Pioneer PL-470
¥ 44,800 (around 1980)
Commentary
A full auto player that uses an SH rotor type coreless motor.
PL 470 is a full auto player that can perform auto lead in, Oatley turn, auto cut and auto repeat without touching the tone arm.
An SH rotor type coreless motor is used as the drive motor.
In the SH-rotor system, the rotor support point, which used to be located at the bottom of the motor, is moved just below the turntable so that the center of gravity of the turntable almost coincides with the support point. This eliminates from the root the reverse cone motion and the rotational slippage caused by the lubricating oil used between the shaft and the bearing. In addition, the bare nature of the motor before the servo was applied is improved, and the rotation of the turntable is stabilized. In addition, parts such as shafts and bearings are also improved in accuracy of micron order or less by utilizing Pioneer's precision processing technology, and reliability and durability are improved.
The SH rotor type coreless motor realizes smooth rotational torque without cogging by using a coreless structure in which a driving coil is an empty core and a flat coil is used to generate a magnetic field without using a core. In addition, the diameter of the coil for generating the magnetic field is increased, a thin flat coil is used for the coil, and the power efficiency required for torque generation is improved by using Pioneer's original new IC, and high torque is realized.
The servo circuit uses a quartz PLL system that controls the phase difference by comparing the reference signal of the crystal oscillator with the speed detection signal of the motor.
In order to improve the accuracy and reliability of the PL 470, a sample-and-hold type high-gain F-V converter, which is highly stable against ripple (erroneous signal), has been developed as a single-chip IC, and is used in the frequency control circuit and phase control circuit.
The speed detection mechanism of the motor itself uses an all-round integration method. In this method, the AC signal obtained by the pole magnetized at equal intervals over the whole circumference of the lower surface of the rotor magnet and the print pattern coil with the same number of poles attached opposite to each other is integrated over the whole circumference to improve reliability. In addition, a special large magnet is used, and by doubling the magnetized magnetic pulse from the conventional 200 pole to 400 pole, it is possible to quickly apply servo against load fluctuation, and dynamic load characteristics are greatly improved.
We have also adopted a brushless motor pole switching circuit that uses a Hall element developed by Pioneer.
A straight arm using carbon graphite is adopted for the tone arm.
This arm realizes high rigidity, low mass and no resonance by forming carbon graphite into a straight pipe with high mechanical stability and combining it with aluminum base.
Carbon fiber composite material is used for the head shell to increase strength and reduce weight.
High-purity oxygen-free copper wires are used in the signal transmission system to improve sound quality.
The cartridge is equipped with a high power MC cartridge that can be used in the MM position.
This cartridge uses Pioneer's independently developed 6-pole 4-magnet configuration for the left and right sides. Samarium-cobalt magnets with high energy product (BHmax) are placed opposite to each other in the same pole. As a result, a high magnetic flux of up to 10,000 Gauss can be obtained, and power is efficiently generated linearly from small amplitude to large amplitude. In addition, as the left and right sides are independently generated, there is essentially no interference between channels, and excellent separation characteristics are obtained.
In this MC cartridge, the magnetic circuit and needle are separated and independent, so the needle exchange can be done as easily as MM type.
The cabinet uses a coaxial suspension.
In this system, the motor and tone arm are fixed to a single underboard, and the whole underboard is spring supported, preventing harmful resonance and suppressing howling.
The operation buttons are all front operation type located on the front panel for improved operability.
Equipped with a quick play mechanism that starts rotating the turntable when the tone arm is moved onto the record board, and with a quick stop climate that stops rotating when the tone arm is returned to the arm rest.
Since the arm lifter is operated by a dedicated DC motor during manual operation, smooth and highly reliable elevation operation is possible.
The exterior is finished in champagne gold.
.JPG)
Model Rating
| Type | Record player |
| Phono Motor Section | |
| Motor | Coreless quartz PLL DC servo hole motor |
| Bearing system | SH / rotor system |
| Starting torque | 1.3kg-cm |
| Drive system | Direct drive |
| Turntable | 32 cm Aluminum Die Cast |
| Number of revolutions | 33 1/3, 45 rpm |
| Uneven rotation | 0.012% or Less (WRMS, FG Direct Reading Method) 0.025% or Less (WRMS, JIS) |
| S/N | 78 dB or more (DIN-B) 65 dB or More (JIS) |
| Start-up characteristic | 1/3 turn or less |
| Starting torque | 1.3 kg / cm |
| Rotational speed deviation | 0.002% or less |
| Drift | Time drift : not more than 0.00008% / h Temperature drift : 0.00003% / ℃ or less |
| Tone Arm Section | |
| Type | Static balance straight arm |
| Effective length | 221mm |
| Overhang | 15.5mm |
| Applicable Cartridge Dead Weight | 3g ~ 8g (Excluding Head Shell) |
| Head shell | Made of carbon fiber |
| Cartridge Section | |
| Type | MC Type |
| Needle tip | 0.5 mil round diamond needle |
| Exchange needle | PN-3MC |
| Output voltage | 2.5 mv (1 khz, 50mm/sec. horizontal) |
| Load resistance | 30k Ω ~ 100k Ω |
| Appropriate load resistance and load capacity | 50k Ω · 170 pF ~ 300 pF |
| Proper needle pressure | 2g ± 0.3g |
| Frequency characteristic | 10 Hz to 32 kHz |
| Dead weight | 3.1g |
| <Others> | |
| Attachment mechanism | Auto lead in Auto return Autocut Autorepeat Quick play Quick stop Anti-skating Arm elevation Arm height adjustment mechanism Needle pressure direct reading weight Connector type head shell |
| Semiconductors used | ICx4 Transistor x7 6 diodes 2 Hall elements LEDx10 Crystal x1 |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 8W |
| External dimensions | Width 420x Height 114x Depth 395 mm Dust Cover Fully Open : Width 420x Height 383x Depth 430 mm |
| Weight | 6.5kg |