16
purity. A straight path carries the signal directly from the D/A
converter input to the output terminals on the back panel. As an
added precaution, extra-thick low-impedance jumper cables
eliminate patterning between the main ground of the audio board
and the main ground of the digital block.
Power transformer cores and windings can vibrate and degrade
the sound, radiating 60 Hz hum into nearby audio circuits.
That’s why Sony shields the audio circuit board. And that’s why
Sony chose twin R-Core power transformers. 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. The core itself is formed from long
narrow magnetic steel plates, rolled into shape without gaps that
might also generate hum. To further protect the audio stage from
interference, one transformer handles video, system control
and servo systems while the other specializes in audio
alone.
While switching power supplies are common in DVD players,
Sony demanded more. We use more traditional series power
supplies with the twin transformers followed by rectifiers.
Separate power supply secondaries are employed for each stage.
And the secondaries are located on the circuit boards they serve:
audio, video, system, motor drive and display. In addition,
separate regulation is used in the D/A converter, VC 24 Plus,
master clock oscillator and digital output buffer blocks. This
minimizes even slight opportunities for mutual interference
through the power supply.
27 MHz. For a further reduction in noise, the power supply to
any unused clocks is automatically turned off.
One potential concern with so many types of circuitry in one
chassis is mutual interference. Sony minimizes the possibility of
radiated interference with Audio Direct output, a front panel
switch that automatically shuts off all Video and Digital outputs.
The switch enables the DVP-S9000ES to operate audio-only
whenever you desire. Three other power configurations are also
offered:
• Video Off. Shuts down the video and power circuitry to
eliminate its effect on the audio circuitry.
• Digital Off. Shuts down the signal.
• Display Off. Cuts off power to the fluorescent display panel,
for a further reduction in noise.
The DVP-S9000ES is capable of sending out DVD-Video sound
tracks at full 96 kHz/24-bit resolution on discs without copy
protection. (Discs with copy protection are limited to 48 kHz/
16-bit digital outputs.) To support full 96 kHz/24-bit digital
output, the optical output module operates all the way up to 13.2
Mbps. So you can connect with maximum fidelity.
As an added safeguard to signal integrity, the digital output
signal is re-synchronized immediately before the coaxial and
optical digital outputs. The signal is realigned to the highly
accurate master clock at 49 MHz (for DVD-Audio) and 45 MHz
(for CD and SACD). This reduces the possibility of distortion-
inducing jitter at the digital outputs.
As a further defense against radiated noise, the audio circuitry is
isolated on its own circuit board, shielded by 1.6 mm sheet metal
and fed by its own, dedicated power supply secondary, located
on the circuit board itself. The board is laid out in classic dual
monaural configuration, for enhanced stereo separation and sonic
Audio Direct Output ( for all discs )
Jitter-Free 96 kHz / 24-bit Digital Output
Separate Audio Circuit Board ( for all discs )
Twin R-Core Power Transformers ( for all discs )
Power Supply Configuration ( for all discs )
Photo 5: Sony minimizes power transformer hum and
noise by incorporating two carefully made R-core power
transformers.
Fig. 19: Contrary to common practice, the DVP-S9000ES subdivides the audio master
clock for video, not the other way around.
Photo 4: The front and back of the audio circuit board reveal
DVD Technical Notes
Audio
