SONY PS-P7X

Commentary

This auto return player system was developed as a line up of micro component PRECISE and realized the size of one and a half LP jacket and 110 mm height.

The motor is equipped with a linear BSL (slotless) motor.
By eliminating the slots that cause cogging, torque unevenness is minimized and smooth and quiet rotation is realized. Moreover, high torque is obtained due to high efficiency, and reliability and durability are also improved.

The velocity detection section of the servo system employs a Magne-disk velocity detection method. In this method, the inner wall of the outer circumference of the turntable, which has a wide rotating area, is coated with magnetic material. The detection signal of 512 waves is magnetized. The average value of the detection signal is detected by a multi-gap head, and control commands are sent to the servo system. In addition, since the generated signal has a high frequency of approximately 284 Hz at 33 1/3rpm, servo compensation can be performed up to relatively high frequencies among flutter components.

Magnedisk A crystal lock is adopted by adding a phase control circuit of crystal oscillation to the detected speed servo circuit. By phase locking the detected signal, not only initial drift due to self-heat generation of the body, but also rotational speed deviation due to voltage fluctuation due to self-heat generation and rotational speed decrease due to needle pressure load are reduced, and excellent rotational characteristics are obtained.

The SBMC is used for the cabinet, which has higher internal loss compared to metal and can easily obtain a structure with high precision and strength. In addition, the low center of gravity structure insulator with adjustable height is used for the insulator, and the rubber cup inside is filled with gel-like high viscoelastic material to enable effective vibration absorption.

The auto-return mechanism is equipped with a servo motor with FG for arm drive to improve reliability. It is also equipped with a muting mechanism to prevent touch noise to the record of the needle tip.
It also uses an electronic record-end detection Luminous sensor that does not apply lateral pressure to the needle tip.

Up / down of the tone arm, start / stop of the motor, and number of revolutions can all be done by front operation.

LED display of rotational speed is possible.

The cartridge is equipped with MM type cartridge XL-25A.

Model Rating

Type	Crystal Lock D. D. 2 Motor Auto Return Player System
<Turntable portion>
Turntable	31 cm Aluminum Die Cast
Wow and flutter	0.025%wrms
Signal-to-noise ratio	75dB(DIN-B)
Tone Arm Section
Effective length	216.5mm
Total Length	300mm
Needle pressure adjustment range	0 ~ 3g
Usable cartridge weight limit (including shell weight)	12g ~ 18.5g 18g ~ 24.5g (Auxiliary Weight Used)
Cartridge Section
Cartridge	MM Type (XL-25A)
Frequency characteristic	10 Hz to 30 kHz
Output voltage	4 mv (1 khz, 5cm/s, 45 °)
Needle	0.3x0.8 mil Oval Diamond Needle
Dead weight	5.2g
<General>
External dimensions	Width 430x Height 110x Depth 350 mm
Weight	9.5kg
Attachment	45 Rotation Adapter Auxiliary weight Head shell Cartridge (XL-25A)