Audio Database

The

Pioneer PL-70LII
170,000yen(1981 release)

Description
 
The record player system which adopted the newest technology as the tone arm and the motor and also by which the silence lift up functionality also carried the thought of PL-70 which tackled the true nature of the player from the front as it is.

The internal loss has adopted as an arm material the carbon graphite developed uniquely as a large material with high rigidity, and the Low-Mass and the high rigidity arm are strongly realized to a vibration by combining with the base of the aluminum pipe of a high purity. Moreover, it is considering it as the taper form which a second moment of area increases as arm pipe form is advantageous in respect of weight, and has adopted the straight type with which a high intensity is obtained and also approaches focusing on an arm, and it is improving rigidity, measuring Low-Mass-ization. Furthermore, to the connector of the arm root fraction, sufficient intensity has been obtained using the large brass of a Young's modulus.
Moreover, a light weight and the carbon fibrous composite of a high rigidity are adopted also as a head shell, and, in addition to the merit of a material, the intensity is raised by attaching a rib to form.

Vibration analysis theory is applied to the determine of the form of a tone arm. With a computer modal analyzer, the whole vibration of an arm is grasped in real time, and this controls the whole balance, and makes an oscillation characteristic into a flat,A measurement technique attaches a sensor to each part of a tone arm, and by computer, an oscillating-component cloth is expanded to about 1000 times of actual oscillating displacement, and it is observing it as an animation.

The level variable oil braking scheme which a high sensitivity can realize is adopted controlling the harmful low-pass vibration generated by the curvature and decentration of a record.
Silicon oil is poured into the oil cup prepared in the arm axis upper portion, and this has a structure to which a dumping is applied by sinking the braking fin of the shape of a ring which cut the leading end into 45 degrees. Since the amount of braking for which it was perpendicularly and horizontally suitable, respectively is applied at a Tip of the Day, 9dB has improved to a suppression of the Cong modulation distortion which is reducing Q of a low-pass vibration and makes play sound muddy by this.
Moreover, the variation per hour and the viscous transition by a temperature have adopted little silicon oil, by storing in the oil cup which carried out high precision molding of this silicon oil further, it is considered as a structure without the blot leakage of oil, and the robustness is improved to braking oil.
It is the design to which the amount of braking also becomes large as the tick mark of the level adjustment ring of a level good transformation oil braking scheme becomes large to a freelancer, and 1-5 in the location of 0. The hericoid type which performed the high-precision wrapping manipulation is adopted as this level adjustment ring, and the partial vibration is prevented.

The tone arm part brought the main wait close to an arm axis, and the mass centralization system which reduced the equivalent mass of the needle point is used for it. By making the moment of inertia of a tone arm reduce, the basic performance before applying an oil precision is also raised.

No simple contacting and detection scheme with a hall device and a magnet, and the silence lift up organization by moving coil drive system arm elevation without a sound of operation are adopted.
Moreover, after a performance is completed, an arm goes up calmly, and the pure electronic quick stop organization which a turntable stops automatically is carried.

The cogging which causes rotation unevenness theoretically has adopted as the motor of an actuator the Quartz PLL DC servo motor of the coreless structure to generate [ no ]. By not using a core by using a drive coil as an empty core, but generating a magnetic field with a flat coil, this loses the strength of a partial magnetic field and has the structure where an cogging does not occur.
Furthermore, in order to improve the nakedness property before a servo, SH and a rotor (Stable Hanging Rotor) scheme are adopted. This has a structure which moved the supporting point of the rotor which suited the motor bottom until now to immediately under the turntable, and has succeeded in coinciding the centroid and the supporting point of a turntable mostly by this. Furthermore, the side pressure added to the bearing which is a heart of a rotation system is reduced, and the stability of the turntable is raised.

Different low voltage casting from the conventional process is adopted as a turntable. This poured in the metals slowly into the model molded very precisely, it is a handmade process which carries out a natural air cooling over many hours, there are few スs and air bubbles, and since the interior is kept uniform, it has realized the dynamic balance which excelled the conventional way in the high-density.
Moreover, in order to carry out the deadning of a turntable's own vibration, special vibration proof material was given to the rear view, and the resonance which has an ill effect on a tone quality is prevented.

The 8.5kg heavy weight class cabinet designed by laminating the needle-leaf tree solid board chosen after the trial production and the study with various materials is adopted as a cabinet.
Moreover, the centroid of a pre Iasi stem and the supporting point of the insulator were made into the almost same height, and the insulator of the newly developed low centroid structure supported by a spring as shown in a construction drawing is adopted as an insulator.

In order to suppress the transmit loss in the lead wire, the output codes, and those contacts of a tone arm to the minimum, the oxygen-free-high-conductivity-copper line of low capacity and the terminal of gilding are adopted.

The smoked acrylics hood of the 5mm thickness completed one by one by handcrafts is equipped standardly.

The turntable sheet excellent in the acoustic feature is adopted.

S character type switching arm pipe with an easy switching of a head shell is carried (with a large-sized wait).
Moreover, the shell integral-type straight arm of carbon graphite is also an option, and it is also possible only for the number of the cartridges to be used to arrange a straight arm pipe, and to carry out a cartridge switching simply.

The
Tone

Rating of a mode
Form Cartridgeless player system
<Phone motor part>
Motor Coreless Quartz PLL DC servo hall motor
Drive system Direct-drive
Bearing structure SH and a rotor scheme
Turntable diameter 31cm
Turntable inertial mass 480kg-cm2 (turntable sheet included)
Rotational frequency 33 1 / 3 or 45rpm
Rotational frequency change The electronic formula by a short stroke switchpoint
Rotation unevenness 0.008% or less (WRMS/FG Direct-reading method)
0.018% or less (WRMS/Japanese Industrial Standard)
S/N 85dB or more (DIN-B)
68dB or more (Japanese Industrial Standard)
Load variation 0% (less than 300g of stylus forces)
Startup property Less than 1/3 rotation
Starting torque 2kg-cm
Velocity detection scheme Perimeter integrator type FG
Rotational frequency deflection 0.002% or less
Drift Time drift : 0.00008%/h
Temperature drift : 0.00003%/degree C
Braking mechanism Pure electronic formula
<Tone arm part>
Form Good transformation oil braking scheme
Static balance twin pipe exchange system pipe arm
Effective length 282mm
Overhang 13.5mm
Tracking error + 1.2 degrees-1.3 degrees
Stylus-force coordination 1g of wait 1 rotations
Conformity cartridge self-weight Straight: 3g - 14g
S character type: 6g - 32g (shell lump)
Height adjustable range +2 -4mm
Head shell Carbon fiber composite material
<Synthesis>
An attached organization Quartz locking-in Decatur
Quick stop
Silence lift up (electronic formula)
The semiconductor used etc. Quartz crystal: One
IC:10
Hall device: Three
LED:4
Transistor: 14
Diode: Six
Power source AC100V, 50Hz/60Hz
Power consumption 20W
Dimensions Width 550x height 214x depth of 440mm
Weight 21.5kg
Option Shell integral-type straight arm JP-516 (9,000yen)