STEREO POWER AMPLIFIER● 6 -parallel push-pull power transistor output stage ● Large output 150 W /8 ohms, 300 W / 4 ohms, 450 W / 2 ohms ● Instrumentation amplifier principle● Current feedback amplification circuits ● Balanced remote sensing ● MCS+ circuit● High damping factor of 800 ● Speaker output protection ● Highly responsive
large-scale power meters ● Support for bi-amping and bridged mode connections

A stereo power amplifier that envelops you in pure music listening
Filled with the highest-quality technologies, the P-4600 Class AB stereo power amplifier provides supreme drivingperformance. The power amp stage features 6-parallel push-pull power transistors, while its rated output of 150 W into 8ohms dwarfs conventional models. Combined with an S/N ratio of 125 dB and a damping factor of 800, it drives large
speakers with ease and creates a rich, deep soundscape. The P-4600 power amplifier extracts the complete breadth ofrecordings, vividly recreating the rush of live performances, and lets you enjoy the very essence of musical performances.

Groundbreaking technology
The P-4600 power amplifier was created by carefully implementing a series of state-of-the-art circuitry and the highest quality materials.
■ Ample output power

Balanced remote sensing improves thedamping factor by feeding back the GND
at the same time as the signal output fromthe speaker terminals.

The 6-parallel push-pull power transistor output
stage produces linear output power of 150 W into
8 ohms, 300 W into 4 ohms, and a massive
450 W into 2 ohms of maximum output power.

Signalfeedback■ High noise suppression performance＋Ideal gain distribution and other sophisticatedtechniques improve noise level suppression by
18% over conventional models.

Poweramplification

Input
−GND
feedback

18% improvement

Conventionalmodels

23.9 μV

Input

Signal sensing point(closest speaker terminal)−＋

GND sensing point(closest speaker terminal)

OutputMCS+ circuitry

Speakerterminals−■ Instrumentation amplifier

Noise level

With balanced circuits in the signal input section, theamplification stage is comprised entirely of an instrumentation
amplifier principle that equalizes impedance on the + and –sides, for excellent external noise suppression, and provides
optimal circuitry for a high-end audio amplifier.

■ High damping factor
With a damping factor of 800, the speakers can be
driven with full control over the counterelectromotive
forces to get the most out of your speakers.

＋+–■ Ideal gain distribution
By achieving a high gain (12.6×) in the signal input section
combined with the already superb noise performancecreates a dramatic reduction in output noise.
Transmission signal

Input
signal+By placing the voltage amplification stage in a
two-parallel circuit layout, the MCS+ (MultipleCircuit Summing-up) circuit theoretically lowers
the noise floor
2-parallel circuit
by about 30%. ＋

19.5 μV

P-4600Input■ MCS+ circuitry■ Balanced remote sensing

12.6×＋–Speakerterminals–−

Outputsignal2×+Inputterminals−+2-parallel circuit layout of MCS+ principle■ Current feedback amplification topology
The current feedback amplification circuit offers
exceptional performance in the high ranges withalmost no impact on the frequency characteristics
even when gain is switched, resulting in naturaland dynamic driving of the speakers.
＋Current
summing

Input−SignalPower
input section amplification section

I-V
converter

BufferBufferOutputCurrent NFBnetwork■ Three-stage Darlington configuration

Output‑The three-stage Darlington configuration that drives the final output stage by a two-stage drive circuit minimizes
any negative influence on the output stage from the counter-electromotive forces of the speakers.

SignalPower
input section amplification section

Signal input section(GAIN 22 dB / 12.6×)

Power amplification section(GAIN 6 dB / 2×)Protection circuitry

MCS＋+ B1+ B2Three-stage Darlington configuration

BIAS+ B2+ B3BIAS

6-parallelpush-pull output stageFilteringcapacitors+ B4

BIAS＋Input- B2GNDGain
Selecter- B1MAX- 3 dB- 6 dB- 12 dB

Feedback Network
DC ServoOutput

BIAS＋−+ B1

GND+ B2−Input

BIAS- B1- B4

BIAS

- B3- B2BIAS- B1- B2

Circuit diagram (one channel)

L ch power
Toroidal transformer
R ch power
amplification section
amplification section

Advanced features■ Large output 150 W / 8 ohms, 300 W / 4 ohms, 450 W / 2 ohms
■ 6-parallel push-pull power transistor output stage■ Instrumentation amplifier principle■ Current feedback amplification circuits■ Balanced remote sensing■ MCS+ circuit■ Three-stage Darlington configuration■ High damping factor of 800■ Meter display selector・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・①■ LINE / BALANCED input switching ・・・・・・・・・・・・・・・・・・・・・・・・・・・②■ 4-step gain control・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・③■ Polarity switching of balanced input connectors・・・・・・・・④■ Support for bi-amping and bridged modes ・・・・・・・・・・・・・・・・⑤■ Ideal gain distribution in the signal input section ・・・・・・・⑥■ Speaker output protection circuit guards against
short-circuiting ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・⑦■ Large speaker terminals connected directly to protection
circuitry・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・⑧■ Highly reliable MOS-FET switches with no mechanicalconnections・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・⑨■ Large, high-efficiency toroidal transformer ・・・・・・・・・・・・・・・⑩■ High-capacity 50,000 μF filtering capacitors ・・・・・・・・・・・・・・⑪■ Aluminum hairline finish top plate ・・・・・・・・・・・・・・・・・・・・・・・・・・・⑫■ High-carbon cast iron insulator feet with superior
damping characteristics・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・⑬■ Large, high-sensitivity power meters ranging from –50 dB・・・⑭■ Power amplification section with a large heat sink ・・・・・⑮⑮Power amplification section①Meter display

selector②Input selector

button③Gainselector④Balanced input

polarity selector⑥Signal input section⑤Operation

selector⑦Protection circuitry⑧Speaker terminals⑨MOS-FET switches⑩Toroidal transformer⑪Filtering capacitors⑫Top plate⑬Insulator feet

⑭Power metersBi-amping Connection

Bridged Connection(High quality performance that eliminates interaction between high and low ranges)(4× greater power output)

R Speaker

L Speaker

L Speaker

Jumperconnection

Jumperconnection

L

R

R

L

Operation
selector

RL

R

P-4600 for L
Input to L

L

R

L

L

R

Operation
selector

P-4600 for R

Input to L

L

R

L

Operation
selectorR(lit)

DUAL MONO
indicator

Speaker output
selector

Meter display
selector

Power meters

Power switch

R

L

P-4600 for R(lit)Operation selector(rear panel)

DUAL MONO indicator(front panel)R

Front Panel
BRIDGE
indicator

L

Both channels
used for DUAL MONO

Preamplifier

BRIDGE indicator(front panel)

LR

Input to L

L

Operation selector(rear panel)Jumpers
removedOperationselector

P-4600 for L

R

PreamplifierR

Input to L

Both channels
used for BRIDGE
LL

RR Speaker

Jumpers
removedRear Panel

Input selector
buttonA/B Speaker Supported spade lug dimensions
Min.
Max.
terminals
7 mm
16 mm(dual system)

Line input
terminals

Input
indicatorsGain
selector

Operation
selector

Balanced input
connectors

Balanced input
polarity selector

AC power
supply connector

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

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

https://www.accuphase.com

J2305Y

850-2239-00（B1） PRINTED IN JAPAN