● Output stage with triple parallel push-pull configuration for each channeldelivers high power down to very low impedance loads ● Instrumentation
amplifier principle used in input stage ● MCS+ circuit and current feedback
topology in amplification stage ● Bridged connection mode allows upgrading tomonophonic amplifier ● Strong power supply with massive high-efficiency
toroidal transformer and large filtering capacitors ● 4-stage gain control

Stereo power
poweramplifier
amplifierwith
with impeccable
impeccable performance
performance Instrumentation
Instrumentation amplifier
amplifierprinciple
principle
Stereoin amplification
amplification stagestage allows
allows fully
fully balanced
balanced signal
signal paths.
paths. Further
Further refinedrefined MCS+
MCS+ andand current
current
infeedback topology
topology assure
assure excellent
excellent sound,sound, with
with outstanding
outstanding S/NS/N ratio
ratio andand excellent
excellent perforperforfeedback
mance inin allall otherother aspects.
aspects. AA hefty
hefty power
power supply
supply andand power
power transistorstransistors arranged
arranged inin aa triple
triplemanceparallel push-pull
push-pull configuration
configuration deliverdeliver 500
500 watts/ch
watts/ch (music(music signals)
signals) into
into anan ultra-low
ultra-low 1-ohm
1-ohm
parallelload. Output
Output stagestage with
with further
furtherlowered
lowered impedance
impedance results
results inin aa damping
damping factor
factorofof 500.
500.
load.
Ever since
since its
its founding
founding inin 1972,
1972, Accuphase
Accuphase has
hasEverdesigned its
its power
power amplifiers
amplifiers forfor optimal
optimal speakerspeaker
designed
drive, capturing
capturing thethe high-end
high-end market
market with
with aa successuccesdrive,
sion ofof highly
highly regarded
regarded models
models thatthat became
became legend.
legend.
sion
The commemorative
commemorative model
model A-200
A-200 released
released onon thetheTheoccasion ofof thethe company’s
company’s 40th
40th anniversary
anniversary demondemonoccasion
strated Accuphase’s
Accuphase’s masterymastery ofof power
power amplifier
amplifierstratedtechnology. ItIt stands
stands atat thethe pinnacle
pinnacle ofof its
its field
field and
andtechnology.
hasbeenbeenwidely
widelylauded
laudedasasaahistory-making
history-makingachieveachievehasment both
both inin terms
terms ofof performance
performance andand sonic
sonic
ment
excellence. The
The Stereo
Stereo PowerPower Amplifier
Amplifier P-4200
P-4200excellence.
incorporatesthetheoutstanding
outstandingdesign
designtechnology
technologyofofthe
theincorporates
A-200. Based
Based onon thethe P-4100,
P-4100, itit represents
represents aa full
full
A-200.
modelchangechangewith
withfurther
furtherenhanced
enhancedoverall
overallcircuitry.
circuitry.
model
Latest instrumentation
instrumentation amplifier
amplifier topology
topology isis
Latestimplementedininthe
theentire
entireconfiguration
configurationofofthe
theP-4200,
P-4200,
implemented
allowingnot
notonly
onlyfully
fullybalanced
balancedsignal
signalpaths
pathsfromfromthetheallowing
inputs onwards,
onwards, but
but also
also thethe realization
realization ofof aa gain
gain
inputscontrol thatthat effectively
effectively minimizes
minimizes residual
residual noise.
noise. The
The
controlpower amplifier
amplifier section
section featuresfeatures another
another Accuphase
Accuphase
power
specialty, namely
namely thethe MCS+
MCS+ topology
topology inin combination
combination
specialty,
withcurrent
currentfeedback,feedback,ensuring
ensuringoutstanding
outstandingS/N
S/Nratio
ratio
withand superior
superior electricalelectrical performance
performance characteristics.
characteristics.
andTheoutput
outputstagestageforforeacheachchannel
channeluses
usesthree
threepairs
pairsofofThehigh-power transistorstransistors with
with aa Pc
Pc ratingrating ofof 220
220 watts,
watts,
high-power
arranged inin aa parallel
parallel push-pull
push-pull configuration.
configuration. ThisThis
arrangedensures low
low output
output impedance.
impedance. Stable
Stable operation
operation isis
ensuresachieved by
by mounting
mounting thethe devices
devices toto massive
massive heat
heat
achievedsinks onon bothboth sides
sides ofof thethe chassis,
chassis, forfor efficientefficient
sinks
dissipationofofthermal
thermalenergy.
energy.As
Asdemonstrated
demonstratedby
bythe
the
dissipation
power rating
rating ofof 500
500 watts
watts perper channel
channel into
into 11 ohm
ohm
power
(music signals
signals only),only), thethe P-4200
P-4200 cancan easily
easily drive
drive(musicspeakerswith
withveryverylowlowimpedance,
impedance,and
andspeakers
speakerswith
withspeakers
uneven impedance
impedance curves
curves areare also
also handled
handled with
withunevenaplomb.Using
UsingthetheP-4200
P-4200ininbridged
bridgedmodemodecreatescreatesaa
aplomb.
monophonic amplifier
amplifier with
with even
even more
more impressive
impressive
monophonicpower output
output capability.
capability. This
This kind
kind ofof performance
performance isis
power
sustained byby aa power
power supply
supply section
section with
with aa large
large
sustainedtoroidal transformer
transformer whose
whose efficiency
efficiency has
has been
been
toroidalfurther increased
increased compared
compared toto thethe P-4100,
P-4100, andand twotwofurtherlarge 47,000
47,000 µFµF filteringfiltering capacitors
capacitors selected
selected for
for
large
ultimate soundsound quality
quality andand reflecting
reflecting know-how
know-howultimate
gainedwith
withthetheA-200.
A-200.
gainedThe output
output circuitry
circuitry also
also benefits
benefits fromfrom thethe latest
latestThe
technology advances.
advances. Output
Output relays
relays have
have been
been
technology
replacedby
byMOS-FET
MOS-FETswitches
switchesthat
thatcombine
combineexcellent
excellent
replacedreliability with
with highly
highly pure
pure amplification.
amplification. Redesigned
Redesigned
reliability
output coils
coils andand otherother featuresfeatures result
result inin lower
lower energy
energyoutputlossesandandallow
allowaadrastic
drasticimprovement
improvementofofthe
thedamping
damping
lossesfactor toto 500.
500. This
This rating
rating not
not only
only points
points towards
towards ananfactorextremely wide
wide power
power bandwidth,
bandwidth, itit also
also means
means that
that
extremely
the degree
degree ofof coupling
coupling between
between loudspeakers
loudspeakers andandtheamplifier has
has been
been tightenedtightened even
even further,further, resulting
resulting inin
amplifiermusicplayback
playbackofofimpressive
impressivefidelity.
fidelity.
music■PowerPower modules
modules with
with high-powerhigh-power transistorstransistors inin triple
triple■parallel push-pull
push-pull arrangement
arrangement deliverdeliver linear
linear power
power ofofparallel
500 watts
watts perper channel
channel into
into 11 ohm
ohm (music(music signals
signals only),only),
500
360 watts
watts into
into 22 ohms,
ohms, 180
180 watts
watts into
into 44 ohms,
ohms, or
or 90
90
360
wattsinto
into88ohms.
ohms.
watts
■Large,Large, high-efficiency
high-efficiency toroidal
toroidal transformer
transformer andand two
two■
47,000 µFµF aluminum
aluminum electrolyticelectrolytic capacitors
capacitors selected
selected for
for
47,000bestsonic
sonicperformance.
performance.
best

High-powertransistorstransistorsusedusedininoutput
outputstage
stage
High-power■Output
Output stagestage with
with further
further lowered
lowered impedance
impedance■
realizesdamping
dampingfactor
factorofof500.
500.
realizes■Bridging
Bridgingallows
allowsupgrade
upgradeto
tomonophonicmonophonicamplifier
amplifier■with even
even higher
higher power,
power, delivering
delivering 1,000
1,000 watts
watts
with
into22ohms
ohms(music(musicsignals
signalsonly),only),720
720watts
wattsinto
into44
intoohms,oror360
360watts
wattsinto
into88ohms.
ohms.
ohms,
■InputInput selector
selector button
button on
on front
front panel
panel allows
allows■switchingbetween
betweenLine
LineandandBalanced
Balancedsignals.
signals.
switching

Filteringcapacitors
capacitors
Filtering

Toroidalpower
powertransformer
transformer
Toroidal■4-stage
4-stage gain
gain selector
selector (MAX,(MAX, -3
-3 dB,
dB, -6-6 dB,
dB, -12-12 dB)dB)■
alsominimizes
minimizesresidual
residualnoise.
noise.
also■LargeLarge analog
analog power
power meters
meters with
with on/off
on/off switch
switch■andpeakpeakhold
holdfunction
function(3(3seconds/infinite).
seconds/infinite).
andInputselector
selectorbutton
buttonInput

Gainselector
selector
Gain■Semiconductor
Semiconductor(MOS-FET)(MOS-FET)switches
switchesused
usedforforpropro■
tectioncircuitry
circuitryprevent
preventcontact
contact
tectionproblemsand
andensureensurelong-termlong-term
problems
reliability.Eliminating
Eliminatingmechanimechanireliability.
cal contacts
contacts fromfrom signal
signal path
path
cal
also further
further enhancesenhances sound
sound
also
quality.
quality.

Meterselector
selector
Meter

■Two
Two sets
sets ofof oversize
oversize speakerspeaker■terminalsalso
alsoaccept
acceptYYlugs.
lugs.
terminals
MOS-FETswitches
switches
MOS-FET

Partsselected
selectedfor
forhighhighsoundsoundquality
qualityand
andreliability
reliability
Parts

Largespeakerspeakerterminals
terminals
Large

Signalinput
inputstagestage
SignalAssemblywith
withmetermeterand
andprotection
protectioncircuitry
circuitryetc.
etc.
Assembly

Assemblywith
withlinelineandandbalanced
balancedinput
inputconnectors
connectors
Assembly

Poweramplifier
amplifierstage
stage
Power
MCS+（Multiple（MultipleCircuit
CircuitSumming）
Summing）
MCS+

550
550

512W
512W
500
500

Bias
Bias
stabilizer
stabilizer
circuitcircuit++BB1 1REGULATORREGULATOR

450
450

QQ
11
QQ
99

QQ
1313

++BB2 2

QQ
1717++INPUT
INPUT
＋＋
−−

QQ
77

QQ
1111

QQ
1515

QQ
2525

Bias
Bias
stabilizer
stabilizer
circuitcircuitOUTPUTOUTPUTNFBNFB
NETWORKNETWORKGAINCONTROLCONTROLGAIN
CIRCUITCIRCUIT

500W
500W

400
400

QQ
2727

QQ
2121

QQ
33

NFB
NFB
NETWORKNETWORK

QQ
2323

QQ
1919

OutputOutput power
power (W)
(W)

QQ
55

389W
389W

350
350

360W
360W

300
300

243W
243W

250
250
200
200

Bias
Bias
stabilizer
stabilizer
circuitcircuitNFB
NFB
NETWORKNETWORK

＋＋

Bias
Bias
stabilizer
stabilizer
circuitcircuit

150
150

−−

152W
152W
180W
180W

QQ
2222

QQ
22
QQ
66

QQ
1010

QQ
1414

QQ
88

QQ
1212

QQ
1616

INPUT
INPUT

QQ
2020

QQ
2424

QQ
2626

100
100

QQ
2828

QQ
1818

BB2 2

50
50

90W
90W

QQ
44

Bias
Bias
stabilizer
stabilizer
circuitcircuit

REGULATORREGULATOR

BB1 1

Max.output
outputpower
power
Max.
Ratedoutput
outputpower
power
Rated

8Ω
8Ω

4Ω
4Ω

2Ω
2Ω

1Ω
1Ω

Impedance(Ohms)(Ohms)
Impedance

Figure11 Circuit
Circuitdiagram
diagramof
ofamplifier
amplifiersection
section(one(onechannel)
channel)FigureFigure22 Output
Outputpower
powercharacteristics
characteristics
FigureInstrumentation amplifier configuration and further refined MCS+ topology
Instrumentation amplifier configuration

Further refined MCS+ topology for even

Current feedback principle assures excellent

allows fully balanced signal paths

lower noise

phase characteristics in high range

The newly adopted “instrumentation amplifier”
principle ensures that all signal paths from the
inputs to the power amp stage are fully balanced.

Accuphase’s original MCS (Multiple Circuit Summing)
principle uses a number of identical circuits
connected in parallel to achieve superior performance characteristics. MCS+ is a further refinedversion of this approach. By extending parallel operation to the class-A drive stage of the current/voltage
converter, the noise floor has been lowered further.

As shown in the illustration, the P-4200 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.

Signal input stage

Power amplifier stage++ INPUT–NFBNETWORKNFBNETWORK+

Trans-impedance amplifier
OUTPUT– INPUT–NFBNETWORK–– INPUT+

Instrumentation amplifier configuration

This results in excellent CMRR (common
mode rejection ratio) and minimal distortion.
Another significant advantage is that external
noise and other external
influences are virtually
shut out. The result is a
drastic improvement in
operation stability andreliability.

I/V
converter

Buffer

Amplifier

OUTPUT

Current adder
Current NFB
network

Buffer+ INPUT

Principle of current feedback amplifier

Balanced input phaseselector switch● If the balanced input ofthe preamplifier uses
the “pin w positive”
configuration, thisswitch can be used forproper matching.
■ Power

amplifier assembly with threeparallel push-pull high-power transistor
pairs per channel mounted directly tolarge heat sink, MCS+ circuitry, andcurrent feedback amplifier.

■ You can use two P-4200 units in bridged mode or in a bi-amping setup, for even higher quality. ■ Use the LEFT (BALANCED or LINE) input connectors for both units.

Bi-amping connection example

Bridged connection example
Left speaker

Right speaker

Left speaker

Right speakerIn bridged mode, the P-4200 becomes amonophonic amplifier with even higher
power output (1,000 watts into 2 ohms).

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.
＊ The speakers must have a built-in crossover network＊ The

side speaker terminals of the P-4200
are not used.

and separate inputs for LOW and HIGH range.

LOW

HIGH
RIGHT ＋

RIGHT ＋ＬEFT ＋LOW

ＬEFT ＋HIGH

R

P-4200for leftchannelInput to leftchannelL“BRIDGE” LED on
both P-4200 units
lights up.

RqP-4200for leftchannelInput to leftchannelSet Mode selector
on both P-4200 units
to “BRIDGE”.

Preamplifier■ Front Panel

P-4200for right
channelInput to leftchannel

R

L

L

L

P-4200for right
channelInput to leftchannelR

Preamplifier

Set Mode selecto r
on both P-4200 units
to “DUAL MONO”.

P-4200 Guaranteed Specifications

w[Guaranteed specifications are measured according to EIA standard RS-490.]● Continuous Average Output Power (20 - 20,000 Hz)

Note: Load ratings marked (＊) apply only to operation with music signals.

e■ Rear Panel

r

t

i

y

u

!2

Stereo operation (both channels driven)
500 watts per channel into 1 ohm (＊)
360 watts per channel into 2 ohms
180 watts per channel into 4 ohms
90 watts per channel into 8 ohms
Monophonic operation (bridged connection)
1,000 watts into
2 ohms (＊)
720 watts into
4 ohms360 watts into
8 ohms● Total Harmonic Distortion
Stereo operation (both channels driven)
0.05% with 2 ohm load
0.02% with 4 to 16 ohm load
Monophonic operation (bridged connection)
0.05% with 4 to 16 ohm load
● Intermodulation Distortion● Frequency Response

0.01％
At rated 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 (with GAIN selector at MAX)(in stereo and monophonic operation)● Gain Selection

MAX, −3dB, −6dB, −12dB● Output Load impedance

Stereo operation:
2 to 16 ohms
Monophonic operation: 4 to 16 ohms

● Damping Factor

500 (stereo operation)

With music signals only, 1-ohm loads are permissible forstereo operation and 2-ohm loads for monophonic operation.

● Input Sensitivity (with 8-ohm load, GAIN selector in MAX position)
Stereo operation:
1.07 V for rated output
0.11 V for 1 watt output
Monophonic operation:
2.14 V for rated output
0.11 V for 1 watt output

o

!0

!1

q Right/left-channel output power meters(dB and % scale)w Function indicators
SPEAKER A, B / LINE / BALANCED / BRIDGEe Meter switch
OFF / NORMAL / 3 SEC / ∞r Speaker selector buttons
A：ON/OFF / B：ON/OFFt Power switch
y Input selector button
LINE / BALANCED
u Gain selector
MAX / −3dB / −6dB / −12dB!3★
i Line inputs
o Balanced inputs
Pin w: Inverted (-) Pin e: Non-inverted (+)(Can be changed with phase selector
switch !1.)
!0 Mode selector
DUAL MONO / NORMAL / BRIDGE!1 Balanced input phase selector switch!2 Right/left-channel speaker output terminals
A and B (two pairs)!3 AC power supply connector ★

● Input Impedance

Line: 20 kilohms, Balanced: 40 kilohms● Signal-to-Noise Ratio (A-weighted, input shorted)
120 dB (GAIN selector at MAX)
125 dB (GAIN selector at −12 dB)
At rated output● Output Level Meters−∞ dB to +3 dB (indication in dB and %)Logarithmic scale, with defeat switch, hold time switchable 3 s / ∞● Power Requirements

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

76 watts idle
560 watts in accordance with IEC 60065● Maximum Dimensions

Width 465 mm (18-5/16")
Height 190 mm (7-1/2")
Depth 427 mm (16-13/16")● Mass28.9 kg (63.7 lbs) net
35.0 kg (77.2 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 accessory:• AC power cord●

Specifications and design subject to change without notice for improvements.

http://www.accuphase.com

G1305Y PRINTED IN JAPAN

850-2180-00（B1）