I got my GK in the mail on Friday and used it on my gig last night. It was a jazz trio with piano, bass and vocals so the volume was low and the GK was more than enought to fill the room. I have a carved Weiss bass and a Realist pu and they both seemed to work good with the amp. I left the contour switch off and contour levels at zero like it suggests for URB in the manual. Everything else was set fairly flat but I did drop the bass a tad and boosted the high and low mids. The room is carpeted and has a pretty muffled tone to it. Overall I dug the sound I got from the GK MB150 but I would like to have a bit more high end cut to my tone than I had last nigt. I want to wait and get used to the amp before I go turning lots of knobs on my first gig with it . I was most pleased with the 25lbs and what that meant to my easy load in and out.