I've been using a GSP1101 (C63) and a Boogie 50/50 power amp for quite a few years. However, I've never been able to get a good sound going out the XLR right to the board and we always end up micing the cab. The XLR to the PA always sounds small, thin and fuzzy while the sound going out of the 1/4" outs to my power amp and then to my cab sounds great. I've tried the -10 and +4 and Variable settings on the XLR out. I've tried both XLR's with the stereo setting and one XLR with mono setting. I have it set to use a universal cab to the XLR's only (Digitech Alt 4x12). I'm guessing there is an output level I need to adjust. Or do I need to ask the soundman to adjust the board a certain way? Anybody have any tips or specific settings I need to try?