● Pure Class A operation delivers 100 watts of quality power into 8 ohms ● Two totally identicalpower amplifier units driven in parallel ● 20-parallel push-pull arrangement of MOS-FET devices in
output stage delivers linear high power progression to ultra-low 1-ohm impedance ● Input section
configured as double instrumentation amplifier ● Double MCS+ circuit and current feedback topology
in amplification stage ● Support for bridged use of two A-200 units with even higher output power● Strong power supply with massive high-efficiency toroidal transformer and large filtering capacitors

Eminently capable pure Class A monophonic power amplifier with power MOS-FET technology –Ultra-low-noise double instrumentation amplifier configuration enables fully balanced signal transmission,
augmented by double MCS+ circuit and current feedback topology. Experience astounding S/N ratio and
impeccable sound quality on a level that has to be heard to be believed. A hefty power supply and 20 power
MOS-FETs arranged in a parallel push-pull configuration deliver 1,000 watts (music signal) into an
ultra-low 1-ohm load. Output stage with further lowered impedance results in a damping factor of 1,000.
■ 20-parallel push-pull arrangement of power MOS-FETsdelivers linear power progression: 800 watts (musicsignal) into 1 ohm, 400 watts into 2 ohms, 200 watts
into 4 ohms, or 100 watts into 8 ohms.

Accuphase was founded in 1972 and astonished theaudio world right from the start, with its separate amplifiercombo, the C-200 and P-300 released in the following
year. Ever since, the company has steadfastly pursued
the path of true high-end audio, making uncompromisingquality and exquisite sound reproduction its hallmark.
Sophisticated technology provides the basis for creatingproducts of true value. At Accuphase, innovation goes
hand in hand with reliability, imbuing each product withthe mark of greatness. The long succession of reference
products crafted by Accuphase has found enthusiastic
reception among audiophiles both in Japan and overseas.
The A-200 encompasses Accuphase power amplifierknow-how to the fullest. It is destined to become anothermilestone, taking the art of audio to the next level.

■ Strong power supply with massive high-efficiency toroidaltransformer and two large 100,000 µF filtering capacitors.
■ Printed circuit boards made from glass cloth fluorocarbon
resin with low dielectric constant and minimum loss.
■ Output level indication switchable between 5-digit
numeric readout and 40-point LED bar graph.
● Meter operation and illumination on/off switch● Digital power meter showing true power values, based on
output current detected by a Hall element● Switchable peak hold time: 1 second or infinite

In order to realize ideal speaker drive capability, the A-200
employs a structural design that exceeds even the
M-6000. Two completely separate power amplifier units,each with its own dedicated heat sink on either side of thechassis, are driven in parallel. This completely parallel
configuration allows a significant increase in output
current and results in a power amplifier with extremely low
output impedance. Along with the choice of only the finest
materials and parts, as well as advanced circuit andpattern technology, this has made possible an amazing
damping factor value in excess of 1,000. A pure class A
amplifier consumes a considerable amount of power andtherefore produces thermal energy at all times, whichmeans that the circuitry has to be designed so as toensure problem-free operation in any environment. The
power MOS-FETs used in the A-200 are renowned fortheir excellent high-frequency characteristics and highthermal stability. This allows finely honed control tomaintain the temperature balance between two power
amplifier units, achieving stable operation even when theload and operating conditions change dramatically.

■ Two sets of oversize speaker terminals
accept Y lugs and allow bi-wiring.

Digital power meter/bar graph meterHall elements■ Fully balanced input stage shuts out
external noise interference.

Gain control selector■ Semiconductor (MOS-FET) switch used for protection circuitry prevents
contact problems and ensures long-term reliability. Eliminating
mechanical contacts from the signal path further enhances sound quality.

Meter circuitry/control circuitry
Power Amplification Stage GAIN 6 dB

+ B2

30

+ B3

Q25
Q9

Q17

+ B4

Q41
Q33

＋
PREAMPLIFIER

Q2

Q10

Q37

Q49

Q18

＊ 1-ohm operation possible with music signals only

35

Power MOS-FETs

Biasstabilizer
circuitSuper-heavy-gauge edgewise coil

Input terminals and ultra-low-noise input circuitry

Ultra-low-impedance output
circuit with semiconductor switch

Double MCS+ (Multiple Circuit Summing)

Q1

Mode selector■ Mode selector allows use of two A-200
units for bi-amping or bridged
operation. Bridging enables upgrade toLarge gold-plated speaker terminal cut from solid brassmonophonic amplifier with even higher
power, delivering 1,600 watts into 2 ohms (music signal), 800 watts into 4
ohms, or 400 watts into 8 ohms.

Signal Input Stage GAIN 22 dB
GAIN < MAX, -3, -6, -12dB >100,000 µF filtering capacitors■ 4-stage gain selector (MAX, –3 dB, –6 dB,–12 dB) also minimizes residual noise.

Another outstanding characteristic of the A-200 is its
enormously improved S/N ratio. By adopting theadvanced instrumentation amplifier principle for the input
stage in a double configuration, using only discrete
electronic components instead of ICs, and fine-tuning thegain complement with the following stage, simply
amazing S/N ratings were achieved: 126 dB at the
maximum gain setting and 132 dB with gain set to –12
dB. These represent ultimate values even in theformidable Accuphase lineup.

−

Large toroidal transformer

Q53

Q57

Q61

Q65

Q69

Q73

Q77

Q81

Q85

25

Q42
Q26

FEEDBACKNETWORKBiasstabilizer
circuit＋DC
FEEDBACK
AMP.

−

DC
FEEDBACKAMP.

Biasstabilizer
circuit

−
Q3

Q27
Q11

Q34

Q43

Q38

Q19

Output current (A)Biasstabilizer
circuit＋FEEDBACKNETWORK20NFB
NETWORKGAIN CONTROLCIRCUIT

Q44
Q50

−

Q54

Q58

Q62

Q66

Q70

Q74

Q78

Q82

Q86

PREAMPLIFIER＋+ INPUT

Q4

Q12

B4

Q20

B3

Q28

NFB
NETWORK

＋

B2

Bias
stabilizer
circuit

−

GND

10

OUTPUT

5
Biasstabilizer
circuit

INPUT

15

+ B2

Q13

PREAMPLIFIER

+ B3

Q29

Q5

＋

Q21
Q35

FEEDBACKNETWORK

Q6

Q14

Q39

Q51

Q22

Q59

Q63

Q67

Q71

Q75

Q79

Q83

0
0

5

10

15

20

25

30

Q46

Bias
stabilizer
circuit

Q31

Q7

＋

Q15

Q23

Q16

Q24

Q36

Q47

Q40
Q48
Q52

Q8

Q56

Q60

Q64

Q68

Q72

Q76

Q80

Q84

Q88

B4
B3

Q32
Bias
stabilizer
circuit

45

50(output voltage/output current)Biasstabilizer
circuit−40

Figure 2 Load impedance vs. output power

NFB
NETWORK＋DCFEEDBACK
AMP.

35

Output voltage (V)

Q87

Bias
stabilizer
circuit−

PREAMPLIFIER

Q55

Q30

＋

DC
FEEDBACKAMP.

GAIN CONTROLCIRCUIT

−

+ B4

Q45

−

FEEDBACKNETWORKGNDNFBNETWORK

B2

Figure 1 Circuit diagram of amplifier section

Power MOS-FETs

“The Ultimate Harmony

of Craft and Beauty”

The A-200 is built to excel in every respect. Only the finest
parts and materials, advanced circuit topology, andimpressive looks come together behind the massive
gold-colored faceplate. External heat sinks on both sides
effectively dissipate thermal energy and exemplify the solidbuild quality. Exuding a warm atmosphere, the A-200
combines style and texture, grace and power.

Latest Instrumentation Amplifier Topology and Further Advanced Double MCS+ Circuit
Fully balanced signal paths realized double

Double MCS+ in amplifier stage further

Current feedback assures excellent phase

instrumentation amplifier configuration

improves S/N ratio

characteristics in high range

The A-200 uses the instrumentation amplifier
principle in a dual configuration. This allows
all signal paths from the inputs to the poweramp stage to be fully balanced. The result is
excellent CMRR (common mode rejection
ratio), minimal distortion, as well as superior
performance in all other vital aspects as well.
Noise and other extraneous influences are
virtually shut out, and the use of latest
technology and fully discrete circuitry
contributes to amazingly high S/N ratio. Even
the most minute details are no longer buried
in noise and emerge with utter clarity.

The input stage of the amplifier section features
another Accuphase innovation. Double MCS+
makes ample use of cascode drive circuits anddedicates each component to a clearly definedtask, thereby ensuring stable performance. Fourcircuits for amplifying the input signal areconnected in parallel to keep distortion to aminimum and to further enhance S/N ratio andother parameters. The resulting level of soundquality is simply stunning.

As shown in the illustration, the A-200 uses theoutput signal current rather than voltage for
feedback. Since the impedance at the current
feedback point is very low, there is almost no phaseshift. A minimal amount of NFB therefore results inmaximum improvement of circuit parameters.
Trans-impedance
BufferGAIN < MAX, -3, -6, -12dB >Power Amplification Stage GAIN 6 dB
Double MCS+ (Multiple Circuit Summing)+

OUTPUT
Current adder
BufferNFB
NETWORKGAIN CONTROLCIRCUITNFBNETWORKI -V
converter

Ampliﬁer

Trans-impedance+
10-PARALLEL
POWER
AMP

Power amplifier assembly––+

OUTPUT+-INPUT

BufferCurrent NFB
network

Principle of current feedback amplifier–+INPUT

Ampliﬁer

Current NFB
network

Buffer+INPUT
Signal Input Stage GAIN 22 dB

I -V
converter-INPUT–NFBNETWORKGAIN CONTROLCIRCUITNFBNETWORK+
10-PARALLEL
POWER
AMP

–

–
+

Double Instrumentation Amplifier Principle

Power amplifier assembly with 10-parallelpush-pull power MOS-FET arrangement for
output stage mounted directly to large diecast
aluminum heat sink, also comprising MCS+
circuitry and current feedback amplifier. Twocompletely identical circuits are used.

■ Using four A-200 units, bridged operation or bi-amping is possible. ■ Connect the input signal either to the balanced or the unbalanced inputs.

Example for bi-amping connection

Example for bridged connection
Left speaker

Bridged operation of two A-200 units allows upgrading
to a monophonic amplifier with even higher power.

Right speaker＊ For connecting the SPEAKER●terminals
to each−other, use speaker cable of same grade as for otherspeaker connections.
＊ Mode selector of left channel/right channel q unit: BRIDGE NOR.
Mode selector of left channel/right channel w unit: BRIDGE REV.
Branch output

To LINE "1" input

To BALANCED "1" input

L

L

R

R

−

＋

−

−

＊ The speakers must have a built-in crossover networkand separate inputs for LOW and HIGH range.
＊ Set the mode selector switches of all four units to NORMAL.

＋

Branch output＋

Left-channel unit w

To LINE "1" input

L

To BALANCED "1" input

＋

−

−

＋

−

Left-channel unit q＋ −＋HIGH LOW＋

Left-channel unit w

R

To LINE "1" input

−

＋

−

Right-channel unit q■ Front panel＋ −PreamplifierR

To BALANCED "1" input

Branch output−

Right speaker

L

Preamplifier
To LINE "1" input

Left speaker

HIGH LOW−

Left-channel unit q＋

In a bi-amped setup, the speaker units for the LOW
frequency range and HIGH frequency range are driven
by separate amplifiers, for optimum sound quality.

q＋

Branch output

−

＋

−

Right-channel unit q

Right-channel unit w

w

To BALANCED "1" input＋

Right-channel unit w

eParts selected for high sound quality and high reliability

Major signal path parts are gold-plated

A-200 Guaranteed Specifications[Guaranteed specifications are measured according to EIA standard RS-490.]r■ Rear panelt!0!2 !3 !4q Hold time indicatorw Digital power meter
Bar graph metere Input type indicator
LINE / BALANCED
r Meter selector
OFF / ALL / dB / W
t Digital power meter range buttons
10 W / 100 W / 1000 W
y Power switch
u Hold time selector button
1 SEC /i Input selector button LINE / BALANCED

y

ui o

Push this button to
open the sub panel

!1

!5

★

o Gain selector
MAX / -3 dB / -6 dB / -12 dB!0 Line inputs(One is used for signal pass-through during bridged connection etc.)!1 Speaker terminals (same output at both sets)!2 Mode selector
NORMAL / BRIDGE NOR. /BRIDGE REV.
!3 Balanced inputs(One is used for signal pass-through during bridged connection etc.)
q Ground w Inverted (–) e Non-inverted (+)(Can be changed with phase selector switch !4)!4 Balanced input phase selector switch!5 AC power connector★

● Continuous Average Output Power (20 - 20,000 Hz)
Normal mode
800 watts into 1 ohm (＊)
400 watts into 2 ohms
200 watts into 4 ohms
100 watts into 8 ohms
Bridged mode
1,600 watts into 2 ohms (＊)
800 watts into 4 ohms
(using two A-200 units)
400 watts into 8 ohms
● Continuous Peak Output Power (1 kHz)
1,000 watts into 1 ohm (＊)
630 watts into 2 ohms
360 watts into 4 ohms
180 watts into 8 ohms
Note: Ratings marked (＊) are for music signals only.
● Total Harmonic Distortion 0.05% with a 2-ohm load
0.03% with a 4 to 16-ohm load
● Intermodulation Distortion 0.01%● Frequency Response
At rated continuous average output: 20 - 20,000 Hz +0, -0.2 dB
At 1 watt output:
0.5 - 160,000 Hz +0, -3.0 dB● Gain28.0 dB (GAIN selector in MAX position)● Gain Selection
MAX, -3 dB, -6 dB, -12 dB● Output Load Impedance Continuous output: 2 to 16 ohms
With music signal: 1 to 16 ohms
1,000
● Damping Factor● Input Sensitivity
1.13 V for rated continuous average output(with 8-ohm load)
0.11 V for 1 watt output● Input ImpedanceLine:
20 kilohms
Balanced:
40 kilohms● Signal-to-Noise Ratio 126 dB (GAIN selector in MAX position)(A-weighted, with input shorted) 132 dB (GAIN selector in -12 dB position)
At rated continuous average output● Output Level Meter
Digital meter5-digit indication showing true
power (W)
Range selection 10 W / 100 W / 1,000 W
Bar graph meter Represents output voltage values(dB) using 40 points
Peak hold time
1 second / inﬁnite (selectable)● Display off switch provided● Power Requirements 120/220/230 V AC, 50/60 Hz● Power Consumption 300 watts idle
400 watts in accordance with IEC 60065※ 230 V version has an Eco Mode.
● Maximum Dimensions Width 465 mm (18-5/16") Height 238 mm (9-3/8")
Depth 514 mm (20-1/4")● Mass46 kg (101.4 lbs) net
55 kg (121.3 lbs) in shipping carton

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.
★ 230 V version has an Eco Mode that switches power off after 120 minutes of inactivity.
★ The shape of the AC inlet and plug of the supplied power cord depends on the voltage rating and destination country.

Supplied accessories:• AC power cord●

Specifications and design subject to change without notice for improvements.

http://www.accuphase.com

F1105Y PRINTED IN JAPAN

851-0215-00（B1）