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I was wondering about this after two years of heavy coil whine from a pS4Pro power supply. It looks like the worst designed PSU ever made, and I'm aware some modern ATX PSUs have reduced coil whine to close to zero by using inductors.

What kind of inductors are these and how they are placed on the board I wonder?

ocrdu
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noiztmaker
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    You'd have to know ALOT more about the circuit in question and the nature of the components it uses. It's not as simple as "add this part, and the noise will stop". – Kyle B Jan 06 '21 at 00:52
  • The most assured way to make a transformer and/or coil *not whine* is to operate it above the audio frequency range. ie. above 21khz. – Aaron Jan 06 '21 at 00:55
  • @KyleB I think this might be more of a general question about how coil whine is reduced in systems, with the PS4 as an example where the noise is bad – BeB00 Jan 06 '21 at 00:55
  • The sound could be related to magnetorestriction – MarkU Jan 06 '21 at 01:54

1 Answers1

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It's probably not the type of inductors that has changed much over the last 10 years or so that has reduced whining, but the higher frequencies used now, well above the audio range.

Higher frequencies in switching power supplies allow for smaller components, using less PCB space, and the trend has been in that direction, despite possible higher switching losses. Making them "silent" is a happy side effect.

Also, reducing inductor noise isn't a design criterium for all manufacturers; perhaps some do this better than others.

Apart from that, some physical form factors of inductors do whine more than others, and their mounting plays a role as well. I don't know if there are Special Super Silenttm inductors out there, though; I never noticed any advertised like that in suppliers' catalogues.

BTW if it really is driving you crazy, try applying a dab of glue or nail polish to the inductor in a few places and let dry; it tends to silence them.

Note that capacitors can also make a sound all on their own, especially ceramic ones (piezo-electric effect), so the inductor (magnetic field, magnetostriction) isn't necessarily the (only) source of the whine. You can read more about that here: What might be the cause of high pitch sound coming from a switching regulator circuit?

ocrdu
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  • I'm not going to change the PSU components but I wonder if the inductor is the solution or replacing the main capacitor. I heard conflicting answers about capacitors that could cause loud coil whine (transferring to the CPU/GPU chip for instance) – noiztmaker Jan 06 '21 at 08:37
  • I may have misinterpreted your question then. Yes, capacitors can make a sound all on their own, especially ceramic ones (piezo-electric effect), so the inductor (magnetic field, magnetostriction) isn't necessarily the source of the whine. You can read more about that [here](https://electronics.stackexchange.com/questions/34806/what-might-be-the-cause-of-high-pitch-sound-coming-from-a-switching-regulator-ci) and in other places now that you have the proper Google terms. – ocrdu Jan 06 '21 at 11:32
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    Thank you! :) appreciated – noiztmaker Jan 07 '21 at 12:07