The Capicitor that is in parallel with the Zener Diode should be a tanalum chip type capacitor. The Zener Diode should be 12v.
This is the Circit diagram for the 1st version of the mic. This version requires a +48v phantom power source, or phantom power from a mixer.
I finally tested this, and yes it does work! It works pretty darn good too. It is the same basic design, just with a 9v battery circuit.