DENON DP-40F

Commentary

This is a player system that pursues ease of use by adopting a new mechanism for the direct drive player.

The newly developed electronically controlled servo tone arm is used for the tone arm.
By turning the position selector (location knob) on the front panel, the dedicated MC-type angular control motor set at the base of the arm is servocontrol and the arm can be moved smoothly.
Moreover, since the arm is contact-free, there is no loss of sensitivity of the arm, and even if the arm is touched while moving, there is no effect.

The position selector uses a 2-point contact type touch sensor switch.
When you touch the knob for cue, the arm leaves the rest and moves onto the record board. When you turn the knob to position the needle tip of the cartridge, release the hand. If the lifter is pushed, the arm goes down and the turntable rotates to start playing.
If you want to listen to it again during the performance, touch the knob again. The arm automatically rises and returns to the position indicated by the position selector again to start the performance.
If the repeat switch is set to ON, it automatically returns from the end of the record to the beginning and starts playing without returning to the arm rest.

The horizontal movement of the auto arm is performed while maintaining the optimum speed with the servocontrol. Up is performed quickly with the dedicated motor and down is performed slowly with the oil brake.
The newly developed MC-type angular control motor for driving the arm consists of a fixed magnet and a movable coil directly connected to the rotating shaft of the arm. The rotating shaft is driven by the current flowing in the coil, and it is contact-free. Therefore, it does not give unnecessary load to the arm and is not affected by external magnetic field.
The rotation angle of the arm is detected by the combination of the LED, CDs, and a polarizing plate placed between them. One polarizing plate is attached to the rotation axis of the arm, and the other two polarizing plates are fixed with a polarization angle of 90 degrees each. When the arm moves from the outer circumference to the inner circumference of the record, the polarizing plate rotates, the amount of light incident on the CDs changes, and the position of the arm becomes the rotation angle signal.
The position selector emits a signal corresponding to an arbitrary position on the record board, and the arm moves until this signal matches the arm rotation angle signal.
The speed at which the arm moves is servocontrol to a constant speed. The rotation angle detection signal of the arm is proportional to the change in the rotation angle, but the rate of change is also detected by the servo circuit and is always controlled to a constant speed.

Anti-skating controls the torque of the MC type angular control motor and cancels the inside force.

At the innermost circumference of the record, the arm's rapid movement is simultaneously detected by the arm position and lead-out (derived groove), and the dedicated motor for the arm lifter operates.

A unique magnetic recording detection rotational speed servo system has been adopted for the turntable drive unit, taking advantage of the quartz lock system.
The magnetic recording detection type speed servo detects 1,000 pulses magnetically recorded at an extremely accurate pitch inside the rim of the turntable. The detection accuracy is high and the response is fast. It is highly effective against warping and disturbance of records.

The newly developed high-cost performance AC servo motor is used as the drive motor.

Newly developed turntable seat is adopted.
This turntable sheet was developed based on vibration analysis by laser holographic interference.

Model Rating

Type	Full auto player
Phono Motor Section
Drive system	Servo system direct drive
Drive motor	AC servo motor
Speed control system	Speed servo and phase servo by frequency detection
Number of revolutions	33 1/3, 45 rpm
Speed switching mechanism	Push-button type
Wow flutter	0.015% Wrms or less
Signal-to-noise ratio	75 dB or more (DIN-B)
Startup time	Within 1.5 seconds (33 1/3 o'clock)
Load characteristic	0% (Needle Pressure 80g, Outermost Circumference)
Power supply voltage characteristics	0% for variations from 90 v to 110 v
Rotational speed deviation	0.002% or less
Turntable	30 cm Aluminum Die-cast
Moment of inertia	200 kg / cm2(including turntable seats)
Arm Section
Type	Static Balance S-Shaped / Universal
Auto mechanism	Electronically controlled servocontrol system
Effective length	244mm
Overhang	14mm
Needle pressure adjustment range	0 ~ 2.5g
Applicable Cartridge Dead Weight	15g ~ 21g (Including Shell)
Head shell	High Impact Molded Aluminum Alloy, Viscoelastic Material Included, Approx. 9g
Head connector	EIA standard 4-pole connector
Output code	Low capacity cord, approx. 1.2m
<General>
Cabinet	New Grand Mahogany Wood Finish Particle Board
Pwer	100 VAC, 50Hz/60Hz
Power consumption	14W
External dimensions	Width 485x Height 146x Depth 437 mm
Weight	Approx. 12 kg