SONY PS-8750
¥ 168,000 (around 1975)
Commentary
A direct-drive player system that employs a crystal lock system and magnedisk servo.
In order to solve the problem of rotational speed accuracy, a crystal lock servomechanism is adopted.
Unlike conventional servo circuits, a phase control circuit for crystal oscillation is added to the magne-disk speed control circuit. This circuit has features such as small changes in rotational speed due to ambient temperature and aging, and is not affected by fluctuations in power supply voltage, frequency, and load.
The servo motor uses a Magne-disk servo system based on the technology of the Sony Magne-scale precision measuring instrument. The turntable is magnetized with 512 wave signals over a wide area around the circumference. The 8-tooth multi-gap head detects the average value of these signals, making it possible to detect them with high accuracy and stability.
In addition, since the servo response range is greatly expanded, the servo effect is improved, and good load characteristics and wow / flutter characteristics are obtained.
Using an electronic brake, the brake is applied not only during stop operation, but also when switching from 45 rpm to 33 1/3rpm, and it quickly enters into steady rotation.
Since it is an electronic brake, there is no excessive burden on the mechanism.
Speed switching by pitch control is possible.
Since the crystal lock effect is large, the pitch control operation is performed by removing the crystal lock.
The turntable uses die-cast aluminum of precision processing with deadening, and it has the effect of reducing resonance sharpness.
In addition, an oil dump type insulation mat is used for the turntable seat, which is a special liquid with high viscous resistance enclosed in soft rubber to suppress the vibration and resonance of the phonograph record.
It uses a purely electronic non-contact detection auto return, reducing the contact resistance of the mechanism and making the movement of the arm smooth.
The cabinet uses a newly developed SBMC by Sony.
This SBMC is a thermosetting reinforcing resin that combines a polyester resin base with calcium carbonate and glass fiber. It is 1.5 to 2 times stronger than wood (lauan plywood) and has less than one third the resonance sharpness (Q) of aluminum die-cast.
By using this material, howling is suppressed and the SN ratio is improved.
The tone arm uses a static balance S-shaped universal tone arm.
A carbon pipe arm is used for the arm pipe part. By annealing the carbon fiber with direction to obtain rigidity, the rigidity is increased and resonance resistance characteristics are obtained. In addition, the arm support part is equipped with a 2-point type release bearing using jewel with high sensitivity, lateral balancer, inside for scan celler, gold plated connector, etc.
The arm lifter is a remote type.
The head shell uses SH-160, a carbon-clad shell. This head shell is made by laminating carbon fiber on aluminum material, and suppresses resonance of the head shell called shell squeal, and makes the reproduction sound clear.
A special insulator with high vibration absorption rate is used for the leg part of the player case.
Equipped with touch-feeling start / stop and reject switches.
Dust cover with anti-static treatment is included.
Model Rating
| Type | Record player system |
| <Turntable portion> | |
| Turntable | 32 cm Aluminum Die Cast |
| Motor | AC servo motor |
| Drive system | Direct drive, crystal lock system |
| Number of revolutions | 33 1/3, 45 rpm |
| Speed adjustment range | ± 4% (Crystal Off) |
| Start-up characteristic | Within 1/2 Rotation (33 1/3rpm) |
| Wow flutter | 0.025%WRMS |
| Signal-to-noise ratio | 70dB(DIN-B) |
| Initial drift | Crystal on : 0.0005% or less Crystal off : 0.1% or less |
| Load Characteristics (Needle Pressure 3g) | Crystal on : 0% With crystal off : 0.05% or less |
| Velocity deviation | Crystal on : 0.003% or less Crystal Off : Variable |
| Tone Arm Section | |
| Tone arm | Static balance S-shaped tone arm |
| Effective length | 237mm |
| Total Length | 320mm |
| Overhang | 15mm |
| Tracking error | Within ± 2 ° |
| Needle pressure adjustment range | 0 ~ 2.5g (0.25 steps) |
| Arm Height Adjustment Range | 7mm |
| Shell Weight | 12.5g(SH-160) |
| Usable cartridge weight (when using the attached shell) |
3g ~ 10g 8g ~ 14g (Auxiliary Weight Used) 13.5g ~ 19.5g (Auxiliary Weight Used) |
| <General> | |
| Semiconductor used | IC : 8 Transistor : 49 Diode : 36 units |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 20W |
| External dimensions | Width 458x Height 184x Depth 395 mm |
| Weight | 14.2kg |
| Attachment | 45 Rotation Adapter Spacer (For Cartridge Height Adjustment) Cartridge mounting screws 4 types Arm Lifter Height Adjustment Driver Tracking error confirmation gauge Auxiliary Weight (2 types) Shell (SH-160) Phono cord (low capacity) |
| Sold Separately | Shell SH-150H, SH-160 Cartridge XL-35, XL-45 |