Anyone use one of these? I have two in hand. Bet you could get it to work with a dynamic mic as well - just accommodate the electret bias current, cap decouple to the Vcc/2 signal midpoint. Specs on the IC parts seem impressive for the $10 decade of expenditure. Ok, it's not a $35k Fairchild 660, but maybe with some I/O transformers? One would think you could build it right into the mic and have a vocal mic that "just does it".