Soft High Pitch Whine Heard From Power Brick: Cause of Concern?

Discussion in 'Sager and Clevo' started by darkarn, Jul 24, 2016.

Thread Status:
Not open for further replies.
  1. darkarn

    darkarn Notebook Evangelist

    Reputations:
    46
    Messages:
    655
    Likes Received:
    226
    Trophy Points:
    56
    Another strange query from me (lol): I heard some really soft high pitch whining from my power brick. I suspect it is there for quite some time (maybe since the beginning?), just that my ears have recovered recently (had temporary loss of hearing on my right ear)

    Is it something I should be worried about since I heard that such noises in desktop PSUs indicate an aging PSU?

    Thanks!
     
  2. t456

    t456 1977-09-05, 12:56:00 UTC Moderator

    Reputations:
    1,853
    Messages:
    2,514
    Likes Received:
    1,918
    Trophy Points:
    181
    That depends on whether the noise is caused by (coil) resonance or a leaking capacitor (these can also resonate). The former is harmless, but the latter can be problematic in the long run, presuming the adapter will be stressed. Finding out which it is is a bit difficult without opening it up, which in itself is a bit of a pain, too ... Chances are good it's merely resonance, since that's a rather common by-effect of using high-power components in very small packages, necessitated by a laptop adapter's small form-factor.

    Have a slim 120W adapter that made a high-pitched whine under load. It annoyed me somewhat, so opened it up and replaced the culprit with a higher rated model, solving the problem:

    [​IMG]

    Could buy a new adapter of course, but there's a chance that one too will be audible since resonance is not a technical malfunction per se, merely a by-product. Replacement parts are cheap, usually less than $1, so soldering is a nice solution even in case of leaking capacitors. Could also pad/embed the noisy component with silicone, which is exactly what that white goo is for (also silicone, non-coincidentally).
     
    ALLurGroceries likes this.
  3. darkarn

    darkarn Notebook Evangelist

    Reputations:
    46
    Messages:
    655
    Likes Received:
    226
    Trophy Points:
    56
    Wow, I didn't know there's two types of coil whine... And while I have soldered my own tube amp (and even fixed it), I am not sure if I am ready to open up the power brick to see it!

    Anyway, the whine is quite intermittent. Right now I have not heard anything. Yet.
     
  4. Meaker@Sager

    Meaker@Sager Company Representative

    Reputations:
    8,275
    Messages:
    52,263
    Likes Received:
    14,963
    Trophy Points:
    931
    Well one is coil whine, the other is a "singing" capacitor created by gases escaping the capacitor (this means it will dry out quickly).

    Most bricks do have a slight hum. You will find it varies by the load on the brick.
     
  5. darkarn

    darkarn Notebook Evangelist

    Reputations:
    46
    Messages:
    655
    Likes Received:
    226
    Trophy Points:
    56
    I hope it is just that slight hum...
     
  6. Support.2@XOTIC PC

    Support.2@XOTIC PC Company Representative

    Reputations:
    484
    Messages:
    3,148
    Likes Received:
    3,489
    Trophy Points:
    331
    It can be annoying but I wouldn't say it's something you need to be concerned about unless it's accompanied by some other problem. Many bricks have some sound, but few are audible above ambient room noise ,and fewer still are actually malfunctioning when they're making a noise.
     
  7. Ethrem

    Ethrem Notebook Prophet

    Reputations:
    1,404
    Messages:
    6,706
    Likes Received:
    4,735
    Trophy Points:
    431
    Quality has really gone down these days... It used to be that if anything had a whine you returned it and got another but now coil whine is everywhere so we are told to just accept it. I have two Clevo 330W bricks and neither have whine and my ancient 240W Dell brick doesn't either. It wouldn't be acceptable at all to me if they did.
     
  8. Meaker@Sager

    Meaker@Sager Company Representative

    Reputations:
    8,275
    Messages:
    52,263
    Likes Received:
    14,963
    Trophy Points:
    931
    It has always been there and many modern parts will not hum, but as frequencies increase this will become a harder and harder problem.
     
  9. Ethrem

    Ethrem Notebook Prophet

    Reputations:
    1,404
    Messages:
    6,706
    Likes Received:
    4,735
    Trophy Points:
    431
    Except we have been using the exact same A/C adapters for years. It's cheap manufacturing that's the issue in the case of power supplies.
     
  10. Meaker@Sager

    Meaker@Sager Company Representative

    Reputations:
    8,275
    Messages:
    52,263
    Likes Received:
    14,963
    Trophy Points:
    931
    As frequencies of the loads increases (eg switching speed of your cpu) the load profile on the brick changes. This can set up resonant harmonics in the power delivery and brick that will vary machine to machine. It's an incredibly complicated problem to deal with.

    I have opened some of these supplies and the caps are still the same high quality required for efficient delivery in a closed space.
     
Loading...
Thread Status:
Not open for further replies.

Share This Page