Technics SP-15 - User Manual

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Summary

Before Use and Setup

Assembly and Setup Procedure

Steps for assembling the turntable, possibly with an optional base.

Connections and Placement

AC Power and Ground Connections

Details on connecting the AC power plug and ground wire to the amplifier.

Optimal Unit Placement

Recommendations for placing the turntable for stable, vibration-free operation.

Operating the Turntable

Power and Speed Control

Instructions on setting the power switch, pitch lock, and speed selection.

Pitch Control Functionality

Details on fine-tuning turntable speed using the pitch control.

Maintenance and Safety Guidelines

Power Source Safety

Precautions regarding correct voltage and avoiding direct current.

Power Cord Handling

Safe practices for handling the power cord and plug to prevent shock.

General Safety Suggestions

Verify Power Source Voltage

Ensure the unit is connected to the correct power source voltage.

The Technics SP-15 is a QUARTZ Synthesizer Direct Drive Turntable designed for high-fidelity audio playback. This device is engineered to provide precise and stable rotation for an optimal listening experience, incorporating advanced features for both performance and user convenience.

Function Description

The primary function of the Technics SP-15 is to accurately spin vinyl records at precise speeds, allowing a tonearm and cartridge (not included with the turntable unit itself) to extract audio information from the record grooves. It utilizes a direct-drive system, meaning the motor directly drives the platter, eliminating the need for belts and reducing potential speed fluctuations.

A key feature is its QUARTZ Synthesizer system, which provides a highly stable and accurate rotation speed. This system ensures that the turntable maintains its set speed with exceptional precision, unaffected by temperature changes or power fluctuations. The quartz lock mechanism is designed to prevent accidental changes to speed or pitch control settings during playback, ensuring uninterrupted performance.

The turntable is equipped with a powerful high-torque motor, enabling it to reach constant playback speed very quickly (0.4 seconds at 33-1/3 rpm). This rapid start-up is complemented by a double braking system, combining electronic and mechanical brakes, which allows the platter to stop almost instantly (0.4 seconds at 33-1/3 rpm) when the stop button is pressed. This quick start and stop capability enhances user convenience, especially in professional or broadcast environments where rapid cueing is often required.

The SP-15 also features a sophisticated pitch control system. Unlike conventional turntables where quartz lock might be disengaged for pitch adjustments, the SP-15 maintains quartz lock even during pitch control operations. This allows for fine adjustments of the turntable speed in precise 0.1% increments over a wide range (±9.9%), all while maintaining the stability of the quartz synthesizer. This capability is particularly useful for musicians who need to tune instruments to a record, or for DJs who require precise beat matching. The pitch variations are clearly indicated by a digital LED display, providing accurate visual feedback to the user.

To minimize external vibrations and resonance, the SP-15 incorporates several design elements. The oversized turntable platter is made of aluminum die-cast and features a special viscoelastic damping material applied to its underside and outer periphery. This material, combined with a rubber turntable mat, effectively absorbs vibrations and eliminates turntable resonance, contributing to a cleaner sound reproduction. The unit's cabinet is also constructed from a strong, precision aluminum die-cast material, further enhancing its vibration damping capabilities and minimizing susceptibility to acoustic feedback.

The electronic circuits of the SP-15 are highly integrated, utilizing over 3,000 discrete elements concentrated into four custom ICs. These include a Synthesizer pitch control CMOS LSI, Frequency dividing IC, phase speed control IC, and Driving IC, all working together to achieve high precision and stable operation.

For power, the SP-15 employs a highly efficient pulse power supply circuit. This circuit obtains DC voltage by oscillating at a high frequency (20 kHz) and rectifying the AC power supply, which prevents leakage of commercial power source frequency into the audio signal.

Usage Features

Operating the Technics SP-15 is designed to be straightforward and intuitive. To begin, the user places a record on the turntable mat and presses the start-stop button. The platter quickly accelerates to the selected speed. Speed selection is managed by dedicated buttons, allowing the user to choose between 33-1/3, 45, and 78.26 rpm, accommodating various record formats. The current speed and pitch adjustment percentage are displayed on a digital indicator.

The pitch control function is activated when the power switch/pitch lock knob is set to "on." Pitch adjustments are made using "+" and "-" buttons, with each press changing the speed by 0.1%. A "clear" button is provided to instantly reset the pitch to the normal playing speed (0.0% variation). For situations where pitch adjustments are not desired, or to prevent accidental changes, the power switch/pitch lock knob can be set to "pitch lock." In this mode, both the pitch control and speed select buttons are locked, ensuring that the turntable maintains its set speed without interruption.

Placement of the unit is crucial for optimal performance. It should be positioned on a stable, horizontal surface with minimal vibration, and as far away from speakers as possible to isolate it from sound radiation. The unit should also be kept away from direct sunlight, dust, moisture, heat, and in a well-ventilated area to ensure longevity and consistent performance. Interference with AM radio reception may occur if a radio is placed too close to the turntable during operation.

Connecting the SP-15 involves plugging the AC power cord into a wall socket and connecting the ground wire (GND) to the "GND" terminal of an amplifier or receiver. A firm ground connection is essential to prevent "HUM" noise from the power source.

For users building their own base or cabinet, the manual provides guidance on material thickness and stability, recommending durable and heavy materials and stable insulators. An optional turntable base, Technics SH-15B1, is available and designed specifically for the SP-15, simplifying installation.

Maintenance Features

Maintenance for the Technics SP-15 is minimal but important for ensuring long-term performance and safety. The unit should be wiped with a soft, dry cloth. Harsh cleaners containing alcohol, benzene, or thinner, as well as chemical dust cloths, should be avoided as they can damage the finish.

Lubrication of the motor shaft is recommended after every 2000 hours of operation, which is a significantly longer interval than conventional motors. Technics original oil (Part number SFWO 010) should be used for this purpose.

Care should be taken when handling the turntable platter, as a magnet is attached to its underside. It's important to prevent dust or iron filings from adhering to the magnet and to avoid dropping the platter from a height, which could damage the magnet. If the platter needs to be removed, the power plug should be disconnected first. The screws on the underside of the turntable platter and motor portion should not be removed, as loosening them can compromise the unit's rated performance.

Safety guidelines are emphasized throughout the manual. Users are advised to avoid exposing the unit to water or humidity, and to prevent foreign objects or liquids from entering the unit. It is crucial to connect the unit only to the specified voltage and to avoid using it with wet hands. The power cord should be handled carefully, never pulled to disconnect, and kept free from sharp bends, pinching, or crushing.

The unit should not be placed near heating equipment, as excessive heat can cause deformation of plastic parts or damage the cabinet, potentially leading to fire. Special care should be taken in homes with children to prevent them from inserting small objects into the unit's ventilation holes, which could cause electric shock or malfunction.

In case of water spills or any malfunction, the power cord should be immediately disconnected, and the unit should be serviced by a qualified technician. Users are strongly advised against attempting to remodel, reconstruct, or repair the unit themselves, as this could lead to electric shock or other accidents. After use, it is important to ensure the power is off to prevent damage to the unit and potential hazards.