** Do the test I suggested with a length of insulated wire, XLR and
pre-amp. Then think how a voltage is created in the coil of a dynamic, mic
sent down the cable to the pre-amp and is amplified. Then realise that the
connecting cable is just an extension of that same coil.

Recall that a dynamic mic hums when placed near an AC power transformer (
except for those with effective, internal hum bucking coils).


ok, got that. but what about when the cable runs next to an AC
transformer? that's the part that i don't quite get -- i don't see
how it could induce current in one conductor in opposite polarity with
the other.

btw, i don't understand the voltage vs. current induction thing -- my
physics book says a moving B field will induce a /current/ in a coil.
what am i missing?

thanks,
chris deckard
saint louis moe