Sony SCD-XA9000ES SACD Player - Page 6

Construction & Design

- Discrete Dual Laser Optical Pick Up

The SCD-XA9000ES can play back SA-CD, CD, CD-R and CD-RW discs. There is substantial difference in the laser wavelength of SA-CD (650 nm) and CD (780 nm). Sony accommodates that difference with the discrete dual laser optical pickup. This system has two independent lasers working through a common lens. One laser handles CD, CD-R and CD-RW while the other achieves uncompromised reproduction of SA-CD.

The system requires a beam splitter, a special objective lens that can handle both wavelengths and dual focus. This results in substantially lower mass than systems with completely separate optical blocks. Lower mass reduces servo currents, for a corresponding reduction in noise radiated into the sensitive preamplifier stage. Lower mass also means faster track access, for greater operating convenience.

- Twin R Core Transformers

The video and control circuits can introduce noise to the power supply voltage, which can trigger audio distortions. To protect the audio circuitry, the player uses two separate power transformers: one for the servo and digital system and another just for audio. In addition, power supply regulation on the audio circuit board itself helps establish stable operation for the audio D/A converters.

Power transformer cores and windings can vibrate and degrade the sound, radiating 60 Hz hum into nearby audio circuits. That's why Sony chose an R-Core design. The R stands for round. Not only is the core round, it has a cylindrical cross section, enabling the transformer windings to be wrapped without the voids or gaps that permit vibration. This results in far less radiation, far less hum. These two transformers are mounted on a copper plate, which is quite effective in reducing vibration. The audio power supply circuit also incorporates discrete components, including electrolytic capacitors, carefully selected for their sound quality.

The two power transformers have round cores with cylindrical cross
sections. This enables far more consistent transformer windings—for
far less radiated hum.

- Frame and Beam (FB) chassis

Vibration is the enemy of CD and Super Audio CD players for two powerful reasons. First, vibration in the disc or optical pickup triggers unwanted operation in the tracking servos. This can radiate spurious noise throughout the chassis. And this radiation occurs in exactly the wrong place—near the sensitive, low-level optical pickup preamplifier. To make matters worse, vibration can also cause subtle distortions in the audio circuitry. Vibration can have tiny "microphonic" effects on capacitor values and point-to-point wiring. While these distortions are not always apparent to the casual listener, Sony's design program required performance without compromise. For all these reasons, the SCD-XA9000ES incorporates Sony's anti-resonant Frame and Beam (FB) chassis.

In the SCD-XA9000ES, Sony's Frame and Beam (FB) chassis uses a thick, high-strength frame which gains additional rigidity from two broad metal girders or beams that cross the chassis from front to back. For even greater rigidity, the juncture where the beams meet the chassis front is reinforced by triangle braces. To further suppress resonant modes, Sony engineers selected metal members of different shapes and sizes to cancel unwanted vibration.

Front view (left) and side view (right) of Sony's Frame and Beam (FB) chassis. It's supremely strong to suppress resonance.

The two beams have the added function of supporting the player's mechanical drive unit. Unfortunately, the two beams never have exactly the same length. This means that the mechanical block can exert slightly different tension on the beams, potentially exciting different vibration modes and generating unwanted chassis resonance. To combat this resonance, Sony engineers decoupled the beams from the rear panel. The beams connect to a rigid metal frame, which is connected to the rear panel. This design restricts the potential for whole-chassis vibration.

Schematic view of the chassis design, showing the chassis beams (light
blue), mechanical drive unit (violet) and audio circuit boards (orange).

- Silver Cascade Design

In addition to its remarkable technology, the SCD-XA9000ES inaugurates a new faceplate design exclusive to the Sony ES Series. The "cascade" design sets all the primary front panel controls at an angle, so that you can operate the front panel without uncomfortable bending and stooping to identify each control. The silver colored faceplate is made of brushed aluminum and fits in beautifully with conventional audio components. But the design really comes into its own when the SCD-XA9000ES is combined with other silver cascade components, such as the STR-DA9000ES.

The STR-DA9000ES shows how the Silver Cascade design extends to
receivers. The design is also featured on the STR-DA5000ES and
DA3000ES.