Accuphase DP 65 Brochure

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Accuphase DP 65 Brochure

Extracted text from Accuphase DP 65 Brochure (Ocr-read)


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Ever since the birth of the CD, technical
progress has been advancing at an amaz—
ing rate, Some manufacturers invest con-
siderable efforts in making CD players more
affordable, while others worked hard to
achieve better sound. Accuphase always
was a forerunner in the field of sonic
advancement, as demonstrated by the 20-
Bit Discrete D/A Converter, the introduction
of optical signal transmission, the elimina—
tion of digital interference, and many other
breakthroughs. As a case in point, the
separate—type CD reproduction system con—
sisting of the Transport DP—90 and Proces-
sor 00-91 has been widely acknowledged
as redefining the art of digital audio. The
MMB (Multiple Multi-Bit) D/A converter
developed for the DC~91 offers sonic resolu-
tion that is nothing short of amazing, thanks
to a no-holds-barred design with 16 strictly
selected 20-bit converters connected in
parallel. With its outstanding linearity and
virtual absence of residual noise, this con—
verter type represents the pinnacle of the
multl—bit principle.

The DP—65 is an integrated CD player that
has inherited many of the technological
innovations championed by the DP-QO/DC-
91 combination. In sound quality, it comes
astonishingly close to those stunning per-
formers. One of the guiding principles dur-
ing the development of the DP-65 was the
pursuit of peerless 20-bit performance. lts
D/A converter is an MMB type with four
strictly selected 20-bit elements connected
in parallel, to assure ideal digital-to-analog
conversion characteristics. Linearity of
analog output versus digital signal input is
excellent over the entire dynamic range,
from very high to extremely low signal
levels. Distortion and noise are virtually
absent.

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Linearity (digital Input vs. analog output)

The mechanical side of the DP-65 also has
a lotto offer. The laser pickup assembly is
designed with an integrated, ultra-compact
RF amplifier which makes the output signal
much less prone to noise and interference.
This contributes to a notably reduced error
rate. The motors and actuators for moving
parts such as the disc tray, spindle, sled, as
well as the focussing and tracking assem—
bly are driven by balanced circuitw where
no current flows in the ground line. Current
fluctuations therefore cannot enter the sig-

MMB type D/ A converter approaching l
Complemented by high-quality 20-bit, 8
filter and GIC 3-pole analog Butterwori
40 MBit/s optocoupler assures thoroug
Massive, solid chassis and tray-lock mei

nal path and adversely affect the sound.
The locking tray design maintains a firm
hold of the tray during playback, to prevent
harmful vibrations and resonances. The
entire CD mechanism is mounted on a
massive metal chassis that offers high
rigidity and effectively absorbs vibrations
arising inside as well as outside the player.
The DP-65 covers all bases, with top quality
in every mechanical as well as electronic
aspect. The end result is a digital signal of
exceptional purity.

The digital and analog sections use an ultra
high speed optocoupler link that guaran»
tees thorough electrical isolation. Two sep»
arate power transformers for the digital and
analog sections provide further separation,
to eliminate any possibility of sound quality
degradation through FlF interference. The
digital volume control and the balanced
output circuitry help to maintain totally
accurate sound reproduction.

Behind the simple and elegant front panel
of this CD player resides a wealth of highly
sophisticated Accuphase technology.
Thanks to the DP-65. the world of digital
audio has just become even more fascinat-
ing and enticing.

MMB type D/A converter yields 20-bit
linearity and minimizes noise
The D/A converter, an essential component
for sound quality, is an MMB type originally
developed for the DC—91. This converter
system has won high praise for its breath-
taking performance and impeccable sound
quality. The acronym MMB stands for “Mul—
tiple Multi-Bit" and refers to a design where
a number of strictly selected 20-bit D/A
converters are connected in parallel, The
parallel drive principle has proven its worth
in many electronic applications, such as
high-performance phono preamplifiers and
high—frequency transistors. When properly
designed, it dramatically reduces noise and
improves frequency response.
The improvement afforded by the parallel
connection is exemplified by the fact that
connecting two elements in parallel will
yield twice the current but distortion and
residual noise will increase only by a factor
of 1.4. The improvement in terms of signal
versus noise in this case is 3 dB. With
several elements in parallel, the improve-
ment can be calculated according to the
following equation, where “n" is the number
of parallel elements:

20 log (1/5) [(18]
Since the DP-65 uses four elements, the
improvement is 6 dB.
Rather than simply linking the converter
elements in parallel, the MMB circuit drives
each converter separately, so that it can
develop its full potential. Special attention
was devoted to phase response at high
frequencies. Parts selection, layout, and
wiring patterns were optimized to achieve
harmonious performance. In other words,
Accuphase applied the parallel connection

principle only after ensuring that each con-
verter would operate perfectly on its own.
This is the real reason why MMB sounds so
good.

Dluital
Input

Operating Principle oi MMB Type ’
D/A Conversion System

As can be seen from the graphI response of
digital input versus analog output is abso-
lutely linear from very high to extremely low
levels, down to an amazing —110 dB (actual
measurement; the limit of 16—bit CDs is 796
dB). Distortion and noise are also virtually
absent, so that the converter attains the
theoretical limits of performance. The sonic
result is breathtaking realism and almost
incredible detail resolution. Even the most
delicate nuances of a pianissimo passage
suddenly emerge with total clarity and fidel—
ity,

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THD(lncluding Noise) vs. Frequency Characterlstlc

High-performance 20-bit, 8-times oversam-
pling digital filter

The purpose of a digital filter is to multiply
the sampling frequency by an integer,
thereby moving any spurious noise compo-
nents far outside the audible range.

The filter in the DP—65 is manufactured by
NPC and employs a linear—phase FIR (Finite
Impulse Response) three-stage design in
the interpolation stage. This assures per-
fect linearity, since the filter introduces no
group delay, and ripple components in the
passband are reduced to an astonishing :
0.00005dB. Attenuation in undesired area is
better than 7110 dB. The filter thus
approaches the theoretical limits of perfor—
mance. The deemphasis stage features an