R/E/P Community

R/E/P => Klaus Heyne's Mic Lab => Topic started by: hugovanmeijeren on May 23, 2016, 08:00:50 am

Title: Neumann KM184 Unscrewed Capsule: Screwed?
Post by: hugovanmeijeren on May 23, 2016, 08:00:50 am
Hi all,

I recently acquired a cheap second hand Neumann KM184. Upon inspecting the microphone, I noticed that the little pin that goes up to the capsule was unscrewed from the capsule, causing the pin and plate to which it is connected to lie loose on top of the microphone body.
Can I just carefully screw the pin and plate back back together (I noticed a small plastic pin behind the capsule that probably ensures the proper spacing), or does this capsule need factory alignment?
Title: Re: Neumann KM184 capsule unscrewed
Post by: klaus on May 23, 2016, 01:43:42 pm
Depends on whether the 6 spacer between back place resonator and backplate was dislodged when the needle came out (it's centered and held in position through the contact needle).

If the spacer was dislodged (which is hard to tell without completely disassembling the capsule's elements), it is impossible in a home repair to properly reposition it. In that case you will need to have the capsule re-calibrated by a competent microphone specialist.
Title: Re: Neumann KM184 capsule unscrewed
Post by: hugovanmeijeren on May 24, 2016, 05:40:55 am
Hi Klaus,

Thanks for your reply.
Are there any hints you can give in determining whether it could be that this spacer was dislodged? If I put everything back together, but this spacer is dislodged, in what way would I know this is the case?
I know you've said that it will be hard to tell without further dismantling the capsule, but maybe there might be something I can try to check first?
Title: Re: Neumann KM184 capsule unscrewed
Post by: klaus on May 24, 2016, 11:50:19 am
The only hint would be unbalanced sound; specifically, unbalanced, honky mids and/or compromised cardioid directionality. trending towards omni.
Title: Re: Neumann KM184 Unscrewed Capsule: Screwed?
Post by: hugovanmeijeren on May 30, 2016, 04:33:08 am
Alright, so I tried to put the capsule back together again last weekend, but it didn't work as it should.

When I reinsert all the parts to the capsule and attach it to the microphone body, I can hear a "woosh" (wind like) sound that cuts in and out. Only when I hold the microphone upright (capsule pointing to the sky) the woosh sound stops and I can hear (albeit very softly) my voice when speaking into the microphone.

To rule out any other possible defects in the electronics, I have tested with a known good capsule and everything works perfectly.


So, it looks like not all the parts are in the right place. However, I'm still interested to undertake some more steps in getting this capsule to work again. Klaus, you talk about this spacer between back plate resonator and backplate. Just to be 100% sure about the terminology, the part that's called the resonator is the little round metal plate that is closest to the microphone body when screwed together? (I've attached a picture of the parts I have, would it be the piece in the upper right corner of my picture?)
If so, there's no spacer ring between this and the backplate...

If you look closely at my picture, you can see a circle in the middle of the backplate, I presume this is the location where the spacer ring should have been?
Title: Re: Neumann KM184 Unscrewed Capsule: Screwed?
Post by: klaus on May 30, 2016, 02:27:40 pm
You are correct on all accounts. Look around where you first disassembled the capsule- maybe the aluminum spacer can still be found?

If not, contact be privately, I may be able to help.