Pioneer XL-1551
¥ 63,000 (around 1977)
Commentary
A record player that added a quick stop mechanism to the XL 1550.
The XL-1551 has a quick stop (brake) mechanism.
Turning the control lever to OFF stops the turntable and allows quick change to the next record.
In addition, the exterior is finished with metallic star tone.
Quartz PLL system is adopted for servo circuit.
In this method, the phase difference is detected by comparing pulses from a power generator attached to the motor's rotating shaft with pulses from a crystal oscillator to maintain the motor's rotational speed.
In order to improve the reliability of the circuit itself, we have been making efforts to convert it into an IC. Bipolar ICs are used for the drive circuit and MOS ICs are used for the control circuit.
A bi-directional a bi-directional drive circuit that operates in the forward and reverse directions. As a result, even when the motor speed increases, the electric brake is applied in the reverse direction, enabling quick response. As a result, even when the rotational speed is changed, constant speed rotation is achieved immediately.
High-precision control circuits, high-torque direct drive motors, precision-machined shafts, bearings, turntables, and other devices provide excellent performance.
The strobe uses an easy-to-adjust single-stripe strobe and a waveform circuit that makes it easy to see the stripes.
Conventional speed adjustment strobes generally use the frequency of a home AC power supply for irradiation. For this reason, four stripes are required for each power supply frequency and rotation speed. On top of that, general power supplies for prizes have a frequency fluctuation of about 0.1%, making it difficult to make precise adjustments.
The XL XL-1551, the oscillation frequency of the crystal oscillator (3 MHz band) is divided by an electronic circuit and is turned on to eliminate the influence of fluctuations in the power supply frequency. In addition, the frequency division ratio (33 1/3rpm : 55.5 Hz, 45 rpm : 75 Hz) can be changed when the rotation speed is changed to enable adjustment with one stripe.
In addition, since the flash current is pulse-lit by the waveform shaping circuit, the flash inscribed on the turntable periphery can be clearly read.
The servo circuit has a built-in CR oscillator, so that even when the quartz is turned off, the PLL (phase control) works, and excellent load resistance and drift characteristics can be obtained even during fine adjustment.
The drive motor uses a high-torque brushless DC servo hole motor with a diameter of 32.4 cm and inertial mass of 340 kg ・ cm.2Rotate the large aluminum die-cast turntable at a constant speed within 2/3 revolutions. The starting torque of this motor is 1kg-cm.
The switching mechanism uses three independently developed Hall elements to achieve high S/N and durability.
S-shaped pipe arm is used for the tone arm.
In addition to reducing the effective mass of this arm, a high-precision angular contact bearing is used for the vertical and horizontal rotating parts to reduce friction and obtain high sensitivity.
In addition, a 6t aluminum panel is used for the arm mounting base, and steel plate (thickness 6 mm, weight 700g) is reinforced from the inside of the cabinet to protect the tone arm from howling during ultra-low frequency reproduction.
The head shell uses a non-resonant type made of aluminum alloy to reduce the weight.
The MM type PC 330 / II cartridge is used.
The cantilever of this cartridge is made of titanium pipe with special heat treatment. It is light at 0.45 mg and has little deflection, so it keeps the mechanical impedance low and increases the tracing capability.
The cabinet uses a combination of particle boards.
Equipped with an arm height adjustment mechanism that can be adjusted at a height of ± 5 mm from the reference position.
Equipped with an anti-skating mechanism.
Butyl rubber is used for the turntable seat.
Uses an insulator that combines special rubber and die-cast solid.
The level of this insulator can be adjusted, and it can be changed by 0.5 mm per one rotation of the insulator.
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Model Rating
| Type | Quartz PLL Direct Drive Player |
| <Turntable portion> | |
| Motor | Quartz PLL hole motor |
| Drive system | Direct drive |
| Turntable | 32.4 cm Diameter Aluminum Die Cast |
| Turntable inertia mass | 340kg-cm2 |
| Number of revolutions | 33 1/3, 45 rpm |
| Speed change | Electronic |
| Rotational speed fine adjustment range | + / - 6 per cent |
| Uneven rotation | 0.025% or less (WRMS) |
| S/N | 62dB(JIS) 70dB(DIN-B) |
| Load variation | 0% (Needle Pressure 120g or Less) |
| Start-up characteristic | 2/3 turn or less |
| Rotational speed deviation | Not more than 0.003% |
| Temperature drift | 0.00004% / ℃ or less |
| Time drift | 0.0003% / h or less |
| Tone Arm Section | |
| Format | Static balance S-shaped pipe arm |
| Effective arm length | 221mm |
| Overhang | 15.5mm |
| Applicable Cartridge Dead Weight | 4g ~ 14.5g (Sub Weight Over 9.5g is used) |
| Height adjustment range | + / - 5 mm |
| Cartridge Part> | |
| Format | MM Type (PC-330/II) |
| Structure | Shield Case : Super Permalloy Frame : Die Cast Aluminum Alloy |
| Needle tip | 0.5 mil diamond |
| Effective mass of vibration system | 0.45mg |
| Operating needle pressure range | 1.0g ~ 1.8g (1.5g appropriate) |
| Frequency characteristic | 10 Hz to 28 kHz ± 3 dB |
| Channel separation | 25 dB or More (1 kHz) 20 dB or More (100 Hz to 10 kHz) |
| Output voltage | 3 mv (1 khz, 50mm/sec, RMS) |
| Output balance | Within 1 dB (1 kHz) |
| Dynamic Compliance | 12x10cm-6/ dyne (100 Hz, horizontal / vertical) |
| Static Compliance | 18x10cm-6/ dyne (optical) |
| Output impedance | 2k Ω (1 kHz) |
| Load resistance | 30k Ω ~ 250k Ω (Proper 47k Ω + 170 pf) |
| Dead weight | 6.4g |
| Dimensions | Width 14.8x Height 17x Depth 290 mm |
| Mounting Dimensions | JIS and EIA standards |
| Exchange needle | PN-330/II |
| <Others> | |
| Attachment mechanism | Anti-skating mechanism Lateral balancer Needle pressure direct reading weight Arm height adjustment mechanism Quick stop mechanism Arm elevation mechanism Head Shell Stand (Common Use for EP Adapter Receiver) Strobe light lamp Free stop hinge Height Adjustable Insulator |
| Supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 5W |
| External dimensions | Width 490x Height 185x Depth 390 mm |
| Weight | 12kg |