A foot control for control of musical effects from a musical instrument, the instrument having an electrical signal output operable to send signals to a speaker system, the control having a housing with at least one side wall; a roller rotatably mounted in the housing, a roller surface portion exposed and extending away from the housing for contact by a foot, to enable rotation of the roller by the foot; and, circuitry within the base connectable with the instrument and operable in response to rotation of the roller, to vary signals from the instrument.