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[Nicolas_D]

Hello everyone !

I recently bought a Neumann KM84 for my recordings. The microphone works fine, but the body does not look very good (scratches and tiny impacts on the paint, and an engraving from a previous owner I'd like to remove). Nothing too serious, but as it's a great microphone, I'd like to rejuvenate it to its former glory.

My initial thought was to remove the electronics and the capsule, then strip the paint with sand paper or a dremel (and, if possible, remove the engravings as well). Then, I could paint it again (if I find the right type of paint).
But as the body seem very thin, I wonder if I have enough thickness to do this without causing serious damages ...

What are your thoughts about this project ? Any advice is welcome !

Thanks !

Nicolas Dedieu
Classical music composer

[klaus]

Hello Nicolas,
Visually restoring a blemished vintage microphone is a matter of multiple considerations: personal taste and esthetics, generally accepted cosmetic practices in the field, the effect on the mic's value, and, as you already mentioned, considerations of performance and mechanical stability.

Self-evidently, I cannot comment on personal taste, but accepted practices what to do an what not - including the effect on value of a less than perfect looking housing components - are that a blemished housing tube is preferable to one that has been repainted or otherwise surface restored. Practices in this field are similar to what is commonly done with major paint flaws and gouges on vintage guitars: leave the finish alone, do not touch up, do not repaint.

Consider that removing the thin nickel plating on the KM84's housing will expose the goldish hue of the brass the body is made of. Measure the depth of the engraving to make sure that enough brass material is left to still keep the housing tube mechanically stable.
If you decide to paint, I suggest you fill, rather than grind off, the engraved section, to keep the original thickness of the body largely intact.

Send us a picture if you decide to paint!

[radiovinhet]

If you really wanna paint it, try to find an epoxy powder paint specialist, the finish is great! By the way, i have a Beyerdynamic MC 837 , black matte, wonderful job!

[Nicolas_D]

Hello Klaus,
Thank you very much for your answer, I'm very grateful to have the opinion of an expert like you in microphone restoration !
I did not take a decision yet. I wanted to take advice from professionals first, to see if it was a good idea or not.

Here's a picture of the microphone. The painting is not that bad, but the engravings bothers me a bit more, so filling them seems a good idea if I decide to repaint it.

In your opinion, what would be the softest method to get rid of the paint without removing too much nickel ? Sand paper ? Dremel ? Steel Wool #000 ?
In any case, I'd also like to clean the insides (of course, I won't open the capsule, as it's beyond my skills). I already took out the electronics, but is there a way to remove the white plastic ball in which the pin of the capsule goes ? There is some dust in it that I would like to remove ...

[Nicolas_D]

Thank you also Radiovinhet for your advice ! I already heard of epoxy powder coating, but did'nt know if the finish was good for a microphone body ...
I'd be curious to see a picture of your microphone, if you agree to share it ! 

[klaus]

You had not mentioned before that yours is a KM84mt (matte/TV-gray anodized), which makes restoring its surfaces much more complicated, if not impossible:

Unless you take the capsule completely apart to its component level, and unless you are able to reassemble and recalibrate these components to factory specs afterwards, you cannot remove the head's anodized layer without jeopardizing capsule performance.

That would leave you with possibly a perfectly re-anodized housing tube, combined with a beat-up head that could not be restored.
Disassembling the connector housing that contains the serial number from the amp an then re-anodizing it is another delicate operation.

So, do it like John Mayer getting sweet tones out of his relic'd beat-up 1960s Strats: record good music with your mic as is, and, added bonus: people will pay not that much less for your KM84 in its current condition than if it were cosmetically flawless (my guess: you already have doubled or tripled its value by now!)

[Barry Hufker]

Personally, I would keep the microphone as-is.  The engraving is now part of the microphone's history.  If the microphone performs well, I wouldn't worry about it.

[Nicolas_D]

My bad, I forgot to mention that detail.
It seems that I underestimated the difficulty of the task ... I thought I could just cover the grill and the back of the capsule with some kind of tape to protect it from the paint, but I see now that it's probably not enough to keep it intact !

I'll do as you suggest and keep the microphone like this.

Thanks again for your advice!

[Kai]

... I thought I could just cover the grill and the back of the capsule with some kind of tape to protect it from the paint, but...

Vapor from solvents – either from paint or from cleaning attempts - dilute the diaphragm material and thus kill the capsule.
Even small amounts have this effect, as the diaphragm is that thin.

Just as a warning if one has such an idea.

Only dry cleaning should be done on a condenser mic.

[Nicolas_D]

That's good to know, thanks !

[David Satz]

To be very blunt, if it were me in this situation (and I have been in it more than once) I would almost certainly buy a new capsule from Neumann. That is where 80% or more of the sound quality of the microphone comes from, and if the surface has been damaged enough to be a concern, then the innards should be even more of a concern in my opinion.

I don't mean to throw cold water on do-it-yourself efforts where appropriate, or where nothing important is at risk. A lot can be learned that way. But I find that good capsules are nothing to mess with--and again I speak from multiple experiences that I really wish I'd never had; a lot can be learned that way, too ...

--best regards

[Nicolas_D]

Thank you David for your suggestion, if I had more money, that's probably what I would do !
My capsule is a bit worn out but doesn't sound bad (I didn't open it or repaint it), so the microphone is still very usable.
As you said, the do-it-yourself thing is a great way to learn, and that's why I like to experiment by myself.
But when I'm not sure of what I'm doing, I always seek advice from experts, and thanks to you guys, I have avoided making a big mistake !