After reading a lot about the semi-famous Oktava MK-219 and MK-319 microphones online, and the various mods to improve them, I took the plunge and procured some used ones.
Here's the first victim, an MK-219 from 2001. This mic is a large diaphram condenser mic which sounds pretty decent unmodified. But there are a lot of popular mods to improve...or change it.
The microphones are made in Oktava's factory in Tula, the adminstrative center of the Tula Oblast in Russia.
I used Scott Dorsey's article as a reference point, as well as other references on the interwebs. If you do a search, you'll find a lot of information about these mics.
The most basic mod is to cut away the bars on the headshell around the capsule to open it up, and to add deadening material to the body to cut down on the 'ringing' produced when the mic is vibrated, which affects the tone.
It's easy to open up; take off the ring around the XLR socket, then remove the screw that holds the body halves together.
I used a wood wedge to drive the body halves apart. I didn't want to scratch the paint off, so I didn't use something metal to do this.
Just unscrew the rod. And don't lose it!
Be careful around the microphone capsule at the top! If it gets punctured it will cease to work.
I put the whole chassis safely aside while I worked on the body.
If you tap one of the body halves, you can hear it ring instead of 'thunk.' We're going to remedy that.
The stock mesh comes out easy - just pry it out. It's not glued in.
They're close together, so I used small snips to start cutting in one area, then I used larger snips to cut the remainder away.
While I was cutting, I had the occasional 'ping!' when a chunk of material flew off and went into never-never land.
The stock mesh as seen on the left has about 22 or so openings per inch. The nice Microphone-Parts.com headbasket I put on my modified MXL 990 has about 10 or so openings per inch.
I followed that lead and procured some mesh from McMaster-Carr with more openings to use instead of the stock mesh.
This is stainless steel mesh screen - I bought a sheet with 10 spaces per inch and one with 12. I wound up using the one with 12 spaces for this project.
I found that the mesh with more spaces is a lot easier to bend to shape. The screen with less spaces (such as the screen I used) is a lot stiffer and harder to work.
Scott Dorsey and others have used RTV silicone to damp the body. That looked like a real mess to work with, so I decided to simply use some CLD (Constrained Layer Damper) tiles left over from my SAAB c900 sound deadening project. I put one large piece and one small piece on each half.
I probably used more than I needed, but I figured I'd put a big hunk in there for good measure.
Works amazingly well and it's a more elegant solution than the silicone I think. And nowhere near as messy.
Next time we'll work on the electronics.