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Witness the ultimate high-end integrated type CD player -- MDS++
type
D/A converter makes a good thing even better. Fully independent transport
and processor sections and EXT DSP connectors allow use of DG-38 for
sound field compensation. Optical and coaxial digital inputs and outputs
provide added flexibility. Fully digital control of CD mechanism achieves
optimization of servo parameters in real time.
The DP-67 is an integrated player dedicated to Compact Disc playback
with superb sound quality. It has inherited many technological features
originally developed for reproduction of new-generation formats such
as SACD. The DP-67 has been refined through extensive listening tests
and can also serve as a stand-alone digital processor. It lets you
discover untold riches of musical detail even in CDs with which you are
thoroughly familiar.
The processor section features an ultra-precise 24-bit D/A converter
using a newly developed MDS++
converter. This takes the MDS (Multiple
Delta Sigma) principle pioneered by Accuphase to new heights. It features
minimal distortion, excellent S/N ratio, superb linearity at low signal
levels, and outstanding performance in all other aspects. Since the DP-
67 provides access to this converter via a set
of two digital inputs (optical and coaxial), its
sound quality and performance can be utilized
also by external components capable of
supplying a digital signal. The benefits of
super-accurate D/A conversion will let any
digital signal sound its very best. A set of
digital outputs (optical and coaxial) is also
provided, allowing connection of a digital
recorder for formats such as CD-R, DAT, or
MD. This lets you record either the signal from
the internal CD transport or from an external source. In addition, the
EXT DSP connectors are convenient when wishing to use the Digital
Voicing Equalizer DG-28/DG-38 for sound field compensation in the
digital domain.
Spindle Motor
& Driver
Sled Motor
& Driver
Driver
RF
Signal
Processor EFM Decoder
& Error
Corrector Digital Audio
Data Encoder
Optical
Receiver
Pulse Amp
Pulse Amp Spindle
Servo
Controller
Focus &
Tracking Servo
Controller Clock
Generator
Key
MatrixInfrared
Receiver
From Remote
Commander Master
Control
Computer
Display
Driver
Balanced
Buffer
3-Pole
Linear Phase
Low-pass Filter
Balanced
Buffer
3-Pole
Linear Phase
Low-pass Filter
Digital Audio
Interface
DecoderOptical
Coaxial
Output
Input
Unbalanced
Output
Balanced
Output
Unbalanced
Output
Balanced
Output
EXT
DSP
Left
Digital
Inputs
Right
×4
MDS++ D/A Conversion
System
×4
MDS++ D/A Conversion
System
Optical
Head
Focus Coil
&
Tracking Coil
Tray Motor
& Driver
Disc Clamp
Motor & Driver
Optical
Transmitter
Coaxial
Transmitter
Optical
Coaxial Digital
Outputs
MS
dB Display
CD
ANALOG SECTIONDIGITAL SECTION
Driver Coaxial
Transmitter
Optical input display example
Coaxial input display example
DriverDriver
Driver
Balanced drive circuit
(no current flows in ground line)
Fully digital control of CD mechanism
Control of the mechanism section is fully digital, allowing the use of
adaptive circuits to optimize servo performance for each individual
disc. This assures enhanced operation stability and a drastic reduction
in error rate. Long-term reliability and performance uniformity are
also improved, since fluctuations in ambient temperature can have
no adverse influence.
Laser pickup with integrated RF amplifier
Since the output level of a laser pickup is very low, it is highly
vulnerable to externally induced noise. To prevent such problems,
the pickup used in the DP-67 employs an RF amplifier which is so
compact that it can be directly integrated in the pickup assembly.
This assures that the high-level output signal remains free from noise
interference, which in turn reduces the error rate.
Balanced drive circuitry for servo motors
The motors and actuators which drive the disc tray, spindle, sled,
and the focussing and tracking assembly require a rapidly fluctuating
drive current, which can affect other circuit areas and cause sound
quality degradation.
In the DP-67, the
drive current for
each actuator is
provided by two
amplifiers arranged
in a balanced
configuration.
Because there is no
circuit flowing in the
ground line, the
operation of other
circuits in the player remains entirely unaffected.
Tray lock prevents resonances
If the disc tray which is used to slide the disc into the unit resonates
due to vibrations generated in the rotating assembly while the disc
is playing, signal quality can be degraded. In the DP-67, the tray is
firmly secured during playback, to eliminate any possibility of harmful
resonances.
Power-on play and frame display
Power-on play means that the DP-67 can start playback when power
is turned on, allowing automatic playback in conjunction with an audio
timer. For precise location of any spot on a disc, the player can display
frame information (1 frame = 1/75 second), and functions such as
repeat can be carried out in steps of individual frames.
CD Transport Section Features and Functions
Digital Processor Section Features and Functions
MDS++
type D/A converter achieves
stunning performance and sound quality
Jitter-free high-performance digital
demodulator
3-pole linear phase analog filter with
outstanding phase characteristics
Digital level control with adjustment
range 0 dB to -“40 dB
Balanced and unbalanced analog outputs
Delta Sigma D/A converter
Digital demodulator IC
DP-67 Block DiagramCD actuator drive circuit
Drive signal
Load Load current
Conventional circuit
(current flows in ground line)
Drive signal Load current
Load
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I/V
I/V
-“
+
DAC 1
DAC 2
DAC 3
DAC 4
I/V
I/V DAC
#1
#2 S 1
e1
S2
e2
Sn-1
en-1
Sn
en
#n-1
#n
Digital inputSignal
Conversion error
S0 (Signal)
e0(Conversion error)
MDS output
Note the ratio between signal
and conversion error. In the
MDS output, the error is very
small in relation to the signal.(Normal phase output)
(Reverse phase output)
I (current)/V (voltage)
converter
Current summing Voltage summingSubtractionDAC output
MDS (Multiple Delta Sigma) is a revolutionary design which employs several delta sigma type converters in a
parallel configuration. In the combined output of these multiple converters, conversion errors cancel each other
out, resulting in a drastic improvement in all relevant aspects of converter performance: accuracy, S/N ratio,
dynamic range, linearity, THD, etc.
In the DP-67, four delta sigma type AD1955 converters made by Analog Devices are driven in parallel. This
results in an overall performance improvement by a factor of 2 (=
-ˆš4).
As shown in the diagram, the MDS++
features an enhanced current-to-voltage (I/V) converter for processing
the D/A converter output current. A combination of current summing and voltage summing is used, resulting in
even better stability and top-notch performance. When listening to a CD with this system, the music emerges
from a totally silent background. Breathtaking detail resolution and a highly accurate sound stage are immediately
apparent characteristics.
MDS++
D/A converter moves another step ahead
MDS type D/A converter principle
MDS++
converter block diagram
Assembly with
CD transport
control circuitry and
digital input/output
circuitry etc.Assembly with
MDS++
D/A
converter and
analog output
circuitry etc.
Supplied remote commander
RC-18
Offers a host of
functions such as
input switching,
direct play, program
play, repeat, etc.
