The Scrabbler is the circuit from the old Ampeg Scramber stompbox. (any trademarks used here do not belong to General Guitar Gadgets). (Once) rare and always exciting, this beast can mangle your sound, provide a unique blended distortion or anything in between. It has a “Balance” control feature that lets you blend in the dry guitar sound for lots of tonal variation. Some notable players include Jorma Kaukonen of Jefferson Airplane, John Cippolina of Quicksilver Messenger Service and Jim McCarty of Cactus.

Description from General Guitar Gadgets.