Audio Database


Pioneer PL-70
150,000yen(around the 1980 time)

The high precision player system which realized the extraordinary stability by pursuit of the high precision, and gazed at the true nature of pre Ya to the extreme.

In the actuator, the nakedness property of the rotation before applying a servo itself was improved, and the extraordinary rotation precision is realized by developing and carrying SH and a rotor (Stable Hanging Rotor) scheme to it.
The unique structure which moved the supporting point of the rotor which suited the motor bottom until now to immediately under the turntable is used for SH and a rotor scheme, and it has succeeded in coinciding the centroid and the supporting point of a turntable mostly by this.
The motor shaft was fixed, the ball bearing was prepared on it, the structure contrary to the former of rotating a rotor has realized, and this has canceled carrying out an unstable reverse cone motion by congruential of the supporting point.
Moreover, in the motor, the high torque DC servo motor of 2 kg-cm which carries out the constant-speed rotation of the turntable of 31cm [ in diameter ] and inertial-mass 480 kg-cm2 within 1/3 rotation (about 1 second) is carried, and the outstanding stability is realized on it.

Different low voltage casting from the conventional turntable process is used for a turntable in order to acquire the rotation stabilized more and the outstanding acoustic feature.
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, and since there are few air bubbles etc. and the interior is kept uniform, it has realized the dynamic balance which is a high-density and was superior to the conventional scheme.
Moreover, in order to carry out the deadning of a turntable's own vibration, the special vibration proof agent was given to the rear view, and the resonance which has an ill effect on a tone quality is prevented.

Pioneer has adopted as the magnetic pole change (switching) organization of a motor the uncontacted change scheme by the hall device which developed the process uniquely.
Moreover, the high SN ratio is realized by making an actuator into SH and a rotor scheme by banishing the detailed noise generated between the motor shaft and the bearing until now, and also performing a special vibration proof manipulation to the interior of a phone motor unit.

The 1kg heavy weight class arm base which started brass Naked material one by one by handmade is adopted as the arm base. Furthermore, eight metals wings have adopted the chocking joint scheme which wraps the whole arm axis surface equally and binds it tight as the supporting part which fixes an arm axis.
Thereby, unlike the general type of mounting which carries out the screw stop of a Tip of the Day or several places, ガタ was banished and the occurrence of the partial vibration is prevented. Moreover, the chocking joint scheme is adopted also as the applied part of a head shell, and tone-quality investigation by thorough absent-resonance-izing is aimed at.

In order to realize a high sensitivity, controlling the low-pass vibration generated by the decentration which the record marketed has, or curvature, the newly developed level variable oil braking scheme is adopted.
Silicon oil is poured into the oil cup prepared in the arm bearing part, and this serves as a scheme with which the amount of braking for which it is a structure to which a dumping is applied and was perpendicularly and horizontally suitable, respectively by calming the braking fin of the shape of a ring which cut the leading end into 45 degrees is applied at a Tip of the Day. While reducing Q of a low-pass vibration by this, flat-ization of a mechanical impedance is realized.
The amount of braking also serves as a design which becomes large, and proper use with MC type to broad hi-compliance man-month type with thereby comparatively much low compliance type is possible for it as the tick mark of a level adjustment ring becomes large to a freelancer, and 1-5 in the location of 0. Moreover, the hericoid type which performed the high-precision wrapping manipulation was adopted as the level adjustment ring, and the partial vibration is prevented.

The main wait was brought close to an arm axis, the mass centralization system which reduced the equivalent mass of the needle point is adopted as a tone arm part, and the basic performance before applying oil braking is also raising it by making the moment of inertia of a tone arm reduce.
Moreover, full use of the high precision processing technology of Pioneer which is proud of micra order was made in the bearing part of the tone arm, and the stability support which stores the pivot in a pivot holder and is supported by a spring is adopted as it.
The tone arm serves as a long type design of 282mm of effective lengths who use a high-rigidity aluminum pipe, and has equipped standardly the head shell made from a carbon fiber of a low-mass and a high rigidity.

A 8.5kg heavy weight class cabinet is adopted as a cabinet. This cabinet serves as a firm design which carried out the four-layers laminating of the large needle-leaf tree solid board of a high rigidity, increased specific gravity, and an internal loss chosen after the trial production and the study with various materials.
Furthermore, the centroid of a player system 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 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 start stop button of a pure electronic formula is adopted.

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

The turntable sheet excellent in the acoustic feature is adopted.

Stream-composition SH
The Low

Rating of a mode
Form Cartridgeless player system
<Phone motor part>
Type name MU-70
Motor 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 0.009% or less (WRMS/FG Direct-reading method)
0.018% or less (WRMS/Japanese Industrial Standard)
S/N 78dB 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>
Type name PA-70
Form Good transformation oil braking scheme static balance S character type pipe arm
Effective length 282mm
Overhang 12.5mm
Tracking error + 1.8 degrees-1.1 degrees
Stylus-force coordination 1g (0.1g tick mark) of wait 1 rotations
Conformity cartridge self-weight 4g-24g (at the time of an attached shell using)
Height adjustable range ±3mm
Head shell 7.6g of carbon fiber head shell self-weights
An attached organization Quartz locking-in Decatur
Quick stop
The semiconductor used etc. Quartz crystal: One
Hall device: Three
Transistor: Nine
Diode: Four
Power source AC100V, 50Hz/60Hz
Power consumption 9W
Dimensions Width 550x height 214x depth of 440mm
Weight 23kg