Abstract: A stringed musical instrument of the Hawaiian guitar type has a plurality of parallel strings that are led through a plurality of tensioning pins. The pins which are spring loaded in a tensioning attitude, may be partially moved in an upwardly direction to release a portion of the tension on a string. A plurality of levers are arranged to engage the ends of the pins to achieve the movement and the levers are moved by a plurality of cams that are mounted on shafts that extend transversely across the levers. The shafts are coupled to foot pedals.