountered it ourselves?
It's true -- Seasonic-built PSUs are in use all over the lab in the systems we assemble, both the long term ones and numerous short-term builds for various testing (cases, etc). We just don't encounter it, at least nothing seriously audible enough to make us stop and reconsider our assessments.
We did report on some mild buzz in the HX620 review sample at <65W loads, but it was not enough for us to consider a serious noise breach.
To suggest that PSU buzzing is a Seasonic-specific problem seems unfair. It occurs in all kinds of power products from every brand. The SPCR audience hears and reports it more frequently simply because these PSUs are quiet enough for buzz to be audible, because we collectively build systems that are quiet enough for it to be audible, and because this audience is listening for it.
The number of pages this thread has grown to does not suggest any kind of "epidemic" like the NeoHE poll
(which went to 11 pages and 226 respondents). Remember, SPCR is visited by many many thousands of people who quietly take in the advice of the reviews, articles and forum discussions and make purchases without ever saying a word. Even 226 respondents is barely a drop in the bucket in the context of those numbers. If Corsair sold 3000 PSUs in the span of 9 mos (or whatever), how many would you expect to have some kind of problems? 1%? That's 30. Do we have 30 here? I don't think so. And if there is 1% that are anomalous, should this be considered a crucifiable sin? NOT!
I would suggest that to get some kind of handle on whether buzzing in Corsair PSUs is really as common as you seem to think, you start a poll modeled on the NeoHE poll, inviting ALL
Corsair PSU users to respond.
Capacitors and inductors are obvious components that buzz, but I've heard that even transistors and diodes can buzz as well. The cause is unlikely to be singular, as there always seems to be some level of interaction with components that the PSU is driving.