Accuphase DC-37 User Manual

● MDSD type D/A converter using eight parallel circuits ● Direct Balanced

Filter with totally separate line and balanced signal paths ● Support for

5.6448 MHz 1-bit 2-channel DSD and 384 kHz 32-bit 2-channel PCM ● Six
digital interface inputs including HS-LINK and USB ● Phase selector for
balanced outputs ● Sampling frequency and quantization bit display for input
signal ● Separate power tra nsformer s for digital and analog sections

State-of-the-Art Digital Processor — Innovative MDSD (Multiple Double Speed DSD)
digital processing circuitry with double-speed high-precision moving-average filter
circuit configuration for straight D/A conversion of DSD signal. Support for playback
of high-resolution sources in 5.6448 MHz (1-bit 2-channel DSD) and 384 kHz (32-bit
2-channel PCM) format. Six digital inputs including HS-LINK and USB. Informative
readout shows sampling frequency and number of quantization bits of input source,
based on actual measurement.

In 2011, Accuphase introduced the ultra high-end
separate type Precision SA-CD/CD Transport DP-900
and Precision MDSD Digital Processor DC-901 combo,
which was positioned as the second entry in the

any's 40th anniversary commemorative model

comp
lineup. In 2013 Accuphase followed these with the
integrated type SA-CD/CD player DP-720 featuring a
further evolved MDSD D/A converter with support for a
variety of sources. Both the technical excellence and
stunning sound quality of these products were highly
lauded, earning them a secure place as reference
components in Japan as well as abroad.
The DC-37 inherits the outstanding technology of the
DC-901 and DP-720, while opening a new chapter in
ultra-advanced and innovative digital signal processing

technology. It features an MDSD type D/A conve
that achieves straight conversion of the DSD signal and
supports 5.6448 MHz (1-bit 2-channel DSD) sources.
In keeping with this development, the HS-LINK
interface has also been upgraded to Version 2
significantly expanded sampling frequency and
quantization support up to 5.6448 MHz (1-bit 2-channel
DSD) and 384 kHz (32-bit 2-channel PCM).
The DC-37 also offers convenience and flexible
fun

ctionality. External digital sources can be connected
via a total of six digital inputs: HS-LINK, COAXIAL 1,
COAXIAL 2, OPTICAL 1, OPTICAL 2, and USB.
Accepting digital data for example from a computer o
other components, this new standalone processor turns
the information into musical signals of unprecedented

■ Ample clean power is provided by separate power supplies

for the digital and analog sections, each with a dedicated
power transformer and large filtering capacitors.

■ 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.

■ MDS++ type D/A converter with eight circuits driven in

parallel.

One 32-bit Hyperstream™ DAC chip (ES9018 from ESS

Technology Inc.) is used per channel, each comprising eight
circuits driven in parallel. This improves overall performance
by a factor of about 3 as compared to a single converter circuit,
thereby achieving outstanding low-distortion results.

■ Direct Balanced Filter uses high-precision op-amps and

performs totally separate analog filtering for line and
balanced signal paths, to prevent any risk of interference
when both are used simultaneously.

■ Six digital inputs: HS-LINK, coaxial (2), optical (2), USB.

■ Line and balanced analog outputs (1 each). Phase selector

switch for balanced output.

Features and Functions

Assembly with MDSD and analog output circuitry

USB chipHigh-precision op-amp

Digital signal processing assembly

quality. A front panel display shows not only the sampling

rter

frequency of the selected so

urce, but also the number of
quantization bits, based on actual measurement of the
signal. Two completely separate power supplies, each

with

with a dedicated power transformer, are used for the
digital and an

alog sections, to prevent any possibility of
RF noise or electrical interference that could degrade the
sonic purity of the output.
The DC-37 is a digital processor that redefines the
state-of-the

art and has its sights firmly set on the future,
including computer-based and high-resolution audio. Only
strictly selected circuit components, materials and other

r

parts of the highest quality are used,
immense richness of information that translates into a
spectacular musical experience.

Power transfo rmer

Input selector

Assembly with 6 digital inputs

Phase selecto r

Power supply assembly

Parts selected for high sound quality and reliability

resulting in an

Digital
Inputs

Remote Commander

HS-LINK

Coaxial 1

Coaxial 2

Optical 1

Optical 2

USB

Infrared

Receiver

From

HS-LINK
Receiver

Coaxial

Receiver

Coaxial

Receiver

Optical

Receiver

Optical

Receiver

USB

Receiver

Master

Control

Computer

Key

Matrix

Interface
Decoder

Display

Block Diagram

MDSD（Multiple Double Speed DSD）System

Delay

Delay

DSD Signal

PCM Signal

MDSD（Multiple Double Speed DSD）System

Delay

Delay

DSD Signal

PCM Signal

D/A Conversion

DAC

×

D/A Conversion

DAC

×

MDS

8

MDS

8

＋＋

＋＋

5-Pole

Butterworth

Low Pass Filter

5-Pole

Butterworth

Low-Pass Filter

5-Pole

Butterworth

Low Pass Filter

5-Pole

Butterworth

Low Pass Filter

5-Pole

Butterworth

Low Pass Filter

5-Pole

Butterworth

Low Pass Filter

Line

Balanced

Line

Balanced

Left
Analog
Outputs

Right
Analog
Outputs

Innovative Digital Processing: MDSD (Multiple Double Speed DSD) Playback Principle

Digital input

DSD signal

5.6448 MHz 1-bit

32-bit Hyperstream™ DAC chips

2-channel DSD

In the DC-37, the eight circuits of the 32-bit Hyperstream™
DAC chip (ES9018 from ESS Technology Inc.) are driven
in parallel (using clock shift for DSD), thereby improving
overall performance by a factor of about 3, as compared
to a single converter circuit.
Because the performance improvement afforded by the
MDS++ principle is independent of signal frequency and
signal level, output signal noise at very low levels is
also successfully minimized, a feat that is very difficult
to achieve with conventional delta-sigma converters.
By locating a dedicated quartz oscillator very close to
the ES9018 chip and using it as a master clock to drive
the D/A converter in asynchronous mode, jitter is also
significantly reduced.

Sampling frequency and number of

quantization bits shown on display

The readout shows the sampling frequency of
the source chosen by the input selector, as well
as the number of quantization bits input to the
DAC, as determined by actual measurement.



FREQUENCY

Indicat es l oc ke d- in sampling
frequen cy ( kH z) o f signal.



BIT

Indicates actual number of
bits (in 1-bit steps) as
input to DAC.

Display example

〔%〕

0.0100

0.0050

0.0030

0.0020

0.0010

0.0005

0.0003

0.0002

0.0001
30 50 100 200 500 1k 2k 3k 5k 10k

20

Total harmonic distortion (incl. noise) vs. frequency response

Eight D/A converter circuits driven in
parallel ensure outstanding performance
in all aspect, including superb S/N ratio
and amazingly low harmonic distortion.

Delay

device

(Reference waveform)

Delay

device

Delay

device

Delay

device

THD+NOISEvs.FREQUENCY

Dou ble Sp eed Moving Ave rag e F ilt er Circuit

(Input signal slightly shifted by 7 delay devices)

1/2

Delay

device

Delay

device

Delay

device

Delayed by     clock cycle

1

Delayed by   clock cycle

Delayed by   clock cycle

Delayed by    clock cycles

3.5

1

Delayed by   clock cycle

Delayed by   clock cycle

Delayed by   clock cycles

3

1

HS-LINK Ver. 2 is an upgraded version of the Accuphase HS-LINK interface,
providing significantly expanded sampling frequency and quantization support
up to 5.6448 MHz (1-bit 2-channel DSD) and 384 kHz (32-bit 2-channel PCM).

●

The DC-37 supports HS-LINK Ver. 2 and is therefore compatible with both
HS-LINK and HS-LINK Ver. 2 signals.

20k

〔Hz〕

HS-LINK HS-LINK Ver.2

32.0 kHz, 44.1 kHz, 48.0 kHz,

88.2 kHz, 96.0 kHz, 176.4 kHz,

192.0 kHz /
16 to 24-bit 2-channel PCM

2.8224 MHz /
1-bit 2-channel DSD



＋＋

MDS

Group 1

1

Group 2

D/A Conversion System

Normal phase output

DAC 1

Reverse phase

output

DAC 2

DAC 3

DAC 4

DAC 5

DAC 6

DAC 7

Normal

phase output

DAC 8

Reverse phase

output

I-V

converter

I-V

converter

Current summing /

I

-V conversion

(Overall summing of 8 DAC signals)

＋

DAC output

−

HS-LINK Ver. 2

Sampling frequency/Quantization bits

32.0 kHz, 44.1 kHz, 48.0 kHz,

88.2 kHz, 96.0 kHz, 176.4 kHz,

192.0 kHz, 352.8 kHz, 384.0 kHz /
16 to 32-bit 2-channel PCM

2.8224 MHz, 5.6448 MHz /
1-bit 2-channel DSD

＊ HS-LINK is a reg iste red trad emark of Accuphase Labo rato ry, Inc.
＊ HS-LINK cable can be used both for HS-LINK and HS-LINK Ver. 2

signal transmission.

Connection Example: DC-37 has six digital inputs

Performance Graphs

DP-900

HS-LINK cable co nnection
supports transmission of both
SA-CD and CD signals with a
single cable.

Digital inputs

(6 connectors)

HS-LINK

HS-LINK cable

DIGITAL OUT DIGITAL OUT

Coaxial cable

T-1100

Optical fiber cable

DC-37

The DC-37 has a total of six digital inputs that
accept signals from external equipment, such as
for example the DP-900, a computer or other
components. The processor in the DC-37 then
converts these digital data into high-quality music
signals for playback.

◆Front panel

wQuantization bit number

display

q Sampling frequency

display

r

Power switch y Output level control buttons

tInput selector buttons

USB / OPT 1, 2 / COAX 1, 2 / HS-LINK

e

Output level display

DOWN / UP

◆Rear panel

u Digital inputs

HS-LINK / COAXIAL 1, 2
OPTICAL 1, 2 / USB

i Analog outputs

BALANCED / LINE

o Balanced output phase

selector switch

■

Supplied accessories:

●

AC power cord

●

Audio cable with plugs (equivalent to ASL-10, 1 m)

●

“USB Utility 2” CD-ROM (Windows Install Disc)

●

“USB Utility 2”Setup Guide

●

Cleaning cloth

!0AC power connector

USB cable

Analog outputs

(Use either)

Audio cable

Digital component such
as CD transport

＊

USB port

Computer

Analog output

0

〔dB〕

−

20

−

40

−

60

−

80

−

100

−

120

−

140

−

LINEARITY

120−100−80−60−40

Linearity (digital input vs. analog output)

FREQUENCY RESPONSE

100 200

1k 2k 3k 5k 10k 20k

500

Frequency response

＊

For playback of material via
the US B por t, it is necessary
to inst all soft ware fr om the
supp lied “USB Util ity 2 ”
CD-ROM on the c omputer.
(Not required with an Apple
Macinto sh compu ter.)

Preamplifier

〔dB〕

10

8

6

4

2

0

−

2

−

4

−

6

−

8

−

10

20 30 50

DC-37 Guaranteed Specifications 

[Guaranteed specifications measured according to JEITA standard CP-2402A]

● Digital inputs HS-LINK
Suitable cable: Dedicated HS-LINK cable
COAXIAL Format: IEC 60958 AES-3 compliant
Suitable cable: 75-ohm coaxial digital cable
OPTICAL Format: JEITA CP-1212 compliant
Suitable cable: JEITA standard optical fiber cable
USB Format: USB 2.0 Hi-Speed (480 Mbps)
compliant
Suitable cable:

●

Sampling frequencies

HS-LINK 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz,

176.4 kHz, 192 kHz, 352.8 kHz, 384 kHz
(16 to 32-bit 2-channel PCM)

COAXIAL 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz,

OPTICAL 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz
(16 to 24 bit 2-channel PCM)
USB 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz,

(16 to 32 bit 2-channel PCM)

● D/A converter MDSD principle (DSD signal)
MDS++ principle (PCM signal)

● Frequency response  0.5 to 50,000 Hz +0,

Total harmonic distortion 0.0006％ (20 to 20,000 Hz)

●

● Signal-to-noise ratio

119 dB

● Dynamic range 116 dB

● Channel separation 117 dB (20 to 20,000 Hz)

● Output voltage and

BALANCED: 2.5 V 50 ohms, balanced XLR type

impedance LINE: 2.5 V 50 ohms, RCA phono jack

● Output level control

0 dB to -80 dB (digital)

● Sampling frequency / 2-channel PCM
Quantization bit display 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz,

176.4 kHz, 192 kHz, 352.8 kHz, 384 kHz
0 to 32 bit (0 : No data)
2-channel DSD

2.8224 MHz, 5.6448 MHz

★

1 bit

● Power requirements 120 V, 220 V, 230 V AC (voltage as indicated on rear panel),
50/60 Hz

● Power consumption 10 W

● Maximum dimensions Width 465 mm ( 18.31”)
Height 114 mm ( 4.49”)
Depth 385 mm ( 15.16”)

● Mass 14.4 kg (31.7 lbs)

20.0 kg (44.1 lbs) in shipping carton

Connector type: RJ-45

USB 2.0 cable with Type B connector

2.8224 MHz, 5.6448 MHz (1-bit 2-channel DSD)

176.4 kHz, 192 kHz (16 to 24 bit 2-channel PCM)

176.4 kHz, 192 kHz, 352.8 kHz, 384 kHz

2.8224 MHz, 5.6448 MHz (1-bit 2-channel DSD)

3.0 dB

−

−

20

Digital input〔dB〕

〔Hz〕

0

Remarks

★

This produc t is available in ver sions for 120/ 220/230 V AC. Make sure tha t the voltage shown on the rear panel matches the AC line voltage in your area.

★

230 V version has an Eco Mode that switches power of f after 120 minutes of inactivi ty.

★

The shape of the AC inlet and plug of the supplied power cord depends on the voltage rating and destination country.

●

The specifications and appearance of this product are subject to change without notice.

5年間保証

L1405Y PRINTED IN JAPAN 850-2190-00（B1）