Just open the back panel and turn the small white dial (using a small philips head screw driver) counterclockwise to reduce the boost...
J
While we're on the subject, where do most of you set your preamp boost to, and why?
I'm not sure I see a high advantage to running it at super high levels. I thought it made sense to keep it close to the passive volume in case I want to switch. When I first got, it was the hottest active bass I'd ever owned.