Technics SP-15
¥ 100,000 (around 1979)
Commentary
A quartz synthesizer type direct drive turntable that inherits the technology of SL-1300mk2 and allows selection of 597 quartz lock pitches.
597 different quartz pitch controls are available for 3 speeds of 33 1/3, 45, and 78.26 rpm up to ± 9.9% in increments of 0.1%.
Equipped with a with a high torque heteropole D. D. motor and realizes a starting torque of 3 kg ・ cm. It can rotate a large heavy duty turntable weighing 2.7 kg at a constant speed in 0.4 seconds (33 1/3r. p. m time).
In addition, the turntable stops in 0.4 seconds by combining the electronic brake and the mechanical brake.
Based on the vibration analysis of the turntable, deadening is applied to the back surface of the turntable with a special viscoelastic material. This deadening is applied to the back surface and outer circumference of the turntable. In addition, the rubber sheet on the top surface of the turntable is inserted into the turntable to form a three layer deadening, which suppresses the resonance of the turntable and prevents howling by blocking, absorbing and thoroughly absorbing external vibration.
The cabinet is made of aluminum die-cast, which has high processing accuracy and is resistant to changes in the external environment. The bottom base is made of double anti-vibration structure using TNRC, which has excellent anti-vibration and damping characteristics.
CMOS LSI (MN6042) for synthesizer pitch control. I2High-integration ICs are used for complex electronic circuits with a total of more than 3,000 elements. For example, DN860 is used for frequency division ICs using L and ECL, AN660 is used for phase speed control ICs, and AN640 is used for driving ICs.
Equipped with a unique D. D. motor that integrates the rotating part of the motor and the turntable.
Full-circumference detection F. G is used to detect the rotational speed of the motor.
Equipped with a pitch lock mechanism that locks the number of pitches specified by speed switching and pitch control.
A high-efficiency pulse power supply circuit is used for the D. C power supply circuit.
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Model Rating
| Type | Quartz Synthesizer D. D. Turntable |
| Drive system | Direct drive |
| Drive motor | Brushless DC motor |
| Control system | Quartz phase locked control |
| Turntable | Aluminum Die-cast, Diameter 33.9 cm, 2.7 kg (Including Rubber Sheet) |
| Moment of inertia | 380 kg / cm2(Including Rubber Sheet) |
| Number of revolutions | 33 1/3, 45, 78.26 rpm |
| Fine tuning of rotational speed | 0.1% step, adjustable to ± 9.9% (digital display9) |
| Starting torque | 3 kg / cm |
| Start-up characteristic | Constant speed in 0.4 seconds (at 33 1/3rpm) |
| Outage time | 0.4 seconds (at 33 1/3rpm) |
| Brake mechanism | Electronic brake and mechanical brake |
| Load variation | Within 2.5 kg / cm 0% |
| Rotational speed deviation | Within ± 0.002% |
| Wow flutter | 0.025%WRMS(JIS C5521) ± 0.035% peak (IEC98A, weighted) |
| SN ratio (rumble) | 78dB(IEC98A weighted) 56dB(IEC98A unweighted) |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 9.5W |
| External dimensions | Width 349x Height 93x Depth 372 mm |
| Weight | 6.2kg |