SANSUI FR-D4K

Commentary

A DD player with a built-in computer full auto mechanism.

Computer LSI is used for the electronic circuit of the full auto mechanism.
In this system, an arm position sensor and a lifter position sensor composed of LED and phototransistor are provided in the mechanism section, and the arm and arm lifter are controlled by computer LSI by inputting these sensors. During full-auto operation, the position of the arm and arm lifter, record size setting, repeat, etc. are repeatedly checked through these sensors, and the next signal is output to enable quick and accurate operation.
The end groove counts the time between one pulse of the arm position sensor with a pulse counter, and reads even a slight difference of 33 and 45 rpm. When the set time and pulse width are confirmed, the arm is judged to be running in the end groove of the record and the end operation is started. When the repeat instruction is given, the arm is carried to the set point of the record which can be detected by the arm position sensor, and the arm does not return to the arm rest but lead-in.
This mechanism is designed to give priority to stopping. It immediately enters the stop operation at any position of the full auto, so there is no worry of damaging the needle of the cartridge.

The full-auto mechanism is equipped with a special motor to enable accurate operation.
In addition, the arm and the mechanism are separated by a disk clutch, so it is designed to be contact-free so that it is not affected by the mechanism during tracing.

The Dynaoptimum Balanced arm is used for the tone arm. In this method, in addition to the conventional mass concentration method, the optimum support point theory is adopted. The pivot position of the arm is set to the optimum position for dynamic balance. This prevents vibration of the pivot part from being transmitted to the cartridge and at the same time prevents unnecessary vibration from the needle tip from being transmitted to the pivot part, making excellent tracing possible.

The turntable drive motor is equipped with a 20-pole 30-slot VG servo motor.

Switches are installed on the front and all operations are possible with the dust cover closed.

Uses cartridges made by Empire.

It has a strobe on the front for better visibility with bright lighting.

The cabinet uses a silver metallic cabinet that is resistant to howling, and the legs use newly developed insulators.

Uses a turntable sheet with good record adhesion.

Uses a new type of acrylic dust cover.

Equipped with a pivot protection mechanism, even if the arm is locked to the arm rest and started by mistake, the safety device will work after 20 seconds and stop the automatic operation.
In addition, the special spring protects the pivot of the arm from damage even when the arm is locked to the arm rest.

Model Rating

Type	Record player
<Turntable portion>
Drive system	Electronically controlled direct drive system
Motor	DC brushless servo motor (VG servo)
Number of revolutions	33 1/3, 45 rpm
Speed adjustment range	+ / - 3%
Turntable	300 mm Aluminum Alloy Die-cast
Wow flutter	0.028% or less (WRMS)
Signal-to-noise ratio	72 dB or more (DIN-B)
Tone Arm Section
Tone arm	Optimum support point system static balance S-shaped type 2 Point Pivot Support
Effective length	220mm
Overhang	17.5mm
Applicable Cartridge Dead Weight	4g ~ 10g
Cartridge Section
Cartridge	MI Type (EP-10 manufactured by Empire)
Frequency characteristic	20 Hz to 20 kHz
Output voltage	4.5 mv (1 khz, 35.4mm/sec, 47k Ω)
Proper needle pressure	1.5g ~ 2.5g
Needle tip	0.7 mil Diamond Needle (ES-10)
<General>
Power consumption	9W or less
External dimensions	Width 440x Height 133x Depth 385 mm
Weight	6.3kg