SANSUI XR-Q7II

Commentary

A full-auto quartz DD player with silent sync rotor and FF coreless motor.

In order to reduce the torsional vibration of the cabinet caused by the direct drive system, we have adopted an original silent sink rotor.
In the direct drive system, the motor of the drive source is located almost in the center of the cabinet housing, so the rotational force, which is the reaction of the motor drive, is generated in the cabinet. This is the same phenomenon that occurs when the helicopter starts rotating in the direction opposite to that of the rotor when it starts flying. In the helicopter, the rotation is suppressed by the small propeller at the rear of the helicopter.
This problem is not much of a problem if there is no torque fluctuation in the motor. However, in reality, torque fluctuation increases due to load fluctuation during record tracing in addition to torque fluctuation of the motor itself. As a reaction, torsional vibration in the rotating direction is generated in the cabinet, which shakes the arm base and affects sound quality.
In the silent sync rotor system, a sync rotor is mounted on the lower part of the system, which does not move when the motor is rotating constantly, but moves only to remove the reaction when there is torque fluctuation. This absorbs the reaction between the motors and reduces the rotational vibration level of the cabinet to less than 1/4, eliminating torsional vibration.

The drive motor is an FF (Friction Free) coreless motor that solves the problems of conventional coreless motors.
The stator of this motor is made of non-magnetic material, and the yoke rotor, which forms the magnetic circuit, is fixed to the spindle. Therefore, by rotating exactly in the same way as the rotor magnet, there is no suction force between the stator and the magnet, and no pressure other than the weight of the rotor is applied to the bearing.
Since the yoke rotor, which forms the magnetic circuit, rotates together with the magnet, ideal operation without magnetic hysteresis or eddy current is possible. In addition, smooth rotation is possible by adopting a linear drive system with sine wave that minimizes torque irregularities.
When the turntable is removed and the spindle is rotated by hand, this FF coreless motor rotates more smoothly and smoothly than conventional coreless motors.

The servo circuit uses a quartz-lock servo system, and the number of revolutions is detected by a turntable coated with 960 pole magnetic pulses on the inner circumference, achieving excellent rotational accuracy.

D. O. B. (Dynaoptimum Balanced) tone arm (optimum support point tone arm) is adopted for the tone arm.
This arm was developed by approaching the mechanism of vibration transmission from the angle of theoretical analysis of the position of the fulcrum. By placing the pivot axis on the dynamic fulcrum, vibration picked up from the needle tip is prevented from being transmitted to the pivot, and external vibration is prevented from being transmitted to the needle tip.
In addition, by adopting a brass arm pipe and an arm base made of zinc die cast, high rigidity is achieved.
The XR-Q7II is equipped with two straight arm pipes, which can be replaced according to the cartridge used and the height can be adjusted.

Equipped with a computer-controlled photoelectric detection type and contactless full auto mechanism.
This system has no adverse effect on the basic performance of the arm such as deterioration of initial motion sensitivity. In addition, it has a safety design to protect the needle tip, record, and auto mechanism. If the tone arm is intentionally stopped during auto operation or if there is a mechanical problem, all operations will stop after 20 seconds.

The cabinet is a wooden cabinet with a thick mirror finish using high-density material.

Polyester composite resin is used for the turntable sheet.

Model Rating

Type	Record player
Drive system	Electronically controlled direct drive
Motor	Quartz PLL servo FF coreless motor
Number of revolutions	33 1/3, 45 rpm
Turntable	33 cm aluminum die-cast, 1.7 kg
Wow flutter	0.009% or less (WRMS)
Signal-to-noise ratio	80 dB or more (DIN-B)
Start-up characteristic	1 second (120 °) at33 1/3rpm
Rotational speed deviation	± 0.002%
Temperature characteristic	0.00003% / ° C
Load characteristic	0%
Tone arm	Static balance type optimum support point system straight arm
Effective length	245mm
Overhang	16mm
Offset angle	22 °
Applicable Cartridge Dead Weight	4g ~ 9.5g
Height adjustment range	+ / - 3 mm
Full auto mechanism	Auto lead in Auto return Autorepeat With Manual Lifter
Rated power consumption	8W
External dimensions	Width 490x Height 192x Depth 430 mm
Weight	11.8kg
Attachment	Straight Type Replacement Arm