The Tornado is a class A, single-ended overdrive using JFETs throughout. The close similarity between JFETs and valves allows the Tornado to be effectively the front end of a classic high gain guitar amp but implemented in miniature and running from only 9 volts instead of the 2 or 3 hundred volts required in a valve guitar amp. The result is an overdriven sound that is much closer to that of an amp than a typical pedal but, with pedal convenience.