I have started playing the upright bass with a group and had to put a pickup on my bass, and when I turn the volume up loud enough to be heard I get alot of feedback. How do I get rid of this? Thanks Bassman77

Try using a K&K preamp. I had one for a while and wish I had it back. WHen I had my Acoustic bass guitar plugged into it, it was nice and smooth. When I didn't, it fed back. Badly. Don't know why it was different, but it sure was.

Move the amp and/or your bass. It's feeding back because the audio signal that's going through the pickup is coming out of the speaker(s) and going straight back into the pickup. It takes a bit of EQing and repositioning to get it right.