I ended up taping a musical last night which I don't do very often. I brought all my audio gear to pull from their board. They were running 10 wireless's and had other mics dropped from the ceiling. They had a 1/4" main out on the back which I pulled from. I fed their board into a splitter then one went directly into the cam and the other was feed into a mackie mixer with a ground lift then into the cam. Both have that buzz which was not there in the beginning. It starts about 10 minutes in and lasts until the last 10 minutes. Is there a way to get rid of this?