The Catalinbread Formula 55 is a foundation overdrive that reproduces, in exact detail, the preamp section of the classic Fender tweed 5E3 Deluxe using an all-discrete JFET-based signal path. The volume and tone controls replicate, part for part, the circuitry of the 5E3, giving you authentic tweed amp response. The output section is designed to give you punch and volume with a low output impedance to drive your amp perfectly. Set the Hi-Lo button to "Lo" for the cleaner response of a vintage tweed. "Hi" is like hot rodding your amp by swapping in higher gain tubes. Big and powerful, yet refined, the Catalinbread Formula 55 melts into your amp, transforming it into a wide-ranging tweed monster.