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 stabilised motor with low centre 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 centre 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
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 minimise 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
Minute Adjustment and Indication of Rotations
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.
SP-10MK2 and SP-10MK3 Compatibility
In order to enable
users to continue using the turntable base and tonearm of systems including the
SP-10MK2 and SP-10MK3, the shape and screw positions of the SP-10R base plate
are designed to allow mounting onto the SP-10MK2 and SP-10MK3 for complete backward
compatibility. The control unit is also the same shape and size as the SP-10MK2
power unit for trouble-free replacement.