Electronic noise from computer spread to power supply.

Discussion in 'General Electronics Chat' started by alan1975, Mar 5, 2012.

  1. alan1975

    Thread Starter Member

    Jan 1, 2012
    Hello ! Again!

    I have power supply, handcraft based on LMxx.
    I use this power supply to power all my electronic devices on my desk, so i have only one box plugged. I't save me about 10 normal small wall adaptors.

    Today i plug to this power supply docking station for my digital camera.
    5V 2A.

    Docking station work in this way:
    It have power supply for charge battery, and USB for downloading pictures.

    And... after plug i hear "brrrrrrrrrrr" in my digital audio headphones processor :/

    I run couple of tests, including connecting chassis (grounding) my computer, to NEGATIVE lead of my audio processor (using, external power supply) , and i hear that "brrrrrr".

    When i unplug USB cable from docking station , it stop that "brrrr".

    In my observation.
    That docking station, let noise from USB (computer chassis) go into power supply...
    Inside power supply my devices are connected in parallel. Of course every device have own fuse.

    I try add 0.1uF at output docking station, but not help.

    I think we wont fix that docking station (it's from my fuji digital cammera) i don't want break it.

    But maybe we can add some kind of filter between that station any my power supply to prevent sending (spread) that noise into other devices...

    If You need i can plug my MD into digital audio processor and record that noise.

    Any idea, how kill that ?

  2. nigelwright7557

    Senior Member

    May 10, 2008
    I havent seen problems with power supply noise on my PC.
    I use a USB mixer and there is no digital noise on the audio.

    Are you overloading the USB bus ?
  3. alan1975

    Thread Starter Member

    Jan 1, 2012
    No, i don't overload.
    Right now i have just plugged mouse.

    I don't have to plug tip of usb cable to get that noise.
    If i touch ground of usb tip (metal case) to chassis its send that brrrrr...