tbd

Here's a schematic...

The transistors I used were 2N5087. The microphone capsules were WM-61A, available from Digi-Key. Note that Linkwitz modification must be done to the capsule, as shown here...
http://www.mp3forkidz.com/mic/mod.html

Here's a PCB layout...

Part of the inside of the Neutrik connectors had to be cut away to make room for the PCB, as you can see in the next pic...

Here's the PCB...

And, here's the interior assembly...

The rubber boot didn't quite fit all the way back onto the XLR connector when I reassembled them. So, as you'll notice in the picture at the top of this page, I used some black electrical tape to secure the boot back on to the XLR connector.