Coil whine with UDOO Bolt V8?

Discussion in 'UDOO BOLT' started by papa4narchia, Aug 28, 2019.

  1. papa4narchia

    papa4narchia New Member

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    I have significant coil whine with my UDOO Bolt V8. This occurs when it is being "switched off" and the whine modulates with the inbuilt orange LED pulsing (pitching higher when on and lower when the LED is off). The whining originates from the Bolt itself, not the power supply.

    Do you other Bolt V8 owners also suffer from this?
     
  2. ccs_hello

    ccs_hello UDOOer

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    UDOO Bolt (or any other SBC), when there is power present (even the PC is off), there will be a small amount current drain to get it into "ready to power on" state. In the case of BOLT, there must be a small DC-DC (say 12V to 3.3V) buck converter in operation. This type of switching regulators typically runs in the frequency range of 15 KHz all the way up to 100 KHz. I am not sure exactly the type used in BOLT, but I suspect the OP's hearing is extra sharp to be able to sensitive to the ultrasound range. View this as a blessing. I wish I can trade my long gone hearing with a dozen of BOLT :) :) , if there is such an "EASY" button to press.
     
  3. docofkult

    docofkult UDOOer

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    I can confirm that this is also something I have noticed. Not sure how much of a nuisance it is for me yet but it is definitely audible.
     
  4. itimpi

    itimpi UDOOer

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    I suspect that adding a suitable capacitor could help with this if only we knew where to add it :(
     
  5. Erkki

    Erkki UDOOer

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    Well, either I'm going deaf or my V8 doesn't have this issue, hopefully the latter as that would mean not all Bolts has the issue.
     
  6. nophead

    nophead UDOOer

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    My phone can hear a peak at 16860.5Hz when it is near the Bolt. It is a long time since I could hear frequencies that high.
     
  7. Erkki

    Erkki UDOOer

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    What software do you use for that ? I just tried using Spectroid (best rated free Android spectrum analyzer I could find) and saw no change i measuring next to the Bolt and 1 meter away.
     
  8. nophead

    nophead UDOOer

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    I used Spectrum Analyze free version. With Spectroid I see a peak at 16875.
     
  9. nophead

    nophead UDOOer

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    I am a lot closer than 1m though, more like 150mm.
     
  10. Erkki

    Erkki UDOOer

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    What I said was that I saw no difference between measuring right next (less than 5 cm away) to the yellow flashing Bolt and measuring 1 meter away. Had there been any significant noise from the Bolt the two measurements should have had significantly different results.
     
  11. docofkult

    docofkult UDOOer

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    Not sure where I read it but someone mentioned that the coil whine disappears if both the front USB ports are connected. I just gave it a try and it is does seem to fix the coil whine or at least reduces it significantly.
     
    Xeyrruken likes this.
  12. ccs_hello

    ccs_hello UDOOer

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    Yellow LED (power down state, USB-C powered) at 5 cm distance, my BOLT v1605B
    measured -86dB at 14.8KHz. (I can't hear it.)
     
  13. Xeyrruken

    Xeyrruken UDOOer

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    Yeah, mine is pretty noticeable, enough to drive me crazy while turned off, I have tinnitus and this noise I could hear it from one room to another, what I do is fully disconnect while Bolt is not in use.
     

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