Man, was I happy to find this mic (and this forum!). I play bluegrass and folk, and the guitar I use most of the time has a great sound but isn't loud enough to compete with other instruments. I was getting tired of moving back and forth into mics!
So far, I've used the Pro 70 only twice. The first time, it was great. I loved it. No problems. Great sound. Throughout the show, I experimented with different placements of the mic until I found one that suited me.
The second time I used it, I had trouble. We kept getting this loud roaring low end feedback. We couldn't figure out what the problem was. I even kept accusing our bass player of causing the trouble. I kept saying "Mute your strings!" Of course, I was the problem. Something in the Pro 70 wasn't working.
I could mute my strings and turn the power pack on and we would get that low roar. I took the battery out and used straight phantom power. Same problem. I switched cords. Same problem.
The only time it wouldn't roar was when I was playing. After a song, roar. Turn on the switch, roar.