What is old is new again. I purchased these microphones in the early 1970's when I was in college selling stereo equipment. I thought I would use them for recording acoustic guitar and vocals. That did not happen, they are almost new. Lol...

I have a need to use them now. I am in a rock cover band. We have some nice Shure and AudioTechnica mikes for our vocals. I want to use them to mike our drummer's kit. This was suggested in an older thread, "electret condenser?" We have an active mixer that accepts both 1/4" (single-ended) and XLR (balanced) inputs. The Sony mikes are currently set at 10K ohms and wired single-ended to 1/4" plugs. They work fine, but feedback comes up quickly.

My newbie questions. In this application, should the impedance be set at 200 or 10K ohms? Is there any way of wiring these mikes for balanced (XLR) use?