Abstract: A stringed instrument having a device for sustaining the vibration of a string; the stringed instrument being a musical instrument having plural strings with the mass and tension of each string being different, which has a pickup unit for detecting the vibration of a string, an amplifying unit for amplifying an electric signal detected by the pickup unit, an electromagnetic driver for emitting magnetic energy to drive a string by a driving signal output from the amplifying unit, and an excitation balance matching unit for providing well-balanced excitation to each of the plural strings and/or a magnetic flux emission controlling unit for increasing the quantity of magnetic flux emission in the direction of a string.

Abstract: An electromagnetic pickup for an electric stringed instrument has, two parallel permeability plates placed perpendicular to strings; a permanent magnet provided between the two permeability plates in parallel to strings; and a coil wound around the permanent magnet. The plate permanent magnet is in contact with the permeability plates in such a manner that the portions of the permanent magnet that contact the permeability plates have oppsite polarities.

Abstract: An electric stringed instrument comprises an electromagnetic pickup having a permanent magnet and a string signal detecting coil wound around the permanent magnet and magnetically combined with the permanent magnet, an electromagnetic force producing unit having a driving coil to produce a magnetic force and being placed in the neighborhood of the electromagnetic pickup, and an adjusting unit provided with a part of a current flowing in the driving coil of the electromagnetic force producing unit and disposed at a place magnetically combined with the string signal detecting coil of the electromagnetic pickup. One induced electromotive force caused by magnetic flux from the adjusting unit and another induced electromotive force caused by magnetic flux from the electromagnetic force producing unit negate each other in the string signal detecting coil.

Abstract: An electric stringed instrument having a device for sustaining the vibration of the string including an electromagnetic pickup for converting the vibration of the string to an electric signal, an amplifying device for amplifying the electric signal, and an electromagnetic driver for converting the amplified signal to a driving force to thereby drive the string. The electromagnetic pickup and the electromagnetic driver are placed at a right angle or a predetermined angle of inclination relative to each other so that induced electromotive forces caused by magnetic flux from the electromagnetic driver negate each other or do not occur in the electromagnetic pickup to thereby reduce the magnetic feedback in the device.