Cleaning a u87 Capsule

The Neumann u87, a revered microphone in professional studios, can sometimes exhibit an issue where it cuts out while you’re singing directly into it, but comes back to life when you stop. This problem tends to occur specifically during vocal recordings, while it typically performs well for other purposes.

Understanding the Cause

Condenser microphones, like the u87, rely on a charged diaphragm to capture sound. When this diaphragm accumulates dust and moisture, particularly from breath during close-up vocal work, it can lead to a temporary short circuit, causing the microphone to cut out. As the moisture evaporates, the diaphragm regains its charge, and the microphone resumes normal operation until the cycle repeats.

Addressing the Issue

Contrary to some online advice, diaphragm cleaning can be a safe and effective DIY procedure, provided the right approach is taken. Studio technicians regularly perform this maintenance, and with careful handling, you can achieve the same results at home.

Essential Equipment

  • Distilled water (ideally two small cups)
  • Two soft watercolour paintbrushes
  • Blotting paper cut into thin strips with rounded corners
  • Relaxing music (optional, but recommended for a calming environment)

The Cleaning Process

Preparation: Pour distilled water into two small cups, dedicating one brush to each. This ensures a clean initial wash followed by a final rinse with fresh water and brush.

Gentle Cleansing: Carefully swish the water over the diaphragm using the dedicated brush. Remember, the diaphragm is delicate, so avoid scrubbing or applying pressure. Gently move the water around to loosen and remove accumulated dust and moisture.

Targeted Cleaning: To facilitate efficient cleaning, tilt the capsule to clean the top half first. This allows the water and debris to flow downwards, where you can easily soak it up with the blotting paper or shake it off with a quick flick.

Thoroughness is Key: Rotate the capsule and repeat the cleaning process on all sides, paying particular attention to the clear ring around the edge of the diaphragm, where short circuits are most likely to occur.

Rinsing and Drying: Once the initial wash is complete, repeat the process with the second cup of clean water and brush to ensure a thorough rinse. Finally, place the capsule on a windowsill in direct sunlight to dry completely before reassembling the microphone.

By adopting this meticulous approach, you can effectively clean your Neumann u87 diaphragm without risking damage. Remember, patience and care are key when dealing with delicate equipment. With the issue resolved, you can get back to capturing clear, professional-grade vocals with your trusty u87.

Note: While DIY cleaning can be safe and effective, it’s important to acknowledge that some users might prefer to consult a qualified technician for this procedure. Ultimately, the choice rests with your comfort level and technical expertise.

13 thoughts on “Cleaning a u87 Capsule”

  1. Just saw your website looking how to properly store u87. I enjoyed instructions on capsule cleaning. I am currently in Boston MA area and would like to find someone who can look over u87 to make sure it’s in highest order to record with.

    Reply
  2. As Chris said, do not use anything than a brush.
    To clean it up, prepare 3 small recipients, with three different dilutions of deionized water and pure isopropyl alcohol.
    The proportions are: 1st: 25% isopropyl and 75 deionized water; 2nd: 10% isopropyl and 90% deionized water; and 3rd: 5% isopropyl and 95% deionized water.
    With EXTREME CARE, WHITHOUT APPLYING ALMOST PRESSURE OVER THE MIC CAPSULE, use the first solution alongside all surface. Léase it dry by itself. Yes, it is normal these kind of traces that you will see.
    When dries, apply with the same amount of care the second solution. Leave it dry it alone.
    And finally, once dryied, use the third solution. Once again, leave it dry by itself. DO NOT APPLY AIR OR ANY OTHER ACCELERATION!. OF COURSE, DO NOT BREATHE IT OVER!.

    You must repeat the procedure for the another side of the capsule.

    When you see you mic’s capsule clean and free of dirt and dust, you are done. Close your mic, and the capsule will perform as new again.

    Reply
  3. Possibly a stupid question.. Is it possible to get dirt UNDER the diaphragms? Looks like that is the problem with mine, like it’s sticking to the backplate. If it is.. what can I do?
    Thanks
    Danny

    Reply
  4. I tried to clean the capsule today of an AKG 414. Your instructions worked great! I just used an small blower that comes with DSLR lens cleaning kits to dry it almost immediately. Didn’t want to depend on some third party to clean it, this is the only website I found that gave clear instructions. Thank you!

    Reply
  5. I took all the shield away (quite easy – unscrew the bottom of the mic, take away the top part, in a delicate way) having a look on the youtube video “neumann how is done” and now i’m trying to clean it. Do you think I can use a normal cotton swab (same as the children one) and distilled water?

    Reply
  6. how do you get to the capsule? are there little screws… 20 year ago I send them to
    Gotham in NY… now they both cut out… the serial numbers are low, so they are old… I really want to try and clean them myself…

    Reply
  7. Hi,
    Thank for this beautiful direction. I tried this but still get some cut-out . Do you recommened any oil solution instead of water ? as the water seems not strong enough to clean the craps.

    Do I have to remove the screws around the capsule for better result?

    Kind regards,

    Javad

    Reply
    • No! Don’t use oil, and don’t unscrew anything. If water won’t shift the crud you should probably take the mic to hospital.

      Reply

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