Accuphase DP 11 Brochure

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Utilizing the technology developed for its pre-
decessor. the top-rated CD player. Accuphase's
new CD player. the DP-l1. brings an attractive
world of music tothe user, unattainable by any other
CD player of this class.

Inside the chassis of the DP-i 1, digital circuitry,
such as the player. is electrically isolated from the
analog Circuitry by ultra high-speed. 40M bits/sec-
ond optoisolators. in addition. special technology
protects the internal circuitry from electromagnetic
and static electricity interference. thus preventing
the sound quality from being degraded by high-
frequency noise.

Individually Adjusted 18-bit D/A

Converters
The D/A converter is the heart of digital audio
equipment. The Accuphase DP-lt employs care-
lulIy selected 18~bit D/A converter le offering ex-
cellent characteristics, These D/A converters are
designed specifically so that their bit precision can
be individually adyusted during the production pro-
cess to achieve upper-limit performance.

While the number of bits of a D/A converter can
be increased by connecting an external circuit to
the converter. This technique has no real eflect on
an IC with a precision as high as 18 bits. In produc-
ing the DP-it. therefore. the utmost emphasis is
placed on perfecting the 18-bit precision of the ICs.
and the long-term stability ofthe unit under a variety
of evironmental changes. All the BIA converters in
the DP-i1 have achieved the theoretical upper-limit
characteristics.

Independent 20-bit Eight-Time

Oversampling Filters for Both Left and

Flight Channels
A digital filtereiiminates the causes of sound quality
degradation by increasing the sampling frequency
in multiples of fundamental frequency and by em-
ploying the noise-re-
ducing audio filter
with smooth cutoff
characteristics,
Therefore. a digital
filter that can only
deal in multiples is not
enough for practical
applications, and the

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

Carefully selected, top-grade 18-bit ICs are
adopted for the BIA conveners. each of which is
precisely adjusted on the production line to achieve
upper-limit performance. A 20-bit eight-lime over»
sampling filter. the most advanced digital filter. Is
provided for both the left and the right channels
These digital filters are independent of each other
and achieve a remarkable bandpass attenuation of
~110dB and a bandpass ripple of i0.00005dB.

The DP-11 can boast a lot more of Accuphase's
state-of-thean technology though. such as a noise
shaper that reduces quantized noise to near the
theoretical lower limit. a 3-pole GIC Iowpass filter

capability to suppress the unwanted components
in the audio band and between sampling lrequen-
cies is of the utmost importance.

The DP-tt employs eight-time oversampling di-
gital lilters that operate on a high-level digital al-
gorithm and suppress unwanted components in the
range of 24.1 to 328.7kt-lz to an astonishing level cl
-110dB. Bandpass ripple. which can cause de-
gradation ot sound quality. is reduced to
10.00005dB, proving that these digital filters are
the highest in quality currently available on the
market.

3-Pole GIC Butterworth Active Filter

Having Specially Selected Elements
Since the sampling lrequency is increased eight-
fold to 352.8kHz. the signal output from the D/A
converter contains high-lrequency components of
over 332.8kHz (=352.8-20). Of course. unwanted
components also exist in sampling frequencies that
are increased 16-fold. 24-fold. and so on. An audio
Iowpass filter that cuts off these unwanted high-
lrequency components should only have moder-
ate. 3«pole (tadB/oct.) characteristics. The dis-
crete 3-pole GIC Butterworth active filters employ-
ed in DP-tt are made up of specially selected
elements to improve the sound quality.

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

The digital circuitry. including the player. of the
DP-lt is electrically isolated by optoisolators from
the analog circuitry in the stage following the D/A
converter. Four ultra high-speed. 40M-bit/second
optoisolators are provided for each channel. so that
only high-fidelity signals are transmitted in the form
of light.

But though the digital and analog circuitry are
isolated. high-frequency noise may be transmitted
along the power cable. Therefore, the digital and

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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 down to -24dB in tdB
steps.

Another feature of DP-tl is its rigid construction
and high resistance to vibration and shock, Tt
linear motor laser pickup is securely mounted o
diecast aluminum frame. This construction brings
the total weight of DP-tt to almost 14kg. making it
one of the heaviest CD players available.

The DP-tl has opened a new era in the world of
digital audio

analog circuits have their own independent power
transformers to maintain their isolation. In addition.
the power to the left and right channels is supplied
from different windings to improve audio charac-
teristics H

High-frequency noise may also travel through at
causing static electricity and electromagnetic inter-
ference. Electrically isolating the digital and analog
circuits is therefore not enough to protect them from
the adverse influence of high~frequency noise. For
this reason. both the analog and digital circuits of
the DP-11 are completely shielded with a thick
metal plate.

Selection Time of 1 Second or Less is

Achieved by Employing a Linear Motor

Laser Pickup and 8-bit Microprocessor
Direct key selection is an attractive feature of CD
players. The DP»11 employs the most advanced
linear motor mechanism for swift and smooth track-
ing of the laser pickup. With this mechanism and the
8-bit microprocessor developed for this CD player,
selection time of l second or less is achieved,
Additionally. the disc table is controlled by micro-
processor. guaranteeing smooth operation.