● Output stage with 10-parallel push-pull arrangement in each channel delivers ample
power down to extremely low load impedances of 1 ohm ● Amplification stage features
low-noise instrumentation amplifier topology ● Further refined MCS+ circuit ● Current
feedback principle combines excellent sound quality with total operation stability● Bridged connection mode allows upgrading to monophonic amplifier ● 4-stage gain
control ● Newly developed massive toroidal transformer with high power capacity

A Stereo Power Amplifier That Towers Over the Rest

Witness the ultimate in Class
AB topology. Bringing together the best of Accuphase technology and sonic expertise, the P-7300
stands out both in terms of performance and sound quality. The instrumentation amplifier
principle realized in an ideal fully balanced configuration ensures S/N ratio second to none.
Plenty of muscle from the output stage is sustained by a newly developed power supply, resulting
in impeccable speaker drive that opens up a new chapter in the art of music reproduction.

The P-7300 inherits technology features andconcepts of the 40th anniversary commemorativemodel A-200 and subsequent M-6200 and takesthese even further. Some of the highlights are a
drastic reduction in noise and a significant further
improvement of the damping factor. In the finalstage, the parallel configuration of output devices
ensures high current capacity and keeps theoutput impedance of the power amplifier extremely
low. In addition, intensive research has culminatedin an improved NFB loop with remote sensing, andthe use of MOS-FET switches characterized by
low 'on-resistance'. This further improves the ability
to handle any speaker with competence, realizing
constant-voltage drive even with extremely low
load impedances. The guaranteed damping factor
of at least 1,000 demonstrates the impressive
success of this approach. In addition, by further
refining the parallel drive and gain allocation of theinput stage, Accuphase engineers were able topush the noise floor to previously unthinkablelevels, achieving an amazing signal-to-noise ratioof 125 dB at maximum gain and 131 dB at the–12 dB gain setting.
The massive aluminum diecast heat sinks
arranged on the left and right side of the amplifier
are in direct contact with external air to maximize
heat dissipation efficiency. At the same time, they
are integrated with the panel and chassis, resulting
in superior rigidity of construction. The large
analog meters on the front feature a new type ofLED lighting and present an impressive visualappeal that blends perfectly with the traditional
champagne gold coloring of the panel.

Functions and Features
The amplifier offers a choice of line inputs andbalanced inputs that effectively shut out external
noise interference.

Assembly with line and balanced input connectors

The operation mode selector facilitates bi-amping or bridged connection. In bridged mode, theP-7300 turns into a monophonic power amplifiercapable of delivering anamazing 1,600 watts
into 2 ohms.

Operation mode selector

Low-Noise Instrumentation Amplifier Configuration and Further Refined MCS+ Topology■ Low-noise instrumentation amplifier in discrete configuration allows
balanced signal paths

The balanced input stage circuitry features Instrumentation amplifier topology suchas used in high-precision measuring equipment. To achieve ultra low noise, the input
stage gain is set to a high value, which in turn allows using a high power supply
voltage so that distortion at large amplitudes is eliminated. Signal purity is further
elevated by the use of ultimate-quality fully discrete components.

■ Further refined MCS+ topology for even lower noise

Low-noise input assembly

Accuphase's original MCS (Multiple Circuit Summing) principle uses a number of identicalcircuits connected in parallel to achieve superior performance characteristics. MCS+ is afurther refined version of this approach, which extends the parallel operation approach to theclass-A drive stage of the current/voltage converter, thereby further lowering the noise floor.

■ Current feedback circuit topology assures excellent phase characteristics in high range

In the P-7300, the signal current rather than the more conventionally used voltage isused for feedback, as shown in the illustration below (right). Since the impedance at
the current feedback point is very low, there is almost no phase shift. Phase compensation can therefore be kept at a minimum, and a slight amount of NFB results inmaximum improvement of circuit parameters. Operation remains perfectly stablethroughout, which is especially important for a power amplifier that has to handle
signals ranging from minute to highly dynamic levels.
Signal Input Stage

MCS+ circuitry

Power Amplifier Stage++ INPUT

TRANS-IMPEDANCEAMPLIFIER–NFBNETWORK– INPUT+GAIN
CONTROLOUTPUTOUTPUT

CURRENT NFBNETWORKBUFFER+ INPUT–AMPLIFIERCURRENT ADDER–NFBNETWORK– INPUTI/V
CONVERTER

BUFFER+Principle of Instrumentation Amplifier

4-stage gain selector (–12 dB,–6 dB, –3 dB, MAX) directly
controls the gain of the instrumentation amplifier and therefore further minimizes residual noise at lower settings.

The P-7300 features a
newly developed massive high-power toroidaltransformer, enclosed in
an aluminum housingwith excellent thermal
conductivity and superior vibration damping
characteristics.
As in the A-200, two generously dimensioned vibration resistant aluminumelectrolytic capacitors of
56,000 µF each are used,
to provide ample smoothing capacity. The capacitors have been speciallyselected for their excellent
sonic properties.
To reliably protect the speakers
from any risk of damage incase of an amplifier problem
during operation, power
MOS-FET devices with an
on-resistance as low as 0.002
ohms are used. Because these
semiconductor switches do
not have any mechanicalcontact points, there can be no
contact failures and excellent
long-term reliability is assured.

Gain selector

Principle of Current Feedback Amplifier

A phase selector on the rear
panel provides compatibility
and pin 3
with both pin 2type balanced input sources for
maximum flexibility. Normally,
the pin 3 setting is used.
Phase selector switch

Each channel is served by a power unit with bipolartransistors arranged in a 10-parallel push-pull configuration, producing an impressive linear output progression of
800 watts into 1 ohm (music signals only), 500 watts into 2ohms, 250 watts into 4 ohms, and 125 watts into 8 ohms.

Large high-power
toroidal transformer

Bipolar power transistors designed for audio applications

Output power characteristics
1,000899W

900

Filtering capacitorswith high capacitance

800

Output power (W)Ever since the company's founding, Accuphasestereo power amplifiers have always been at thevery forefront of the global high-end audio scene,
blazing a continuous path of technical and sonicinnovation as demonstrated by many products thathave made history. The P-7100 introduced in 2006
was a top-of-the-line stereo power amplifier thatgained overwhelming recognition both in Japanand overseas. Now, nine years later, the P-7300 is
poised to top that achievement, representing a fullmodel change incorporating latest technology andspecially selected ultimate quality parts. The new
product is destined to become another milestone
against which others are measured, offering amusical experience on a whole new plane.

700620W

600800W

500383W

400500W

300200220W
250W

100

MOS-FET switches

Max. output power
Rated output power

125W
8Ω

4Ω
2Ω
Impedance (Ohms)

1Ω

The amplifier is equippedwith large speaker terminals capable of handling even extremely
heavy-gauge speaker
cables. Two sets of terminals are connected inparallel, which is optimal for bi-wiring connections.

larger than conventional units. This results invery low DC resistance and contributes to the improved damping factor.
The implementation of balanced remote sensing
technology using balanced feedback from apoint near the speaker terminals results in lower
impedance and higher damping factor.
Large speaker terminals++ INPUT

Signal Sensing–NFB
NETWORKIn the output circuitry, socalled edgewise coils which
use special copper leads
with a square rather than around profile are used,providing a cross-sectional
area more than three times+

GAIN
CONTROL

POWER
AMP

–

NFB
NETWORK–– INPUT－ GND+GND Sensing

Balanced Remote Sensing

Ultra thick profile edgewise coil

Signal Input StageMCS+ (Multiple Circuit Summing)

Power Amplification Stage
Bipolar Power Transistors+ B1＋Q1Q5Q2Q6+ B2－
Q9Q12Q13Q15

Q17Q19

Q21

Q23

Q25

Q27

Q29

Q31

Q33

NFB
NETWORK

10-PARALLEL
PUSH-PULLBIAS
STABILIZER

GND

NFB
NETWORKGAIN
CONTROLOUTPUTBIAS
STABILIZER

GND

BIAS
STABILIZERNFBNETWORK－

Q3

Q7

Q4

Q8

Q10

Q11

Q14
Q16

Q18

Q20

Q22＋INPUT

Q24

Q26

Q28

Q30

Q32

Q34

B2BIASSTABILIZER

B1DC SERVO

Meter operation selector

The printed circuit boards for signal transmission are made from glass cloth fluorocarbon
resin offering advantages such as low dielectric
constant and minimum loss.

Output stage with 10-parallel push-pull power arrangementof bipolar power transistors mounted directly to large
diecast aluminum heat sink, also comprising MCS+
circuitry and current feedback amplifier. Two completely
identical units arranged at left and right are used.

BIAS
STABILIZER+ INPUTThe peak hold time can be switchedto three seconds or infinite, and themeter operation and illumination
can also be switched on or off.

Power Amplifier Assembly

Circuit Diagram of Power Amplification Circuitry (One Channel)
GAIN < –12, –6, –3 dB, MAX >＋ Signal
Speaker Terminals

The two large analog
power meters arehighly convenient formonitoring outputlevels. The meters
combine peak level
detection with a logarithmic scalethat allows direct reading of levels
over a wide range.

■ Using two P-7300 units, upgrading to bridged operation or bi-amping is possible. ■ In this case, only the LEFT input (BALANCED or LINE) of each unit is used.

Connection example for bridged setup

Connection example for bi-amping setupLeft loudspeaker－●

Right loudspeaker

When the operation selector is set to bridgedmode, the P-7300 becomes a monophonic amplifier with about four times more output power thanin stereo mode. This makes it possible to enjoy
even more dynamic music reproduction.

＋●－ speaker terminals of the P-7300 are not used.
＊The ●

RIGHT ＋LEFT ＋

P-7300 for left channel

LBRIDGE LED
on front panelof both P-7300
units lit

－●

＋－ ●
●
－ ●＋
●
LOW HIGH＋●

P-7300 for right channel

To left channelinput

Right loudspeaker

In a bi-amped setup, the speaker units for theLOW frequency range and HIGH frequency range
are driven by separate amplifiers, for reproduction with further enhanced sound quality.

LEFT ＋

RIGHT ＋To left channel
input

Left loudspeaker－＊A speaker with a built-in crossover network andseparate inputs for LOW and HIGH range is required.

＋－P-7300 for left channel＋－To left channel
input

Mode selector ofboth P-7300 units
set to BRIDGE
position

DUAL MONO
LED on front
panel of bothP-7300 units lit(dB and % scale)❹ Meter operation selector

P-7300 for right channel

Mode selector ofboth P-7300 units
set to DUAL
MONO position❽ Left/right speaker terminals

BRIDGE / DUAL MONO /LINE / BALANCED❺ Power switch

OFF / NORMAL / 3 SEC / ∞＋Rear panel❷ Left/right channel power meters ❸ Function indicator❶ Hold time indicator－R

Preamplifier

Front panel＋To left channel
input

LR

Preamplifier

－ ●＋
●
－ ●＋
●HIGH

LOW

❼ Gain selector–12 dB / –6 dB /–3 dB / MAX❻ Input selector button
LINE / BALANCED(Same output from top row set and bottom row set)

❾ Line inputs
Balanced inputs
Pin ② – , Pin ③ ＋＊Can be switched withphase selector button

AC power supplyconnector ★
Operation mode selector
DUAL MONO / NORMAL / BRIDGE
Balanced input phase selector switch

P-7300 Guaranteed Specifications [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.

800 watts per channel
into 1 ohm (＊)
500 watts per channel
into 2 ohms
250 watts per channel
into 4 ohms
125 watts per channel
into 8 ohms
Monophonic operation 1,600 watts
into 2 ohms (＊)(bridged connection) 1,000 watts
into 4 ohms
500 watts
into 8 ohms
● Total Harmonic
Stereo operation (both channels driven)
Distortion
0.05%
with a 2 ohm load
0.03%
with a 4 to 16 ohm load
Monophonic operation (bridged connection)
0.05%
with a 4 to 16 ohm load
● Intermodulation Distortion 0.01%
Stereo operation(both channels driven)● Frequency Response● Gain● Gain Selection● Output Load impedance

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
28.0 dB (GAIN selector in MAX position)(Stereo/monophonic operation)–12 dB, –6 dB, –3 dB, MAX
Stereo operation:
2 to 16 ohms
Monophonic operation: 4 to 16 ohms

● Damping Factor

1,000● Input Sensitivity (with 8-ohm load, GAIN selector in MAX position)
Stereo operation:
1.26 V for rated continuous average output
0.11 V for 1 watt output
Monophonic operation: 2.52 V for rated continuous average output
0.11 V for 1 watt output● Input Impedance
Balanced: 40 kilohms
Line:20 kilohms● Signal-to-Noise Ratio (A-weighted, input shorted)
125 dB (GAIN selector in MAX position)
131 dB (GAIN selector in –12 dB position)● Output Level Meters– 40 dB to +3.0 dB (indication in dB and %)Logarithmic scale, with illumination off switch and sensitivity
Peak hold time switchable 3 s, ∞● Power Requirements 120/220/230 V AC, 50/60 Hz (Voltage as indicated on rear panel)● Power Consumption

117 watts idle
820 watts in accordance with IEC 60065● Maximum Dimensions Width 465 mm (18-5/16")
Height 238 mm (9-3/8")
Depth 515 mm (20-9/32")● Mass48.6 kg (107.2 lbs) net
58.0 kg (127.1 lbs) in shipping carton＊With music signals only, 1-ohm loads are

permissible for stereo operation and 2-ohm
loads for monophonic operation.

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

Supplied accessory● AC power cord

●The specifications and appearance of this product are subject to change without notice.
L1505Y PRINTED IN JAPAN 850-2195-00（B1）