Steve - I believe the answer to your question, "Can the Heil GM-4 work with the 10k hooked up from AF to 5V?" is yes. The Heil Icom cables for the GM microphones have a capacitor that isolates the 5V from the GM microphone element. See the description of the Icom setup on the Heil web site -> http://www.heilsound.com/amateur/tips/all_icom.htm