MXL 990 Microphone Mod / Rebuild

(2 customer reviews)


Choices for Stock or Improved Headbasket

Instructions for shipping your mic to us will be provided after checkout

  • Options Price: $0.00
  • Product Price: $239.00
  • Total: $0.00
SKU: 990u Category:


This is a Mod /  Rebuild of your microphone.

This is one of our most effective MXL 990 Mods. The standard MXL mass-produced circuit board is replaced with our all discrete jaSb-990 board. We replace the small stock MXL capsule with a quality LDC. Circuit and Capsule are carefully connected with point-to-point wiring. These are not kits from mic-parts or others. They are our own boards and the capsules are imported directly.

Harsh, sibilant high-end becomes smooth and silky. Thin bottom end becomes full. In the middle is a great harmonic richness that works well on almost anything you throw at it. The stock MXL headbasket can be left alone, Improved or Replaced.  We can improve it by removing some of the inner mesh layers. We can swap it out with a high quality replacement from (subject to availability).

Standard Upgrade:

  • Replace MXL SDC capsule with a K47-style or CK12-style LDC
  • Replace MXL Electronics with our fully discrete jaSb-990 circuit board.


  • Internal Cardioid/Omni Pattern Switch.
  • Improve the existing Headbasket by removing screen layers.
  • Replace existing Headbasket with one from Mic-Parts

Contact me first if you have any questions about the upgrade or the options.

The improved headbasket from mic-parts does not have the cardioid emblem on the front as shown in some of the photos.

There is a modest drop in output level when putting the mic in omni mode with the internal pattern switch


Additional information

Weight 4 lbs
Dimensions 10 × 12 × 8 in

2 reviews for MXL 990 Microphone Mod / Rebuild

  1. Don (verified owner)

    I’ve had my 990 rebuilds for a few weeks now and used them on vocals, drum overheads, and a baby grand piano. Honestly, they have been a pleasant surprise after spending 15 years on a shelf. As overheads, they handled the high spl really well and were nice and balanced and smooth on the top end. Meaty low mids and didn’t get sizzly and annoying in the high end like cheap mics often do. They sounded great on a male vocal. Clean, precise, and balanced. I didn’t love them on the piano, but it was more a matter of taste. They didn’t sound bad, I just prefer a SDC for that application. The results were perfectly usable. I have used a ton of cheap and mid priced microphones and realistically at the price point for the rebuild, there are a lot of mics you can buy, but these things will basically crush all of them. I even prefer these to my 214’s particularly on a vocal, but as overheads too. They are just livelier than the AKG’s, which are nice mics, but can be a bit of a dull sounding. The 990’s just sound more finished. I have yet to use them in Omni, so I’m definitely looking forward to more experimentation.

    Additionally, Bob was really easy to work with and communicated well. The turnaround was impressively fast. I sent them out on a Tuesday and had them back on Saturday. He also painted mine vintage green and replaced the grills and they look great!

    Bottom line, if you have a pair of 990’s on a shelf somewhere (who doesn’t?) I’d definitely recommend having them rebuilt as opposed to buying some other cheap mic. They don’t just sound good “for 990’s”, they are legitimately nice microphones now. I went in optimistic but skeptical, but am really glad I went for it.

  2. Tom Biller

    Bob will transform your MXL990 from a meh mic into an outstanding mic. Great for vocals, acoustic and electric guitars. Loved my first one so much, I picked up another one !!! Bob does things the right way !

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