Stereo pickup with printed circuit coils mounted in a linear field

Abstract

A moving-coil type stereo pickup cartridge comprises a vibration mechanism, including a stylus for tracing the groove of a sound track on a record disc, at least one coil plate provided in the vibration system and adapted to vibrate in response to vibrations of the stylus, and a structure for forming a magnetic field for the coil plate. The coil plate comprises a thin insulative substrate and a pair of left and right coils substantially symmetric with respect to a center line and formed by an electrically conductive thin film placed in a spirally wound pattern on at least one surface of the substrate. The magnetic field-forming construction comprises a permanent magnet and a pair of yokes adapted to clamp the permanent magnet. The pair of yokes have confronting surfaces for defining a gap in which the coil plate is interposed and a recessed substantially reverse V-shaped notch or cutout. The notch is defined by edge parts or facets. The configuration of the edge parts is such that the contour lines of the density of the leakage magnetic flux at least within the space confronting the coils and in the notch extend substantially at angles of plus and minus 45.degree. to the center line.