shown in fig4 thus it will be seen that rotation of the magnetic friction drive structure 81 about the axis of the shaft 96 will also tend to impart rotation to the drive cylinder 141 due to the contact between the conical exterior surface of the driving cone 140 and the conical interior surface of the drive cylinder 141 as best shown in fig3 the sound track is recorded on a pair of record discs 80 each of which is mounted on a different one of the drive cylinders 141 and 142 the drive cylinders 141 and 142 each of which carries a disc 80 are mounted for rotation within the sound track unit 20 as will now be described as best shown in fig3 and 3 the sound track unit 20 comprises a rigid frame 150 in the form of a hollow open ended rectangular box flanged cover members 151 and 152 each of which is provided with apertures 21 and 22 for receiving the driving cone 140 as well as apertures 25 and 26 for receiving the needle 78 of the pickup unit 73 close the open ends of the box formed by the frame 150 with the record discs 80 and drive cylinders 141 and 142.