Abstract: An improved stylus assembly for a phonograph cartridge is provided. The assembly includes an arm having a jeweled stylus attached to one end thereof. The arm is formed of a hollow aluminum tube which has been anodized so as to form an aluminum oxide skin about the outer surface thereof. The skin extends for no more than one-half the thickness of the arm.

Abstract: A rotary differential transformer is provided which has a constant amplitude output the phase angle of which varies with the angular displacement of a rotor. The rotor contains a pair of core segments of magnetic material which serve to couple portions of first and second primary coils to a secondary coil. The primary coils are connected to AC sources 90.degree. out of phase with each other.

Abstract: A differential transformer is provided comprising an elongated secondary winding of uniform turn density. First and second transformer primary windings are wound about the secondary winding. The primary windings lie generally in parallel spaced apart planes which cut the axis of the secondary winding at an angle other than 90.degree.. A core of magnetic material is movable linearly along a path parallel to the secondary winding axis and serves to couple the primary and secondary windings. The primary windings are connected to AC sources which are 90.degree. out of phase with each other.

Abstract: A miniature sounder having a diaphragm closing one end of a tuned chamber. The other end of the chamber communicates with the interior of a tuned housing through which an open-ended enclosure extends. The oscillating frequency of the diaphragm. The housing and enclosure are tuned to resonate at the desired frequency.

Abstract: A rotary variable differential transformer is provided having a substantially linear output over .+-.35.degree. of rotation of the rotor. Two secondary windings in series opposition extend over adjacent nominal quadrants of the stator. A primary winding extends about substantially half the stator. The rotor includes two diametrically opposed pole pieces each defining arcuate segments. One segment is approximately one half the arcuate length spanned by the secondaries and the other segment one third the arcuate length of the remainder of the stator.

Abstract: A rotary variable differential transformer is provided comprising a pair of RVDT units disposed along a common shaft. A third RVDT is positioned along the shaft between the two units. The third RVDT comprises two pairs of secondary coils each pair being connected in series opposition. One of the coil pairs is connected to the secondary coils of one of the RVDT units and the other pair is connected to the secondary coils of the other RVDT unit. The third RVDT unit does not contain a primary and its secondary coils are excited only by the leakage flux from the other units.

Abstract: A turntable to enable playback of record matrices and stampers is provided. The turntable rotates in the direction opposite that of a conventional turntable and is provided with a tone arm carrying a stylus designed to ride the ridges of the stamper. Magnetic members on the table support surfaces hold the stamper flat to prevent "oil canning". The magnetic poles of the members are oriented radially to minimize the effect of the magnetic members on the turntable transducer. The tracking force of the tone arm is variable by means of a sliding weight.

Abstract: A phonograph cartridge replaceable stylus assembly is provided. The assembly comprises a housing having a nonmagnetic tube affixed thereto. The tube has a forward end and a rear end extending outwardly away from the housing. A nonmagnetic stylus arm extends through the tube forward end. A jeweled stylus is mounted to the front of the arm. The rear end of the arm passes through an elastomeric damper positioned within the tube. The damper serves as a universal pivot joint for the arm. The damper comprises a cylindrical member having a forward edge and a rear edge. The tube is crimped along a circular crimp line engaging the damper intermediate the forward and rear edges with the portions of the damper that do not engage the crimp also being free of the tube. A magnetic member is positioned within the tube secured to the arm and adapted to move therewith in response to motion of the jeweled stylus and following the grooves of a record.

Abstract: A cueing control is provided for a phonograph turntable of the type including a frame, a record supporting disc affixed to the frame and mounted for rotation about a central axis, and a tone arm having a cartridge assembly affixed to one end thereof. The cueing control comprises a post mounted to the frame for vertical movement and having a cradle affixed to its top end designed to underlie portions of the tone arm. The bottom end of the post is engaged by one end of a bimetallic element which, in turn, is cantilevered to the frame. A heater is positioned adjacent to the bimetallic element so that the element can be heated and caused to deflect to thereby shift the post vertically.

Abstract: A playback stylus assembly for a phonograph record stamper and matrix is provided. The stylus assembly comprises a pair of conventional jeweled styli members each terminating at a tipped end. The styli are bonded to each other but offset from one another to form a "V" to ride along the stamper ridges. The ends of the styli opposite the tip ends are bonded to a tube.

Abstract: A playback stylus for a phonograph record stamper and matrix is provided. The stylus comprises a pair of substantially cylindrical jeweled members each terminating at a tipped end. The members each have a flat surface defining a plane parallel to its longitudinal axis. The members are bonded to each other along the flat surfaces with the tip ends aligned to form a "V." The ends of the members opposite the tip ends are bonded to a tube.

Abstract: A phonograph cartridge replaceable stylus assembly is provided. The assembly comprises a housing having a nonmagnetic tube affixed thereto. The tube has a forward end and a rear end extending outwardly away from the housing. A nonmagnetic stylus arm extends through the tube forward end. A jeweled stylus is mounted to the front of the arm. The rear end of the arm passes through an elastomeric damper positioned within the tube. The damper serves as a universal pivot joint for the arm. The damper comprises a cylindrical member having a forward edge and a rear edge with one of the edges engaging the tube and the other edge being free of the tube. A magnetic member is positioned within the tube secured to the arm and adapted to move therewith in response to motion of the jeweled stylus and following the grooves of a record.

Abstract: An anti-skating device is provided for a phonograph turntable of the type including a base, a post extending longitudinally from the base and a tone arm supported for rotational movement about the post. The device comprises an elongated weight disposed about the post, means extending between the weight and tone arm connecting the two whereby the tone arm rotates with the weight, and means for applying a torque to the weight tending to rotate the weight about the longitudinal axis of the post to thereby apply a torque to the tone arm counter to the skating torque of the tone arm.