The Icom HM-36 mike works, and the improvement is breathtaking! The highs come through much better--it doesn't sound so muffled. It still could use a little boost, although simply increasing the mic gain on the front panel still pushes the voice into distortion--so I'm not sure a preamp would do any more good. What exactly did you do?
Jack, N6LN
John Terrell, N6LN