● DP-900: Digital-only SA-CD/CD transport ● High-rigidity, high-precision
SA-CD/CD drive ● Accuphase original digital interface: HS-LINK ● DC-901: Digitalprocessor with revolutionary SA-CD reproduction technology MDSD ● MDS type
D/A converter with 16 circuits driven in parallel ● “Direct Balanced Filter” with totally
separate line and balanced signal paths ● Seven inputs including HS-LINK and USB

PRECISION SA-CD TRANSPORT

Dedicated digital-output SA-CD/CD transport

Totally new ultra-massive

SA-CD/CD drive. Highly rigid, high-precision construction with low center ofgravity absorbs vibrations. Finely machined and utterly smooth disc loadingmechanism with exquisite tray. High-performance digital audio interface HS-LINK.

HS-LINK cable

The center of the DP-900 features a high-rigidity, high-precision
SA-CD/CD drive integrated directly with the ultra-massive bridge.
Two super-efficient toroidal transformers and an array of filtering
capacitors provide ample power. As an SA-CD/CD transport of thehighest order, the DP-900 delivers a digital signal of the utmost purity.

DP-900: SA-CD output

Digital
Audio
SignalHS-LINK
Encoder

TIA/EIA-644 LVDS
Driver/Receiver

RJ-45
Connector
Security
ControlPRECISION MDSD DIGITAL PROCESSOR

Digital processor designed for purest digital signal quality
Digital signal
processing using ultra-high-speed FPGA. Further evolved original MDSD(Multiple Double Speed DSD) reproduction technology with double-speed
high-precision moving-average filter circuit for straight D/A conversion of DSD
signal. Seven digital inputs including HS-LINK and USB for enhanced versatility.

TIA/EIA-644 LVDS
Driver/Receiver

HS-LINK
Decoder

RJ-45
Connector
Security
Control

Digital
Audio
Signal

DC-901: SA-CD input

The DC-901 is the ultimate digital processor using only speciallyselected materials and super-advanced digital technology. Glassfluorocarbon resin PCBs in DAC section, and completely separate
power transformers for digital and analog circuitry assure music
reproduction that brings out the full sonic potential of the source.

DP-900 Features and Functions
PRECISION SA-CD TRANSPORTThe SA-CD Transport DP-900 and the Digital Processor
DC-901 are successor models to the highly regarded
DP-800 and DC-801 combo. Incorporating the pinnacleof SA-CD playback technology know-how and inspiredby a passion for true high-end audio sound, this new
separate-type SA-CD/CD system harnesses latest digitaltechnology for the ultimate in reproduction fidelity.
The SA-CD drive in the DP-900 was developed in-houseby Accuphase to assure the best possible performance.
Its ultra-massive design combines superior rigidity withoutstanding accuracy. Compared to a CD drive, an
SA-CD drive has a higher revolution rate, and pickup
positioning accuracy as well as suppression of vibrations
must be of a higher order, to allow full access to theenormous amount of information stored on the disc. The
transport in the DP-900 meets these challenges in
impressive fashion, being designed to extract the quality
potential of the SA-CD one-hundred percent. It ushers in
a new generation of SA-CD excellence.
In the transport, a digital servo with a dedicated DSP
assures accurate readout of the signal recorded on the
SA-CD using the DSD (Direct Stream Digital) principle.
This is sustained by a single-lens/twin laser diode pickup
mounted to a high-speed access mechanism. The
mechanism not only realizes optimal reproduction of
SA-CDs, it also is capable of extracting a super-accurate
signal from conventional CDs. The output for both
SA-CD and CD is provided via the Accuphase exclusive
high-performance digital interface HS-LINK (RJ-45
connector). The CD output is also available via a
dedicated coaxial connector. The HS-LINK cablesupplied with the DP-900 can be used for connection to the DC-901 or to other components.
■Remote commander RC-110 supplied with DP-900
Controls DP-900 functions such as
direct play, repeat, etc. Also controls
DC-901 functions such as input
switching and output level adjustment,
and can serve for volume control of
Accuphase amplifiers.

■ Dedicated digital output only SA-CD/CDtransport with ultra-high-speed FPGA for
digital processing and highly accurate signal
pickup.
■ Ultra massive chassis construction andnewly developed high-rigidity, high-precision
SA-CD/CD drive.
■ Sophisticated signal processing technology
assures excellent signal quality also fromconventional CD media.

System controller assembly■ Single-lens/twin pickup high-speed accessmechanism employs two laser diodes, one
for SA-CD (650 nm) and one for CD (780 nm).
■ Accuphase’s proprietary high-quality digitalaudio interface HS-LINK.

High-speed FPGA for
digital signal processing■ RJ-45 output (HS-LINK) for SA-CD and CD,
and dedicated coaxial output for CD. HSLINK connection to DC-901 can carry both
SA-CD and CD signals.
■ Power supply with two high-efficiency toroidal transformers and custom-made highquality filtering capacitors (3000μF × 10)
allows separate powering of signal processing circuitry and drive section.

System controller chip

HS-LINK output connector
Coaxial output connector■ Display can show text data with disc title,
artist information, etc.
■ “High Carbon” cast iron insulator feet withsuperior damping characteristics ensure
quiet operation of both DP-900 and DC-901,
and further enhance sound quality.
■ Both DP-900 and
DC-901 feature massive cabinets withwood finish.

High-efficiency toroidal transformers

High-quality parts selected forsound quality
Power supply assemblyNewly developed high-rigidity, high-precision SA-CD/CD drive■ External vibrations are reliably blocked by super-massive sturdy
chassis (total weight 10.7 kg)■ Highly rigid and precise construction■ “Traverse Mechanism” with floating design and viscous damping■ Integrated construction with large heavyweight aluminum alloy bridge
mounted to mechanism base■ High-quality disc tray extruded from an aluminum block■ Super-quiet smooth disc loading mechanism featuring dual stay
configuration for steel bearing shafts■ Low center of gravity further reduces vibrations

8 mm thick aluminium frame

Aluminum alloy bridge

Traverse mechanism

Disc tray

In order to extract the minute bits of information from the rapidly
spinning disc and decode these accurately into a digital signal ofhigh purity, vibrations emanating from the rotating medium aswell as any external mechanical vibrations must be minimized.
Compared to a CD drive, the disc in an SA-CD drive spins at
higher rate. In order to extract the high-density information fromthe media, the mechanism must be built to a high degree of
accuracy, to ensure precise pickup positioning and effective
suppression of vibrations.
In the DP-900, the SA-CD/CD drive is mounted firmly to a strong
aluminum frame, and the drive loading mechanism andmechanical base form a massive and highly rigid chassis
constructed with utmost precision. Conversely, the traverse
mechanism, an integrated structure consisting of the opticalassembly including laser pickup and rotating parts, is designed
for extremely light weight, and isolated from the loadingmechanism by a floating suspension arrangement. A large,
super-heavy bridge machined from a single block of aluminum isjoined to the mechanism base to form an integrated structure.
The entire SA-CD/CD drive assembly is directly mounted to thebottom chassis, and four large cast iron insulator feet provide
firm support.
Vibration transmission characteristics of pickup base
When there are resonant peaks in the frequency range below 100 Hz,
the pickup may be subject to dropouts that will cause sound degradation.
The Accuphase design effectively minimizes resonances in this range.
Acceleration (m/s2)

Conventional product

0.3
0.2

Mechanism base

0.1
0

0

20

40

60

80

60

80

Acceleration (m/s2)

Dual stay bearing shafts

0.3
0.2

100

Frequency (Hz)

Accuphase in-house developed drive

0.1

12 mm thick heavyweightbottom plate

0
0

20

40

100

Frequency (Hz)Viscous dampers

Connection example: DC-901 p
Accuphase Exclusive Digital Interface: HS-LINK
HS-LINK (High Speed Link) is an ultra high-quality digital audio interface developed by
Accuphase using latest digital signal transmission technology. It allows a single dedicated
HS-LINK cable to transmit all audio data with utmost fidelity.
Sampling frequencies

The DC-901 is equipped with a total of seven input
here, this allows its use for reproducing music informa computer or other equipment at high quality. In add
allow sound field compensation in the digital domain
DP-900■ Capability to carry the SA-CD signal as well
32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz,as conventional digital audio signals
176.4 kHz, 192 kHz (24 bit, 2-channel PCM)
2.8224 MHz (1 bit 2-channel DSD)
■ Transfer rate: min. 400 Mbps
HS-LINK(logical limit 1923 Mbps)
A single HS-LINK cable
HS-LINK cable
carries both SA-CD and■ Transfer signal format: Low Voltage Differential
CD signals.
Signaling (LVDS) TIA/EIA-644
DC-901■ Send/receive clock fully synchronized■ Full bidirectional capability with simultaneous send/
receiveSeven digital inputs
AHDL-15■ Full security capability with send/receive verification.
Newly developed HS-LINK cable (supplied with DP-900)■ Cable type: dedicated HS-LINK cable● Cable length: 1.5 m● Triple shielded twisted pair 8-conductor OFC cable

SA-CD
OpticalHead

DigitalSignal
Processor

Digital Audio
Interface
Encoder

LVDS
Driver/Receiver

EXTERNAL DSP
inputs/outputs
HS-LINK
COAXIAL

RF
Signal
Processor

Clock
Generator

SA-CD,CD

Motor&
Actuator■ DP-900 Block Diagram

From
RemoteCommander

Infrared
Receiver

DG-48

Advanced High Carbon cast ironinsulators for best sound
MasterControlComputerKey
Matrix

Display

Optical fiber cable

OUTPUTS

butto
DIGITAL OUT

DigitalServo
Processor

Coaxial cable

HS-LINK cable

Driver
COAXIALOUTPUT

DIGITAL OUT

An
INPUTS

HS-LINKOUTPUT
CD
OpticalHead

T-1100

DIGITAL IN

set to ON

Connecting the
DG-48 via HS-LI
sound field com
digital domain forDC-901 Features and Functions
PRECISION MDSD DIGITAL PROCESSORThe DC-901 showcases Accuphase’s mastery ofsophisticated digital technology and creative circuit
topology. It is a digital processor designed to bring out
everything the SA-CD format has to offer. A newtechnique called MDSD (Multiple Double Speed DSD)
allows straight D/A conversion of the DSD signal.
Multiple DSD signals delayed through digital processing
in an ultra-high-speed FPGA (Field Programmable Gate
Array) are converted by separate D/A converters. After
D/A conversion, summation of the multiple data is
performed, resulting in an ingenious moving-averagefilter circuit with double-speed accuracy. An importantcharacteristic of MDSD is the use of MDS type D/Aconverters which keeps conversion errors to an absolute
minimum. At the same time, the MDSD circuit acts as ahigh-cut filter with completely linear phasecharacteristics. The end result is a digital signal ofoutstanding quality, allowing the music to emerge inperfect clarity, demonstrating the ultimate potential of
the SA-CD format.
The DC-901 offers an array of seven digital inputs,
namely HS-LINK, balanced, coaxial (2), optical (2), andUSB. This enables use of the processor for reproducing
music information from various sources, including the
DP-900, a computer or other equipment at high quality.
Digital outputs are also provided, allowing connection ofa digital recorder, for recording of sources other than
SA-CD. And there’s even a set of EXTERNAL DSP
input/output connectors that allows using the Digital
Voicing Equalizer DG-48 for sound field processing in
the digital domain. Dedicated power transformers for thedigital and analog sections and completely separate
construction prevent high-frequency noise andunwanted electrical interaction, ensuring that musicsignal retains its absolute purity.

■ Ultra-high-speed FPGA (Field Programmable Gate
Array) harnesses digital processing power to implement
innovative MDSD reproduction with double-speed
high-precision moving-average filter circuit.
■ Sixteen MDS type D/A converters driven in parallel.
Each channel uses two Hyperstream™ DAC chips(ES9018 made by ESS Technology) in parallel. Eachchip incorporates eight converters, resulting in 16
circuits. This improves performance by a factor of about
4 (= 16) compared to a single converter, providing theoutstanding low-distortion results seen in the graph.
■ “Direct Balanced Filter” performs totally separate
analog low-pass filtering for line and balanced signal
paths.

Left/right PCB assembly with MDSD and analog output circuitry■ D/A converter printed circuit boards made from glass
fluorocarbon resin with low dielectric constant and low
loss.
■ EXTERNAL DSP input/output connectors (HS-LINK and
optical) allow insertion of DG-48 in signal path.
■ Seven digital inputs: HS-LINK, balanced, coaxial (2),optical (2), USB.

Ultra-high-speed FPGA
Analog output〔dB〕

LINEARITY

0
−10
−20

■ Coaxial and optical
digital outputs.

−30■ Line and balanced
analogoutputs(1 each). Phase selector switch for balanced output.

−70■ Completely separate construction ofdigital and analog
sections, each powered by a dedicatedhigh-efficiency toroidal transformer.

32-bit DAC (ES9018)

−40
−50
−60
−80
−90
−100
−110
−120
−130
−140
−140

Digital signal processing assembly

−120

−100

−80

−60

−40

−20

0 〔d
Digital inp

Linearity (digital input vs. analog output)〔%〕 0.01
0.007
0.005
0.003
0.002

0.001
0.00070.0005provides seven digital inputs

0.00030.0002

Power supply assembly

uts for digital signals from other devices. As shownrmation from various sources, including the DP-900,
ddition, a set of EXTERNAL DSP inputs and outputs
n, using the DG-48.

CD transport or otherdigital source equipment
DIGITAL OUT

USB cable

USB

Computer

Audio
cable

Preamplifier

nalog output

ton on DC-901

e DC-901 and
INK cable allows
mpensation in theor all inputs.

Digital input assembly with 7 inputs: HS-LINK,
balanced, coaxial (2), optical (2), USB

0.000120 30

50 70 100

200

500

1k

2k 3k

5k

10k

20k 〔

THD (including noise) vs. frequency respon

Innovative Digital Processing: MDSD (Multiple Double Speed DSD)The DSD signal by principle contains increased quantization noise components outside the range of human hearing, which must be removed. For this purpose,
the DC-901 employs an ultra-high-speed FPGA to implement innovative MDSD reproduction through digital processing, forming a double-speed high-precision
moving-average filter circuit. The major distinction of this MDSD design is the fact that it combines signal summation after conversion by multiple D/Aconverters (to minimize any conversion errors) with an outstanding 15-pole high-cut filter function providing perfectly linear phase characteristics.
MDS D/A Conversion System
Digital signal input

Normal phase output

DSD signal

Delay(2.8224 MHz/1 bit)

1/ 2 Delayed by 1/2 clock cycle

Delay

0 〔dB〕

al input

ut)

DAC 2

Delay
1 Delayed by 1 clock cycle

The moving-average filter circuit
as implemented by the MDSD
method in the DC-901 employs atotal of 15 delay devices and 16
D/A converter circuits.
The DSD input signal (2.8224
MHz/1 bit) is slightly shifted byeach delay circuit. The resulting
delayed signals are divided into
two groups which are supplied to
the 16 D/A converters for digitalto analog conversion.
The two D/A converter blocks
operate alternately, producing theaction of a double-speed high-cut
filter. The converted signals arethen summed.

try

Reverse phase
output1 Delayed by 1 clock cycle

Double speed high-precision
moving-average filter circuit

DAC 1

Discrete I-V
converter

DAC 3Group 1

Delay

DAC 8

＋

7.5 Delayed by 7.5 clock cycles《Reference waveform》

DAC output
−

DAC 9

Delay
1 Delayed by 1 clock cycle

DAC 10Delay
1 Delayed by 1 clock cycle●High-cut filter function reliably
removes signal components outside
the range of human hearing (almost
exclusively noise components).
●Conversion errors that could affectsignal components in the range ofhuman hearing are canceled out.

Discrete I-V
converter

DAC 11
Group 2
Normal phase
outputDelay

DAC 16
7 Delayed by 7 clock cycles

Reverse phase
output《15 delay circuits shift input signal in very small increments》

Discrete I-V converter《16 DAC signals are summed》

Using USB cable to connect a computer

Direct Balanced Filter circuit

The DC-901 is equipped with a USB port (Type B). This allows a computer with a music library
to be connected via a USB cable (with Type B plug), for playback of high-resolution music data
(up to sampling frequency 192 kHz/24 bit) with high quality.

0k 〔Hz〕＊ Before using the USB port, install thesuitable software for the computer from the
supplied USB Utility CD-ROM.

ponse

USB port

USB cable(with Type B plug)
USB port

PC＊ Playback of music data via the USB link isdependent on the operating system andmusic playback software of the computer.

1

2

OpticalRX

1

CoaxialRX

2

CoaxialRX

MDSD (Multiple Double Speed DSD) System

BalancedRX

HS-LINK

HS-LINK
RX

COAXIAL

CoaxialTX

OPTICAL

OpticalTX

HS-LINK

HS-LINK
TX

DigitalOutputs

OUTPUTS
External
DSP■DC-901 Block Diagram

COAXIAL

CoaxialTX

HS-LINK

HS-LINKRXINPUTS
COAXIAL

CoaxialRX＋ 5-Pole

MDS
D/A Conversion−

Butterworth
Low-Pass Filter
LINE

× 16

Delay

ΔΣ DACDSD
signalCOAXIAL

BALANCED

connected preamplifier or
integrated amplifier has a“pin w +” arrangement,
the switch should be set to
the right side.

Preamplifier

OPTICAL

DigitalInputsis set to the left side (“pin e +”).

Audio
cable

Delay
OpticalRX● In the factory default condition, the switch● If the balanced input of the

DC-901

USB
RX

USB

Phase selector switch forbalanced output＊ For information on USB settings andconnection, refer to the documentation of
the computer.

AnalogoutputUSB port (Type B)

High-precision OP
amp OPA1612

The analog filter section designed to remove aliasing noise fromthe output of the D/Aconverter employs completely separate 5-pole
Butterworth low-passfilters for the line output
and balanced output.

＋

−

PCM
signal

＋ 5-Pole−

Butterworth
Low-Pass Filter＋

BALANCED＋ 5-Pole−

Butterworth
Low-Pass Filter

Balanced
Conection

Left
AnalogOutputs−

Interface
Decoder

MDSD (Multiple Double Speed DSD) System
Delay＋ 5-Pole

MDS
D/A Conversion−

Butterworth
Low-Pass Filter
LINE

× 16

Delay

DSD
signalPCM
signalΔΣ DAC＋−＋ 5-Pole−

Butterworth
Low-Pass Filter＋

BALANCED＋ 5-Pole−

Butterworth
Low-Pass Filter

Balanced
Conection

Right
AnalogOutputs−

DP-900■ Front panel

y

q

w e r

u

i

DC-901■ Front panelto!0 !1 !2 !3■ Rear panel

q

r

w

t

e

u

y

■ Rear panel

!4

★

!5
q SA-CD/CD indicator
Lit: SA-CD
Out: CDw Track display
e Index display
r Time display
t Repeat indicator
ALL/ONEy Power switchu SA-CD/CD button
i Disc tray

!1

i

o
Disc tray open/close button!0Play button!1
Pause button!2 Track search buttons
BACK,
NEXT
!3
Stop button!4 Digital output connectors
HS-LINK (SA-CD/CD signal)
COAXIAL (CD signal only)!5 AC power connector★

o

!2

!3

!4★

!0

q Alphanumeric input display
w Function indicators
EXT DSP, LOCKED, MDSDe Output level display
r Power switch
t EXT DSP button ON/OFFy Input selector buttons
USB, OPTICAL 1, 2, COAXIAL 1, 2
BALANCED, HS-LINK
u Output level control buttons
DOWN, UPi Digital input connectors
HS-LINK, BALANCEDCOAXIAL 1, 2, OPTICAL 1, 2

o EXTERNAL DSP connectors
INPUTS (HS-LINK, COAXIAL)OUTPUTS (HS-LINK, COAXIAL)!0 DIGITAL output connectors
COAXIAL, OPTICAL!1 Analog line output connectors!2 Analog balanced output connectors
Pin ② − Pin ③ +(Can be switched with phaseselector switch !3)!3 Phase selector switch!4 AC power connector★

Remarks★ This product is available in versions for 120/220/230 V AC. Make sure that the voltage shown on the rear panel matches the AC line voltage in your area.
★ The shape of the AC inlet and plug of the supplied power cord depends on the voltage rating and destination country.

DP-900 Guaranteed Specifications● Compatible
2-channel SA-CD (Super Audio CD)
disc formats CD● Data read principle Non-contact optical pickup● Laser diode wavelength
SA-CD: 650 nm
CD:
780 nm● Digital outputs
HS-LINK
Connector type: RJ-45
Suitable cable: dedicated HS-LINK cable
SA-CD:
2.8224MHz / 1bit DSD
CD:
44.1kHz / 16bit PCM
COAXIAL
Format:IEC 60958 compliantCD:
44.1kHz / 16bit PCM● Power requirements
120 V, 220 V, 230 V AC (voltage as indicated on rear panel)
50/60 Hz● Power consumption 11 W
● Maximum dimensions
477 mm (W)×156 mm (H)×394 mm (D)● Weight
30.0 kg (66.14 lbs) net
36.0 kg (79.37 lbs) in shipping carton●

DC-901 Guaranteed Specifications [Guaranteed specifications are measured according to JEITA standard CP-2402A]● Digital inputs
HS-LINK
Connector type: RJ-45
BALANCED Format:
IEC 60958/AES3 compliant
Suitable cable: 110 ohm digital balanced cable
COAXIAL
Format:IEC 60958/AES3 compliant
Suitable cable: 75 ohm digital balanced cable
OPTICAL
Format:JEITA CP-1212 compliant
Suitable cable: JEITA standard optical fiber cable
USB
Format:USB 2.0 High Speed(480 Mbps compliant)Suitable cable: USB cable with Type B connector● Supported sampling frequencies
HS-LINK
32 kHz to 192 kHz / 24 bit (2-channel PCM)
2.8224 MHz / 1bit (2ch DSD)
USB, COAXIAL, BALANCED
32 kHz to 192 kHz / 24 bit (2-channel PCM)
OPTICAL
32 kHz to 96 kHz / 24 bit (2-channel PCM)
● Digital outputs
COAXIAL
Format: IEC 60958 compliant
OPTICAL
Format: JEITA CP-1212 compliant

Supplied with DP-900

Supplied with DC-901● AC power cord

● AC power cord

● HS-LINK cable● Audio cable with plugs (1 m)(AHDL-15 equivalent)● Remote Commander RC-110● Cleaning cloth● USB Utility Setup Guide● USB Utility CD● Cleaning cloth● D/A converter

MDSD principle (DSD signal)
MDS principle (PCM signal)● Frequency response
0.5 to 50,000 Hz +0, −3 dB● Total harmonic distortion 0.0005% (20 to 20,000 Hz)● Signal-to-noise ratio
120 dB● Dynamic range
117 dB● Channel separation
120 dB (20 to 20,000 Hz)● Output voltage and impedance
BALANCED: 2.5 V 50 ohms, balanced XLR typeLINE:
2.5 V 50 ohms, RCA phono jack● Output level control
0 dB to −80 dB (digital)● Power requirements
120 V, 220 V, 230 V AC
(voltage as indicated on rear panel)
50/60 Hz● Power consumption
26 W● Maximum dimensions
477 mm (W)×156 mm (H)×394 mm (D)● Weight
23.4 kg (51.59 lbs) net
30.0 kg (66.14 lbs) in shipping carton

Optional HS-LINK cable● AHDL-15 (1.5 m)＊ AHDL-30 (3.0 m) available by special orderSpecifications and design subject to change without notice for improvements.
G1105Y PRINTED IN JAPAN

851-0207-00（B1）