Unfortunately, most standalone microphones will not work with the Headset Buddy. The Headset Buddy WILL work with headsets that have a microphone embedded and PC microphones.
The reason most standalone microphones won't work is because the phone supplies the power for the microphone. Because the phone supplies the power, it only supplies very little power, and can only power small microphones such as those in headsets and PC mics. Shotgun microphones, stereo condenser microphones, and most other standalone mics won't work with the Headset Buddy, or any other phone adapter for that matter.