SONY PS-X70

Commentary

This full-auto player system uses a dedicated motor for arm drive and logic circuit to solve the problems of full-auto.

In addition to normal full auto operation, auto operation of tone arm only or turntable only is possible.

We have adopted a record-end detection type Luminous sensor that does not apply lateral pressure to the needle tip. We also respond quickly to continuous operation instructions even in the event of an operation error. Through these measures, we have taken thorough measures to protect the needle tip.
In addition, when a force larger than the arm driving force is applied, the auto mechanism is separated so as not to put a burden on the mechanism.

It is equipped with a muting mechanism that reduces noise when the needle tip goes down or leaves the record board.

It is equipped with a simple linear BSL (slotless) motor that does not require a brush or slot in order to eliminate torque unevenness, which can be said to be the destiny of a DC motor. By eliminating the slot that causes cogging, torque unevenness is minimized and smooth and quiet rotation is realized.
In addition, 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 developed using precision measurement technology of the Sony Magne-scale. Magnetic material is coated on the inner wall of the outer circumference of the turntable with a wide rotating area, and 512 wave detection signals are magnetized. The average value of these signals is detected by a multi-gap head, and control commands are sent to the servo system.
Since this method has a high signal frequency of approximately 284 Hz at 33 1/3rpm, servo compensation can be performed up to relatively high frequencies of the 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 neck cylinder part, which is the joint part between the head shell and the arm pipe, holds the tip of the shell plug against the slope facing the bottom of the neck cylinder with a strong force due to the wedge effect. In addition, the locking nut is pushed forward by the reaction, and the root of the shell plug is tightened firmly from 4 directions.
As a result, two parts of the front and back are held in a ring shape by one operation, preventing mounting looseness.

The arm pipe is made of a special aluminum alloy with greatly increased rigidity, and by adopting a J-shape with high bending strength, rigidity approximately 8 times that of conventional aluminum pipe is obtained.
In addition, by adopting an integrated structure from the neck cylinder section to the bearing section, unnecessary joints are eliminated and resonance factors caused by joint looseness are eliminated.

The bearings use a Longs pan bearing shaft supported by a single straight shaft to prevent play caused by ball bearings. This minimizes movement at the operating point.
In addition, a tapered mirror finish of hardened cemented carbide with a diameter of 5 mm is used for the pivot shaft to improve contact with precision radial bearings and provide high rigidity support.

The SBMC is used for the cabinet because internal loss is larger than metal and the structure with high precision and strength can be easily obtained.

It uses a large insulator filled with gel-like high-viscoelastic material in a rubber cup.
The material filled in this insulator is very flexible, has high internal losses, and has moderate spring elasticity, which enables effective vibration absorption.
In addition, the height of this insulator can be adjusted to keep the cabinet horizontal, and the center of gravity is lowered to further improve stability.

Litz wire is used for parallel wiring inside the arm, and a low-capacity cord with gold-plated plug is used.

Model Rating

Type	Crystal Lock D. D. 2 motor full auto player system
<Turntable portion>
Turntable	32 cm Aluminum Die Cast 2.2 kg (Including Rubber Sheet)
Wow and flutter	0.025%wrms
Load characteristic	0% (Needle Pressure 230g)
Start-up characteristic	1/4 turn or less
Drift time	0.0003% / h or less
Signal-to-noise ratio	75dB(DIN-B)
Tone Arm Section
Effective length	235mm
Total Length	330mm
Arm Height Adjustment Range	+ / - 3 mm
Needle pressure adjustment range	0 ~ 2.5g (0.1g Interval)
Shell dead weight	11.0g(SH-155)
Usable cartridge weight limit (including shell weight)	11.0 ~ 19.5g 19.0g ~ 27.5g (Auxiliary Weight Used)
<General>
External dimensions	Width 480x Height 165x Depth 420 mm
Weight	Approx. 13 kg
Attachment	45 Rotation Adapter Auxiliary weight Head Shell (SH-155) Set of cartridge mounting screws