SONY SCD-1

Commentary

The first SACD player from Sony.

The SCD-1 is only for 2-channel stereo and does not support SACD multi-channel playback.

The servo circuit employs a signal processing servo system that performs optimal processing for both SACD and CD.
The servo control of the optical pickup and motor system differs greatly between SACD and CD. Therefore, the SCD-1 adopts digital servo using DSP to enable stable signal reading by performing optimum control for each of them. In addition, the signal read by the optical pickup is demodulated and error corrected by the RF processor. In the SCD-1, this process is also integrated into one chip, dedicated LSI for servo operation and RF signal processing, and achieves both high reliability and reduction of digital noise.

The DSD decoder LSI generates a 1-bit audio signal by decoding j-valued data recorded on SACD.
First, we decode the watermark, which is a feature of SACD, decode the data output from the RF processor, and output it as a 1-bit audio data stream according to an accurate clock. Since the quality of the 1-bit audio signal generated by this process has a significant effect on the final music signal output, we have developed and installed a DSD decoder LSI with high-precision processing capability. This DSD decoder LSI also decodes subcodes such as TOC (number of songs, playing time, text information).

The DSD signal of SACD expresses the music signal by the pulse density, and in order to maintain high accuracy, it is important how accurately the pulse is reproduced. The accuracy of this pulse reproduction is determined by the accuracy in the direction of the amplitude axis and the accuracy in the direction of the time axis. The SCD-1 is equipped with an ACP system and a current pulse D/A converter for accuracy in the direction of the amplitude axis, and an S-TACT pulse generator for accuracy in the direction of the time axis.

A newly developed ACP system (Accurate Complementary Pulse Density modulation System) is installed to eliminate the effect of switching distortion.
Ideally, the pulse signal should be a well-shaped square wave, but actually the pulse signal output from the IC does not have a vertical rise and fall, and it does not have an accurate shape due to the addition of overshoot and undershoot. This is the switching distortion that occurs when changing from 0 to 1 or 1 to 0.
In the ACP system, even 0 signals that do not normally output pulses are processed so that pulses are output, and the pulse widths of 1 and 0 are processed so that they have a complementary relationship with each other, so that the information of "presence / absence" of pulses is converted into information of "wide / narrow" of pulses, so that even if switching distortion occurs, it does not affect the accuracy of the DSD signal itself, making it possible to convert wide-band music signals into analog signals with high purity.

It is equipped with S-TACT (Syncronus Time Accuracy Controller) in order to improve the fluctuation of time base.
The pulse generator reads the input digital data and generates a highly accurate pulse signal. The pulse is generated using a high-purity clock with a quartz oscillator, and has extremely high time axis accuracy with quartz accuracy.
The S-TACT is equipped with a dedicated independent LSI, and the pulse generator is completely separated from digital arithmetic units such as digital filters and noise shapers. This eliminates adverse effects such as signal accuracy degradation due to power supply fluctuations caused by switching noise generated in the digital arithmetic unit, thereby enabling pulse generation with quartz accuracy.

The D/A converter is equipped with a current pulse D/A converter.
The DSD signal with improved switching distortion and time axis fluctuation by the ACP system and S-TACT is a high-precision voltage pulse, but in the case of a voltage pulse, the amplitude of the pulse may change subtly depending on the response at the time of switching.
The current pulse D/A converter has a stable constant current source inside, and is converted into a cleaner current pulse by switching the current source using a voltage pulse.

The current pulse output from the current pulse D/A converter is I-V converted, passed through an analog low-pass filter, and returned to an analog signal. This low-pass filter uses a GIC type filter. In this method, the signal does not pass through active elements such as semiconductors, so the sound quality can be maintained with higher purity.
SACD theoretically has frequency characteristics up to approximately 1.4 MHz. However, the actual reproduction frequency band is determined by taking into consideration the circuit design and component elements, and by selecting the best point in terms of sound quality. The SCD-1 low-pass filter has characteristics that attenuate gently from around 50 kHz, making it possible to reproduce signals over 100 kHz.

The digital filter used when playing CDs is equipped with a 24-bit variable (V. C.) digital filter.
This filter has more computing power than conventional filters. It has 24-bit accuracy and allows direct 8 x oversampling in a single operation. In addition, there are 5 filter positions where you can enjoy changing the sound.
Additional filter positions include the #1 Clear, which has been processed to make the signal smoother, and the #3 Fine position, Sony's first even-order filter.

A newly developed twin pickup has been adopted for the pickup section. It is equipped with a 650 nm wavelength pickup for SACD and a 780 nm wavelength pickup for CD. The reliability of signal reading is improved by installing an optimum wavelength pickup for each disc.
In addition, the optical system fixing mechanism is adopted for the signal reading method, and the pickup, which is easily affected by vibration, is fixed, and the heavy disk side is moved horizontally slowly. This reduces the fluctuation of the servo current controlling the pickup and enables stable signal reading.

Newly developed high-rigidity aluminum die-cast is used for the drive spindle motor.
A sapphire bearing is used for the support part and a ruby ball is used for the rotating part to reduce servo current by reducing rotational friction loss at the contact point.

The mechanical base is made of a machined aluminum material with a thickness of 6 mm, and a reinforcing plate with an opening to suppress unnecessary vibration is added to improve rigidity and prevent resonance.

It has a strong structure and adopts a top loading system that is resistant to vibration.
The loading panel adopts a newly developed electric loading mechanism that slides in the lateral direction. The guide rail for moving is not visible on the top panel surface, and the loading panel floats slightly and slides smoothly.
The internal structure is also equipped with a motor cover and floating mechanism to prevent noise and vibration. The inside of the housing where the disk rotates is also treated with anti-vibration paint. In addition, stainless steel is used for the main shaft of the slide mechanism, solid brass is used for the bearing, and steel plate of 1.6 mm thickness is used for the chassis base to increase rigidity.

BP chassis is used for the chassis structure.
This chassis has a simple structure consisting of a base chassis with two metal plates attached to it to a thickness of 10 mm and seven cast iron pillars to which side plates and top plates are attached. By increasing the strength of the constituent materials, the chassis has a simple structure with sufficient rigidity and a large space inside the chassis.
In addition, a high carbon material with good damping characteristics is used for cast iron that serves as a support to suppress resonance between the top plate and bottom plate.

A newly developed eccentric insulator is used for the leg part, and it has both features of point contact which eliminates turbidity in the middle and high range and surface contact which reproduces heavy low sound by supporting in the appropriate area.
This insulator has a pin-point structure inside a base made of high-carbon cast iron. The pin-point section is made of brass to disperse resonance caused by dissimilar metals, and the eccentric structure used in Sony's high-end audio equipment reduces vibration.

A glass-epoxy board is used for the audio board, and by adopting double-sided boards and bus bars, symmetrical layout and rational wiring are possible.
First of all, digital blocks such as S-TACT pulse generators, 24-bit variable digital filters, and D/A converters use surface mounting for the shortest distance data transmission and noise reduction. For the analog section after the analog low-pass filter, parts with excellent sound quality are selected and arranged in a loose layout. The output buffer amplifier is composed of discrete elements.
In addition, a discrete stabilized power supply for analog is placed on the audio board, and low-impedance power supply for each block is realized by independent 3-layer bus bars on the left and right sides. In addition, the ground line of the audio output terminal is mechanically connected directly to the audio board with a thick copper plate.
On the other hand, the main circuit board with a digital servo signal processing system is a surface mounted circuit board with a four layer pattern structure. It is a digital minimum circuit board that combines complex and large-scale circuits into a single small-area circuit board using LSI and small chips that are integrated into each block. This main circuit board is placed under the drive mechanism to enable transmission to the processing circuit at the shortest distance and to reduce unnecessary radiation noise.
With this layout, the power supply and audio circuit board with many large parts can be placed in the remaining part with allowance, and straighter signal path and power supply line construction are realized.

The power supply section is equipped with a dedicated power transformer for each of the audio and digital servo systems. The transformer uses an R-core transformer with a shield case filled with resin to reduce leakage flux and eliminate unnecessary vibration. In addition, it uses a remote-operated power switch to minimize the routing of the primary AC power line and minimize the contamination of power supply noise.
The audio power supply circuit employs a discrete method, which is advantageous in sound quality, and is placed on the audio board to supply power with low impedance. In addition, a stabilizing power supply is installed independently for each block, such as a digital filter or a D/A converter, to reduce interference in each part.

Equipped with a standard / custom changeover switch.
Conventional amplifiers and speakers are designed based on the characteristics of the CD frequency band up to around 20 kHz. For this reason, we have established a standard position to protect the amplifiers and speakers in case of insufficient conditions such as inadvertently increasing the volume when playing back SACD with ultra-high frequency characteristics.
The standard position is recommended when connecting to a conventional amplifier, and the custom mode is recommended when connecting to devices such as TA-E1 and TA-N1.

The SCD-1 can automatically determine the disk, but the determination time can be shortened by switching in advance with the disk selection key.
You can also choose to play each layer when playing a hybrid disc.

Both SACD and CD can display text data (alphanumeric characters) recorded in the text area.

Equipped with two digital outputs, coaxial and optical. Digital output is not available for SACD, but digital output is available for CD playback. Digital output can also be switched ON/OFF.

Equipped with a balanced output selection switch, balance output can be turned ON/OFF when unbalanced output is used.

Wireless remote control is included.
This remote control is a thin design with a clickable key switch and 1 mm thick aluminum plate.

Model Rating

Type	SACD player
Frequency characteristic	SACD: CD: 2 Hz to 100 kHz 2 Hz to 50 kHz -3dB 2 Hz to 20 kHz (EIAJ)
Dynamic range	SACD: CD: 105 dB or more 100 dB or more (EIAJ)
Total harmonic distortion factor	SACD: CD: Not more than 0.0012% 0.0017% or less (EIAJ)
Wow flutter	Below the measurement limit
Digital output	Optical : -18dBm Coaxial : 0.5Vp-p * Only when playing CD
Analog output	Unbalanced : 2 vrms Balance : 4 vrms * Fixed, with ON/OFF switch
Pwer	100 VAC, 50Hz/60Hz
Power consumption	30W
External dimensions	Width 430x Height 149x Depth 436 mm
Weight	Approx. 27 kg
Attachment	Wireless Remote Control RM-DS1 Stabilizer Power cable Audio connection cable Power plug conversion adapter

Position and outline of variable digital filter

Position	Cutoff characteristic	Sound impression
Sharp roll-off
Standard		It has the largest amount of information and is characterized by its wide range and spatial expression. Suitable for playing classical music.
Slow roll-off
No1 Clear		It a smooth touch and energy feeling, sound image localization is clear. Suitable for jazz band, jazz vocal, etc.
No2 Plain		It is fresh and energetic, and especially rich in expressive power of the luster of vocals. It is suitable for vocal music.
No3 Fine		It has a balanced natural sound with a sense of scale and rich reverberation. Perfect for enjoying a relaxed mood regardless of the genre of music.
No4 Silky		It combines a sense of scale and sensitivity. It is suitable for playing music that combines vocals such as opera and background music.