Some of the b band preamps are hissy especially when the treble control is turned up past the midway point. It's just how they are. Occasionally you can find one that's a bit quieter. Do check that there is not a problem with the pickup strip itself, they can have issues where the pickup is balanced but the output low so that the signal to noise ratio is wrong. Try replacing the pickup itself, or and make sure it's properly seated. Remove the saddle carefully lift out the pick from the bridge slot and put it back in again. Make sure the saddle is not to tight in the bridge. I've fitted loads of b bands and most of the problems come from (issues?!! ) with the pickup strip. When working correctly they sound quite good.