At a gig, discovered my DS-5 had died so i used the batteries that had been in my series bass for quite a long time. Low voltage or low current - whatever happens to batteries when they're dying - resulted in the most fantastic Jack Bruce distortion. Probably the best fuzz sound i've ever had, warm, responsive... I'm considering asking for a dial to mess with the power supply for those times when i want that as an option. Conversely, that showed me that the way to clean headroom-rich sound was using the regulated supply, where the pre's get the juice they're designed for.