SONY PS-4750
¥ 53,800 (around 1974)
Commentary
A direct-drive player system that uses SBMC and magne-disk servo systems.
It employs a magnesium-disk servo system developed with the technology of Sony Magnesscale, a specialized manufacturer of precision measuring instruments such as data recorders and acoustic records.
In the Magnedisk system, a signal of 512 waves is magnetized in a wide range around the periphery of the turntable, and the average value of the signal is detected by an 8-tooth multi-gap head, which enables highly accurate and stable detection.
In addition, the servo response range has been greatly expanded to improve the servo effect and achieve good load characteristics and wow / flutter characteristics.
A sucker type insulation mat is used to suppress resonance by making the record adhere to the turntable.
This mat has a small hole in the center of the suction cup, and the viscous resistance of the air passing through this hole reduces unnecessary longitudinal vibration and dampens resonance.
As a result, the signal in the longitudinal direction of the groove of the record is related to the stereo effect, so the effect of improving the orientation is obtained, and the modulation noise is removed to suppress the turbidity of the sound.
SBMC, a new material developed by Sony engineers, is used for the cabinet and turntable.
This material is a thermosetting reinforced resin that combines polyester resin with calcium carbonate and glass fiber. It has a shrinkage rate of 2 to 3/10,000, which is almost equal to 0. Therefore, it is difficult to be deformed after shaping and high-precision processing is possible. In addition, since the specific gravity can be freely adjusted, the specific gravity can be set to obtain the optimum moment of inertia.
In addition, since the internal loss is larger than that of aluminum, resonance is difficult, and howling and S/N are improved.
Equipped with independent pitch control for each of 2 speeds of 33 1/3 and 45 rpm, precise speed adjustment is possible.
Universal type static balanced arm with replaceable shell is adopted.
In addition, an inside for scan seller is built into the body, and it is equipped with an overhang checker.
The cartridge tilt adjustment mechanism allows adjustment so that the needle tip is perpendicular to the record.
The cartridge is equipped with a MM type cartridge in which a small circular magnet is placed in a V-shape.
0.5 mil diamond needle is used.
Equipped with an arm lifter that is linked to a power switch.
Uses a large rubber insulator.
Model Rating
Type | Record player system |
<Turntable portion> | |
Turntable | 34 cmSMBC, 1.0 kg |
Motor | DC servo motor |
Drive system | Direct drive |
Number of revolutions | 33 1/3, 45 rpm |
Speed adjustment range | + / - 4 per cent |
Start-up characteristic | Within 1/2 Rotation (33 1/3rpm) |
Wow flutter | 0.03%WRMS |
Signal-to-noise ratio | 70dB(DIN-B) |
Tone Arm Section | |
Tone arm | Static balance S-shaped universal tone arm |
Effective length | 237mm |
Total Length | 314mm |
Overhang | 15mm |
Tracking error angle | + 2 ° 30', -1 ° 20' |
Offset Angle | 21 ゜ 30' |
Needle pressure adjustment range | 0 ~ 3g |
Shell Weight | 7.5g |
Usable cartridge weight | 4g ~ 14g |
Cartridge tilt adjustment range | ± 12 ° |
Cartridge Section | |
Cartridge | MM Type |
Frequency characteristic | 10 Hz to 30 kHz |
Separation | 25dB(1kHz) |
Output voltage | 3 mv (1 khz, 5cm/s) |
Optimum load impedance | 47k Ω ~ 100k Ω |
Compliance | 10x10-6Cm / dyne (vertical, horizontal) |
Needle pressure (optimum needle pressure) | 1.5g ~ 2.5g (2g) |
Needle | 0.5 mil diamond needle |
Weight | 5.5g |
Exchange needle | ND-134G |
<General> | |
Semiconductor used | IC : 1 Transistor : 6 Diode : 5 pcs |
Power supply voltage | 100 VAC, 50Hz/60Hz |
Power consumption | 5W |
External dimensions | Width 477x Height 175x Depth 420 mm |
Weight | 8.5kg |
Attachment | 45 Rotation Adapter Phonocode |
Sold Separately | Sony Oil OL-2KA Cartridge XL35, XL-45 |