Abstract: A power operated device that is mounted on a musical stringed instrument such as a guitar to selectively bring one or a desired group of rotating members into light pressure contact with strings of the instrument to cause one or a desired group of strings to vibrate at least so long as the rotatable members are in rotating contact therewith to emit musical tones. The device permits unusual and novel musical effects to be obtained from an instrument due to the strings being subjected to vibration for any desired period of time, in contrast to the short period of time a string vibrates to emit a musical tone when the string is plucked by a finger or with a pick.