I have no microphone for my SB-100/102/110/401 rigs. I would like to get the Heil GM Vintage, which has an impedance of 30k ohms. In reading the material about the stock mic, the HDP-21A, its impedance is 100k ohms minimum. Would I be able to use a Heil with the SBs & just change the level, or is it more involved? Thanks!