Abstract: A string instrument, such as a guitar, includes an instrument body, a neck portion, pivotably coupled to the body by means of a joint, to permit pivotal movement of the neck portion between an operative and a folded position, a string mount moveably mounted on the body, at least one string, one end portion of which is secured to the string mount and the other end portion of which is secured to the neck portion, and drive means for moving the spring mount, which is coupled to the spring mount and the joint. The drive means moves the spring mount in direct response to pivotal movement of the neck portion about the joint, so as to maintain the original length and tension of the at least one string, when the neck portion is moved between the operative and folded positions thereof.