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Fix 1kHz noise on a USB microphone

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Fix 1kHz noise on a USB microphone, Replace power smoothing capacitor for a larger one: crwdns2935265:00crwdnd2935265:01crwdnd2935265:02crwdne2935265:0 Fix 1kHz noise on a USB microphone, Replace power smoothing capacitor for a larger one: crwdns2935265:00crwdnd2935265:02crwdnd2935265:02crwdne2935265:0
Replace power smoothing capacitor for a larger one
  • Disassemble the microphone as in the video by a fellow hardware hacker https://www.youtube.com/watch?v=DDfCjkH2...

  • The key is; heat the glue - the glue is very tough and rubbery and strong - unlike regular melt stick glue. Be careful to not heat too much the mount in the middle that holds the microphone capsule. Pry-off the top, heat the glue, squeeze in the side grille into a spiral so it can be pulled out the top.

  • Remove screws of the separation plate and pull the board out. Its held in again with the same glue in the rails.

  • Note the capacitor is much smaller than the pads were designed for. For reasons I assume is - cost saving - the factory decided not to use three size of capacitor but just two.

  • Remove the capacitor and replace it with just a bigger one, perhaps from a donor board. Don't worry about the value - it just needs to smooth out the power supply rail for the FET. Ripples in the current are introduced as the devices sends USB packets every 1ms (at 1 kHz). This capacitor smooths those ripples out noticeably.

  • Do not test the microphone outside of its housing as all you'll hear is your typical 50Hz noise from the electrical system.

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