Pioneer PL-70LII

Commentary

This record player system is based on the concept of the PL-70 that directly addresses the essence of the player. It uses the latest technology for the tone arm and motor. It also features a silent lift-up function.

The arm is made of originally developed carbon graphite with high internal loss and high rigidity. By combining it with the base of high-purity aluminum pipe, it realizes a low-mass, high-rigidity arm that is resistant to resonance. In addition, the arm pipe is of a straight type that is advantageous in weight and provides high strength. In addition, the arm pipe is of a tapered shape that increases in second moment of area as it approaches the center of the arm. Thus, the rigidity is increased while reducing the low-mass. In addition, brass with high Young's modulus is used for the connector at the base of the arm to obtain sufficient strength.
The head shell is also made of a lightweight, highly rigid carbon fiber composite material. In addition to the excellent material, the shape is ribbed to increase the strength.

Vibration analysis theory is applied to determine the shape of the tone arm. In this method, the entire resonance of the arm is grasped in real time by a computer modal analyzer, the overall balance is controlled, and the vibration characteristics are made flat. In the measurement method, sensors are attached to each part of the tone arm, and the vibration distribution is expanded to about 1000 times the actual vibration displacement by a computer, and it is observed as an animation.

It employs a level variable oil braking system that realizes high sensitivity while suppressing harmful low-frequency resonance caused by warping or eccentricity of records.
Silicone oil is injected into the oil cup located at the upper part of the arm shaft, and the damping is applied by sinking the ring-shaped braking fin with the tip cut at 45 degrees. Since the amount of braking suitable for both vertical and horizontal directions can be applied at one point, the Q of low-frequency resonance is lowered. By this, the suppression of con-modulation distortion, which makes the reproduced sound muddy, is improved by 9 dB.
In addition, the brake oil uses silicon oil, which has less viscosity change with time and temperature. In addition, this silicon oil is stored in a high-precision molded oil cup to prevent oil bleeding and improve reliability.
The level adjustment ring of the level variable oil braking system is free when the scale is 0, and the braking amount increases as the scale increases from 1 to 5. This level adjustment ring uses a helicoid type with high precision lapping processing to prevent partial resonance.

The tone arm part adopts a mass concentration system in which the main weight is brought closer to the arm shaft and the equivalent mass of the needle tip is reduced. By reducing the moment of inertia of the tone arm, the basic performance before oil accuracy is also improved.

It employs a simple contactless end detection system using a Hall element and magnet, and a silent lift-up mechanism using a moving coil drive system arm elevation without any operating noise.
In addition, it is equipped with a pure electronic quick stop mechanism in which the arm gently rises when the performance ends and the turntable automatically stops.

In principle, the drive motor uses a coreless quartz PLL DC servo motor that does not cause cogging, which is the cause of uneven rotation. This motor uses a flat coil to generate a magnetic field instead of an air-core for the drive coil, thereby eliminating the strength and weakness of a partial magnetic field and preventing cogging.
In addition, the SH rotor (Stable Hanging Rotor) system has been adopted in order to improve the bare characteristics before the servo system. This system has a structure in which the rotor support point, which was previously located at the bottom of the motor, is moved just below the turntable. By this structure, the center of gravity of the turntable and the support point almost coincide with each other. In addition, the lateral pressure applied to the bearing, which is the heart of the rotating system, is reduced to improve the stability of the turntable.

The turntable uses a low-pressure casting method that is different from the conventional method. This is a hand-made method in which metal is slowly poured into an extremely precise mold and cooled naturally over a long period of time. Since the inside of the mold is kept uniform with less soot and bubbles, it achieves higher density and better dynamic balance than the conventional method.
In addition, in order to deaden the resonance of the turntable itself, a special anti-vibration material is applied to the back surface to prevent squealing which adversely affects the sound quality.

The cabinet is a 8.5 kg heavy weight cabinet designed by laminating conifer solid boards selected after trial manufacture and examination of various materials.
We have also adopted a newly developed low-center-of-gravity structure insulator with the center of gravity of the player system and the supporting point of the insulator at approximately the same height. As shown in the as shown in the structure diagram.

Low-capacitance oxygen-free copper wires and gold-plated terminals are used to minimize transmission loss at the tone arm leads, power cords and their contacts.

It is equipped with a 5 mm thick smoke door clear hood made by hand craft one by one as standard.

Uses a turntable sheet with excellent acoustic characteristics.

Equipped with S-shaped replacement arm pipe for easy replacement of head shell (with large weight)
In addition, carbon graphite shell integrated straight arm is also sold separately, and straight arm pipes are prepared for the number of cartridges to be used, and the cartridge can be easily replaced.

Model Rating

Type	Cartridgeless player system
Phono Motor Section
Motor	Coreless quartz PLL DC servo Hall motor
Drive system	Direct drive
Bearing structure	SH / rotor system
Turntable Diameter	31cm
Turntable inertia mass	480kg-cm2(including turntable seats)
Number of revolutions	33 1/3, 45 rpm
Rotational speed change	Electronic with short stroke switch
Uneven rotation	0.008% or Less (WRMS/FG Direct Reading Method) 0.018% or Less (WRMS/JIS)
S/N	85 dB or more (DIN-B) 68 dB or More (JIS)
Load variation	0% (Needle Pressure 300g or Less)
Start-up characteristic	1/3 turn or less
Starting torque	2kg-cm
Speed detection method	All-round integration method FG
Rotational speed deviation	Not more than 0.002%
Drift	Time drift : 0.00008% / h Temperature drift : 0.00003% / ° C.
Brake mechanism	Pure electronic
Tone Arm Section
Type	Variable oil braking system Pipe Arm with Static Balance Twin Pipe Exchange System
Effective length	282mm
Overhang	13.5mm
Tracking error	+ 1.2 °, -1.3 °
Needle pressure adjustment	Weight 1 rotation 1g
Applicable Cartridge Dead Weight	Straight : 3g ~ 14g S Shape : 6g ~ 32g (Including Shell)
Height adjustment range	+2 -4mm
Head shell	Carbon fiber composite material
<General>
Attachment mechanism	Quartz lock indicator Quick stop Silent lift up (electronic)
Semiconductors used	Quartz : 1 IC:10 Hall element : 3 LED:4 Transistor : 14 Diode : 6
Pwer	100 VAC, 50Hz/60Hz
Power consumption	20W
External dimensions	Width 550x Height 214x Depth 440 mm
Weight	21.5kg
Sold Separately	Shell-Integrated Straight Arm JP-516 (¥ 9,000)