17
DVD Technical Notes
Construction
The same insistence on high-performance parts that marks the
video section of the DVP-S9000ES can be found throughout the
audio section, as befits a fully qualified member of Sony’s ES
Series. The parts are selected after undergoing exhaustive
testing. For example, the audio circuit board is a glass epoxy
design that steadfastly resists deformation. The copper foil
traces on the circuit board are twice the normal thickness.
Principal parts are secured with through-hole connections. The
digital circuit is intentionally compact with the shortest practical
leads. High quality electrolytic capacitors are used wherever
they can impact sound. Even the AC power line uses gold
plating for the minimum in contact resistance. The result is
remarkably pure, superbly clean sound.
Vibration is the enemy of DVD 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 DVP-S9000ES
takes advantage of Sony’s comprehensive anti-resonant design.
It’s one more way the player reflects its dual heritage as a top
Sony DVD machine and proud member of the ES Series.
The first line of defense against vibration is Sony’s Frame and
Beam (FB) chassis. In this design, the thick, high-strength
chassis frame gains additional strength from a horizontal beam.
The back panel and main parts use 1.6 mm thick sheet metal
while the bottom plate is 2 mm thick. The chassis corners
benefit from stiffening boards that add strength and diffuse the
natural resonant frequencies. In this way, materials of different
shapes and thicknesses combine to suppress vibration. In
addition, copper plating on the back panel and bottom help
reduce noise by decreasing the ground potential difference.
To prevent shelf-borne vibration from entering the chassis, Sony’s
insulator feet locate the screw hole off center. Varying the radius
from screw to perimeter tends to vary the resonant frequency
within the foot — diffusing one potential path for vibration.
The DVP-S9000ES marks the debut of an all-new drive mechanism
of unusual design. On a conventional DVD drive, the spindle,
drive motor and optical pickup are mounted on a pivoting base
unit. The pivot is necessary because the base unit needs to drop
out of the way when the disc drawer is opening and closing. And
it needs to swing back up into playing position once a disc has
been loaded. Unfortunately, this pivoting mechanism is an open
invitation to vibration and resonance.
Sony engineers
demanded more.
And they developed
the fixed base unit
mechanism. In the
new Sony design,
the spindle, motor
and optical pickup
base unit is rigidly
bolted to a sub-
chassis, to reduce
any possibility of
resonance. When you load a disc into the DVP-S9000ES, the
disc not only moves laterally into the player, it also descends
onto the spindle. Thanks to Sony’s new design, the disc is
always read in a silent, extremely stable non-resonant
environment. Vibration is minimized, along the servo activity
vibration can cause. The sensitive RF preamplifier is protected
from servo radiation.
When it carries the disc down to the fixed base unit, the loading
tray no longer acts like a door to seal the front-panel loading slot.
Sony engineers addressed this by creating a hermetic shutter. It
forms an airtight seal to protect the disc and pickup from airborne
vibration. Even when the speakers in your room are going full
blast, the disc rotates in peace and quiet.
Audiophile Parts
Build Right
Copper-Plated Frame and Beam Chassis
Photo 6: Sony’s copper-plated Frame and Beam (FB) is not only strong. Parts of different
shapes and thicknesses combine to suppress resonance.
Off Center Insulator Feet
New Fixed Base Unit Mechanism
Fig. 20: Conventional DVD players use a pivoting base unit
(top), prone to vibration. The Sony DVP-S9000ES uses a
rigidly fixed base unit (bottom), minimizing vibration and
its consequent distortion.
Hermetic Shutter
