Coreless Direct Drive Motor
The motor that forms the heart of the direct drive turntable is based on the coreless direct drive motor that was developed for the SL-1200G launched in 2016, and further improved. The double coil twin rotor-type coreless direct drive motor that was newly developed for this purpose had coils on both sides for 12-pole, 18-coil drive, with high enough torque to drive the heavyweight-class platter (approximately 7.9-kg). Offsetting the coils on both sides 60 degrees improved the rigidity of the substrate, suppressing fine vibrations and reducing self-inductance. These improvements achieved stable rotation of 0.015% wow and flutter or less, which is considered to be the measurement limit. Also, the thrust bearings supporting the heavyweight-class platter use a special engineering plastic to provide both high rigidity and reliability.
Suppressing Unwanted Motor Vibration
The motor that was developed for the SL-1200G served as the platform for the direct drive motor. The double coil, reinforced thrust bearings, and a chassis with increased rigidity achieved a stabilized motor with low center of gravity. By positioning two stainless steel weights with high rigidity and high specific gravity at the bottom of the chassis, the rigidity and low center of gravity are maintained. These thorough measures to prevent unwanted vibration help to achieve overwhelming rotary precision and improve S/N.
Heavyweight-class Turntable Platter
The turntable platter positions tungsten weights, which have an extremely high specific weight and are difficult to process, on the outer periphery of a 10-mm-thick brass weight. The brass weight is laminated onto the aluminium die-cast, giving the platter a total weight of approximately 7.9 kg and an inertial mass of approximately 1 ton･cm. A deadening rubber for eliminating unwanted vibration is also attached to the rear surface to form a 3-layer construction and achieve high rigidity and excellent vibration damping characteristics.
Separate Control Unit
The control unit is separated from the main unit to suppress the effects of unwanted noise on the main unit. In order to achieve a power supply circuit that provides good regulation for high torque, a switching power supply is used. To reduce the noise reaching the pickup, the switching power supply is equipped with a unique technology that provides a voltage supply with minimal noise by a newly developed “unwanted noise reduction circuit”. Also, to minimize the noise even during communication, a highly reliable system that resists the effects of external noise is used for communication between the main unit and the control unit. These thorough noise-reduction measures achieve the world’s highest-level S/N.
Minute Adjustment and Indication of Rotations
This turntable supports not only LP (33 1/3 rpm) and EP (45 rpm) analogue records, but also SP (78 rpm). Rotation (rpm) can also be set down to two decimal places (maximum ±16%) from the control unit. The OLED display is also capable of displaying rotation with accuracy down to two decimal places, so the user can both hear and see extremely precise rotation.
To enable the tonearm to precisely track the record’s rotation, Technics has traditionally used the static balance, S-type universal tonearm with a lightweight, high damping magnesium tonearm pipe. The gimbal suspension construction tonearm uses high-precision bearings. Highly skilled Japanese craftsmen handle all assembly and adjustment to achieve a high initial-motion sensitivity to precisely trace the grooves cut into the records. OFC is used for internal wiring, so the music signal relayed from the cartridge is not dampened and the musical energy cut into the record is not lost, thereby producing highly vivid sounds.
The tonearm base, to which the tonearm is mounted, is strongly integrated with the turntable part. Comparing the turntable base part with the tonearm mounting construction, the relationship of the tonearm bearings, turntable bearings, and needle position is always constant, providing a structure in which the vibration caused by the rigidity of the turntable base materials has minimal effect, and the tonearm performance is maximized. An optional tonearm base can also be purchased, enabling, in addition to the standard tonearm, an existing short or long-type tonearm from SME or Ortofon to be mounted (up to three including the standard tonearm).
A gold-plated 5-Pin DIN terminal is used, enabling the user to select the desired PHONO cable. An integrated, machined, high-rigidity aluminum housing also suppresses external noise from reaching the pickup.
A Rigid Cabinet and High Damping Silicon Insulator
The cabinet has a 2-layer construction consisting of BMC (bulk molding compound) and a 30-mm-thick aluminium top panel. The turntable part is a 3-layer construction comprising BMC, aluminium die-cast, and a 25-mm-thick aluminium top panel. This gives the system a construction of 5 layers of different materials to ensure sufficient rigidity. The insulator that supports the cabinet is a special silicon rubber that combines high vibration damping characteristics and long-term reliability. Reinforcement with a cylindrical tube made of a microcell polymer absorbs vibrations in the horizontal direction. These parts are contained in a zinc die-cast housing with high specific gravity, for isolation from external vibrations.