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FIX: Neumann KMS 105

Inconsistent audio signal from your KMS105? The fix might be really simple. Here’s how I fixed one.

My wife Katie Nelson and I both use Neumann KMS 105 condenser microphones for live performance. We love how the microphones sound and trust the Neumann brand.

The Problem

Recently Katie’s microphone was passing audio inconsistently. Sometimes it was normal, sometimes the output volume was quieter, and sometimes it would crackle as if the XLR cable was bad.

I called Sennheiser, the parent company of Neumann, to inquire about repairs. They connected me directly with a bench technician who kindly asked questions about the symptoms and then walked me through the fix. He correctly suspected that the hex screws holding the capsule to the internal printed circuit board (PCB) were loose. In fact, the capsule was completely disconnected from the PCB. I was surprised that the microphone worked at all considering there was almost no contact between the capsule and PCB.

PRO TIP: Microphones work best when the capsule is physically connected. #signalflow

The Fix

  1. Take out the machine screw on the side of the microphone that holds the XLR insert in place. There may be a small lock washer underneath the screw. Set them aside.
  2. Unscrew the basket (or grille, as people often refer to it).
  3. Slide off the black capsule cover screen.
  4. Very carefully pull on the capsule while simultaneously pushing on the XLR insert. WARNING: BE VERY CAREFUL WITH THIS STEP. THE PCB HAS A SERIES OF WAVY CUTS IN IT. TOO MUCH PUSHING OR PULLING CAN BREAK THE PCB. GO SLOW. GO EASY.
  5. Pull back the rubber ring around the brass capsule body. Remember the orientation of the ring in reference to the notch in the body.
  6. Confirm that spring is seated properly on the capsule center pin.
  7. Push the capsule body onto the PCB until fully seated. The hex screws should be positioned over the solder-tinned holes.
  8. While holding the capsule and PCB together in that position, use a 0.035″ (0.89mm) hex key to tighten down the tiny set screws.
  9. Replace the rubber ring. Make sure the orientation of the ring fits into the notch in the body.
  10. Carefully insert the assembly back into the body. Again, be very careful. You will likely need small pliers/grips/etc. to pull the XLR insert all the way into position while simultaneously pushing the capsule into the body.
  11. Tighten the screw through the body into the XLR insert.
  12. Slide the capsule cover screen onto the capsule.
  13. Screw the basket onto the body.
  14. Test the microphone. If you still are experiencing audio problems, contact Sennheiser for service.
Little parts are easy to break. Be especially careful with this section.
Affiliate Links

Disclaimer: The links to the hex key and microphone above are Amazon affiliate codes. By clicking through and purchasing, I receive a small kick back. Thank you for your support.

5 Comments >

5 Comments

  1. 1 Zeljko Brodaric Jappa 7:53 am Feb 4, 2019

    Dear Mr Troyer, let me thank you very much for your detailed instructions for solving the same problems with my KMS 105 i.e. it had recently started to output an inconsistent signal. I had tested it by recording through it a 1 kHz sine for couple of hours and the recording showed an occasional abrubt as well as periodically gradual changes of level of considerable +- 15 db. Upon tightening the culprit screws (they had been completely loose!) I passed the mic though the same test and had a couple of hours of a consistent signal level recording! Fantastic! You saved me a lot of trouble having in mind that I live in Split, Croatia and that the nearest Neumann service is not around the corner! Thank you again!!!

  2. 2 Scott Troyer 8:01 am Feb 4, 2019

    Fantastic! So happy this helped you. Thanks for sharing your story.

  3. 3 Phil Miller 8:23 pm May 31, 2019

    Absolutely perfect. I had the same problem and didn’t see the allen screws at first. I couldn’t figure out how the board could get a solid connection. The screws were completely loose. THANK YOU so much.

  4. 4 Andy Le Vien 5:04 am Jun 1, 2019

    Would a drop of Loctite be ok on those Allen screws?

  5. 5 Scott Troyer 12:31 pm Jun 19, 2019

    Andy, I’m sure Sennheiser would frown on that, but it would probably work just fine.

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