DENON DP-5000F
¥ 78,000 (released in July 1974)
Commentary
Turntable with improved reliability and usability based on DP 5000.
The rotational speed is detected by applying a magnetic coating on the inside of the turntable with a material with a large coercive force, and using a magnetic head to detect 2000 pulse signals recorded with an accuracy of 1/10000 pulse interval error.
With this method, at a speed of 33 1/3 rpm, the frequency of the pulse to be detected is approximately 1100 Hz. This frequency is more than 10 times that of other methods, and the time constant of the integration circuit in the frequency-voltage conversion circuit can be greatly reduced. Therefore, the phase delay of the servo loop in the high frequency range can be reduced, and stable servo can be applied even if the loop gain is increased.
The detected voltage is compared with the reference voltage, and the motor drive voltage is controlled by the voltage difference for servo control.
The turntable has a weight of 1.1 kg and a moment of inertia of 160 kg ・ cm.2Lightweight turntables are used to reduce the bearing load and maintain stable performance over a long period of time.
The servo circuit has a high loop gain, sufficient temperature compensation, and a built-in DC stabilized power supply. As a result, stable rotation is achieved even when the power supply frequency or voltage changes, temperature changes, needle pressure, or other load conditions change.
The drive section uses a solid rotor type AC servo motor with smooth rotation. Compared with other synchronous motors and DC motors, this motor has smooth rotation characteristics with less vibration. In addition, it is driven by AC with beautifully shaped waveform to reduce rumble.
The speed fine adjustment selection button can be adjusted by ± 6% in a variable state.
A light emitting diode is used for the power supply lamp.
Model Rating
Type | Turntable |
Drive system | Servo-operated direct drive |
Motor | Solid rotor type 2-phase torque motor |
Speed control | Servo by frequency detection |
Number of revolutions | 33 1/3, 45 rpm |
Speed switching mechanism | Electrical switching |
Startup time | 1.2 seconds (1/3 rotation, 33 1/3rpm) |
Wow and flutter | Less than or equal to 0.025% wrms (according to test records) |
Motorboard | Aluminum die cast |
Signal-to-noise ratio | 60 dB or more |
Turntable | 30 cm aluminum die-cast, 1.1 kg |
Moment of inertia | 160 kg / cm2 |
Rotational speed adjustment range | Variable : + / - 6% |
Pwer | 100 VAC, 50Hz/60Hz |
External dimensions | Body Part : Width 370x Height 139x Depth 374 mm Radiator : 270 mm wide x 49 mm high x 70 mm deep |
Weight | 6.8kg |