I'm not sure where to post this because I'm not sure what the problem is. Today at practice I started getting very loud feedback. I was using a GK MB210 along with the 210MBE cab. My bass was a Fender standard jazz. We practice at the same place each time and I never had this problem. The only thing different was I had replaced my chrome flats with nylon wrap strings. I know I read that there can be a "grounding" issue using nylons...do you think that may have been what was causing the feedback? I really don't know if I was or wasn't touching the bridge when playing or when the feedback occurred. Like I said, the nylons were the only difference in my set up today. Thanks for your time and any help you may offer.