GB538058A - Improvements in or relating to moving coil pickups - Google Patents

Abstract

538,058. Gramophone pick-ups. VOIGT, P. G. A. H. Jan. 12, 1940, No. 757. [Class 40 (iv)] In a pick-up in which the coil does not embrace a stationary part of the magnetic circuit, an elongated coil wound lengthwise is supported by self-positioning means, such as by clamping or bedding in resilient material, the coil being operated (1) by rotary vibration about an axis close to which the conductors lie, or (2) by bodily movement for use with hill-anddale records, or (3) by both (1) and (2) for combined lateral cut and hill-and-dale records. The coil former may consist of a central lamination A, Fig. 1, and two side laminations B combined as at C to leave a projecting strip around which aluminium wire is wound lengthwise. The coil is surrounded by two rubber' rings F or by a continuous rubber sheet and mounted in the magnet gap so that it can rotate for lateral-cut records or move bodily in the gap for hill-and-dale records. To improve visibility of the needle and reduce magnetic leakage when a ferrous turntable is used, the magnetic system may comprise block magnets and sloping pole-pieces, Fig. 4 (not shown). In a modification, the coil may be mounted on one side of the lamination as shown in Fig. 5 (1), part of the coil lying outside the magnetic field as shown in Fig. 5 (2). Two coils mounted in this way may be connected in series and parallel as shown in Fig. 5 (3) to two transformers, so that voltages corresponding to lateral cut may be obtained from the upper transformer and to hill-and-dale cut from the lower transformer. The laminations A, B, Fig. 1, may be of magnetic material.