I'm not really hearing any hum myself. Its being reported to me as an rf hum by
other hams.
I can disconnect the mic cord from the mic itself. I've replaced the cord but
no joy. Heil has looked at the mic and says its fine.
Tom
Tom Brennan KD5VIJ, CCC-A/SLP
web page http://titan.sfasu.edu/~g_brennantg/sonicpage.html