The Hitachi HT-68 record player is 17-1/8 inches wide, 14-3/8 inches deep, and 4-1/4 inches high. The adjustable counterweight has a tracking-force scale calibrated from 0 to 3 grams at intervals of 0.1 gram. The turntable specifications include 0.025 per cent wow-and-flutter (wrms), a tone-arm tracking error of less than 2 degrees, and a lead-wire capacitance of 140 picofarads. It is supported on four softly sprung mounting feet. The HT-68 is mounted on a silver-colored plastic base molded of a compound that is claimed to minimize vibration transmission to the pickup and record, thus reducing acoustic-feedback tendencies. The player, of course, shuts off automatically at the end of a record, and it can be operated manually by lifting the tone arm from its rest (which starts the motor). A large flat plate serves as the start/cut switch, initiating and terminating a playing cycle on alternate operations. LED indicators next to the last three momentary-contact buttons show when they are engaged. Very-light-touch pushbuttons are used for power switching, speed selection, repeat-play mode, and the tone arm's up/down (cueing) function. At the end of play another optical sensor initiates the arm return and shut-off cycle.Īll operating controls of the Hitachi HT-68 are located on its top front edge, where they are accessible with the clear plastic dust cover lowered. This information is used to determine turntable speed and the tone arm's indexing diameter (the arm will not leave its rest unless a record is present). As the platter rotates, light reaches a photocell beneath it through any holes not covered by a record. This is done by means of small holes at 90-degree intervals around the platter and mat (at diameters of about 5>/2 and 11 inches), illuminated from above by a light near the turntable rim. The HT-68 employs a photosensor system to detect the presence and size of a record on the turntable. motor, so that record rotation is completely unaffected by tone-arm movement. The arm's automatic operation is handled by a separate d.c. The HT-68 is furnished with a Hitachi MT-35 dual-magnet cartridge, but the detachable plug-in shell accommodates all standard cartridges having 1/2-inch mounting centers and weighing between 4 and 9 grams. The inner surface of the straight stain-less-steel tone-arm tube is chemically treated to damp its mechanical resonances. The cast-aluminum-alloy platter (with its rubber mat) weighs about 2 pounds. servomotor is controlled by a quartz-crystal oscillator, giving it a speed accuracy of 0.003 per cent at 33 V3 and 45 rpm. The rotation of the brushless, slotless, and coreless d.c. The Hitachi HT-68 two-speed direct-drive turntable uses a "Unitorque" motor said to have a constant (nonpulsating) torque characteristic that results in very low rumble and flutter levels.
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