A footswitch provides remote channel selection and drive/more drive switching Thank you fforr choosiing Fenderr®—The Worrlld’’s mostt popullarr iinsttrrumentt amplliiffiierrs—siince 1946 A. INPUT - Plug your guitar in here. INPUT 1 is normal sensitivity for most guitars, INPUT 2 is lower sensitivity for guitars with high output (active) pickups. B. VOLUME - Adjusts the loudness of the Normal channel. C. TREBLE/MID/BASS - Adjusts the high-, middle-, and low-frequency tones of the Normal channel.