A great sounding mic can be made for under $20. The Panasonic WM-61A electret capsule (~$5 on ebay) can be modified to be used as recording or reference microphone.
The mic (which is omni-direcitonal) is phantom powered with a 9V battery. This is the simplest and most noise-free method of powering the mic.
The panasonic electret capsule must first be modified, by cutting the trace at the rear of the capsule that connects terminal 2 to ground.
The capsule is wired to a coaxial cable, and a sturdy diecast aluminium enclosure houses the circuit, which is point to point wired.
Schematic
The circuit for this mic was taken from Linkwitz Lab
The panasonic electret capsule must first be modified, by cutting the trace at the rear of the capsule that connects terminal 2 to ground.
The capsule is wired to a coaxial cable, and a sturdy diecast aluminium enclosure houses the circuit, which is point to point wired.
The circuit for this mic was taken from Linkwitz Lab
