I love my Fat Fuzz Factory. Which is why I'm sorry it took so long to stick a carbon-zinc battery in there rather than running it off a power supply. I had read all the testimonials about how these are the right batteries to use in fuzzes, but figured I liked what I was hearing already so I needn't bother. I was so wrong. Ordered a pack of carbon-zinc batteries that arrived today and I'm not even kidding when I say it turned my FFF into the fuzz that dreams are made of. The signature crackle of Mr. Vex's pedal has been replaced by beautiful smooth- yes, smooth- and sustaining fuzzzzz. It's even made the sub-switch more useful. Incredible, but I totally get it now. Anyone serious about fuzz or even just casually into it owes it to themselves to try carbon-zinc batteries, I'll never power that pedal with anything else going forward.