Accuphase DP 60 Brochure

Page 2

8-time Oversampling Digital Filter, 18-bit D/A Converter Precisely Adjusted
One by One, and Complete Separation Between the Digital
and Analog Sections via the Very High Speed Optoisolators

Utilizing the technology developed tor its pre-
decessor. the top-rated DP-SOL/DC-BtL. Accu»
phases new CD player, the DP760, brings to the
user an attractive world of music, unattainable With
any other CD players of this class,

inside the chassis of the DP-GO. digital Circuitry,
such as the player, is electrically isolated from the
analog circuitry by ultra high-speed. optoisoiators
with a transmission capacity of AOMbits/second. in
addition, special technology protects the internal
circuitry from electromagnetic and static electrrcrty
interierence, thus preventing the sound quality from
being degraded by high-frequency noise.

Carefully selected, top-grade 18bit le are
adopted tor the D/A converters, each oi which is
precisely adiusted on the production line to achieve
upper»lirnit performance. A 20-bit eightvtime over-
sampling filter, the most advanced digital filter, is
provided for both the ielt and the right channels
These digital filters are independent of each other
and achieve an unnecessary band pass attenuation
of -t todB and a bandpass ripple of :ODOOOSdB

The DP-60 can boast a lot more oi Accuphases
state-ol-the-art technology though. such as a horse
shaper that reduces re-quantized noise to near the
theoretical lower limit, a 3-pole GIC iowpass iilter
with excellent amplitude and phase characteristics,
a high-precision digital deemphasis circuit With a
deviation of :0 001dB. and digital remote control
that can adiust the gain up to 724dB in 1dB units

Another ieature oi DP-GO is its rigid construction
and high reststance to vibration and shock, The
linear motor laser pickup is securely mounted on a
diecast aluminum frame and the mechanism itself Is
fixed to a metal chassis of 1.6mm thick, so that the
vibration generated by the motor is almost com-
pletely absorbed. This construction brings the total
weight of DP-SO to 14.5kg. making it one of the
heavrest CD players available

The custom-built 8-bit microprocessor in the DP-
60 gives remarkably short access time oft second
or less.

The side panels of the DP-BO use natural per-
simmon board, following the desogn of the series of
Accuphase models, With only the necessary
switches on the iront panel for ease of operation,

Despite this implicity of appearance, the DPVGO
has many convenient functions, such as power-
ON play" that automatically starts playback when
the power is turned on, and a function to display
and play back in units of one frame (1/75 second),

The DPeGO has opened a new era in the world of
digital audio.

Individually Adjusted 18-bit D/A

Converters
The D/A converter is the heart oi digital audio equip-
ment, The Accuphase DP-GO employs caretulty
selected 18-bit D/A converter iCs ottering excellent
characteristics, These D/A converters are deSigned
speCIticaIiy so that their bit precrsron can be indi-
vrduaily adjusted during the production process to
achieve upper»|imlt periormance

While the number 01 bits 01 3 D/A converter can

be increased by connecting an external Circuit to
the converter The technique has no real eltect on
an lC With a precision as high as 18 bits, In produc-
ing the DP-60, therefore. the utmost emphaSis is
placed on pertecting the 18bit preCision ol the le,
and the long-term stability oi the unit under a variety
oi evrronmental changes All the BIA converters in
the DP-GO have achieved the theoretical upper»limit
characteristics.

independent 20-bit Eight-Time

Oversampling Filters for Both Left and

Right Channels
A digital filter eliminates the causes ot sound quality
degradation by increasing the sampling trequency
in multiples oi tundamental frequency and by em-
ploying the noise-reducrng audio tilter With smooth
cutoff characteristics Therefore. a digital litter that
can only deal in multiples is not enough for practical
applications, and the capability to suppress the
unwanted component in the audio band and be-
tween sampling fre»
quencies is of the ute
most importance.

The DPeGO employs

eight-time oversam-
pling digital filters that
operate on a high-
level digital algorithm
and suppress un-

wanted components in the range of 24%
328,7kH2 to an astonishing level oi at todB Band-
pass ripple, which can cause degradation of sound
quality, is reduced to :0 OOOOSdB, proving that
these digital tilters are the highest in quality current-
ly available on the market.

a-Pole GlC Butterworth Active Filter

Having Specially Selected Elements
Since the sampling frequency is increased eighty
told to 352.8kHz, the signal output from the D/A
converter contains high-frequency components of
over 332,8kHz (=852,8-20), Oi course, unwanted
components also exist in sampling frequencies that
are increased 16-fold, 24-fold. and so on. An audio
lowpass lilter that cuts oft these unwanted high~
frequency components should only have moder-
ate. S-pole (thB/ocl.) characteristics. The dis-
crete 3»poie GlC Butterworth active filters employ<
ed in DP-60 are made up ol specially selected
elements to improve the sound quality

Digital Circuitry and Analog Circuitry are
Completely Isolated to Prevent
Degradation of Sound Quality by J
High-Frequency Noise
Digital signals have components of very high fre-
quency, which may mutually interiere with demod-
ulated audio signals, degrading the sound quality,
To prevent this, it is essential to completely isolate
the digital circuitry irom the analog circuitry to sup
press the influence of static electriCity and elec-
tromagnetism.

The digital circuitry, including the player, of the
DPeSO is electrically isolated by optoisolators from
the analog circuitry in the stage following the D/A
converter, Four ultra high-speed. optoisolators with
a transmission capacity of AOMbits/second are pro»
vided lor each channel, so that only high-fidelity
signals are transmitted in the torrn of light.

But though the digital and analog circuitry are

From
digital tiller

Digital/analog separation circuit
via optolsolators