m Powerful 11-parallel push-pull output stage in each channel delivers
linear power into loads as low as one ohm m Input stage with MCS
topology m Current feedback circuit combines excellent sound quality
with total operation stability m Bridged connection mode allows upgrading
to true monophonic amplifier m Massive Super Ring toroidal transformer
rated for 1.5 kVA m Printed circuit boards made from Teflon materialA stereo power amplifier with impressive punch: 1,000 watts into 1 ohm
MCS technology in input stage improves S/N ratio, distortion ratings andother characteristics. 11 pairs of wide-band high-power transistors in parallelpush-pull configuration for each channel. Power supply with massive 1.5 kVA
toroidal power transformer supports linear power down to impedances as
low as one ohm. Teflon PCBs with low dielectric constant and minimum loss.

Note 1:The output stage uses high-power transistors with a
rated collector dissipation of 150 watts and collector
current of 15 amperes. These devices boast excellent

frequency response, current amplification linearity,and switching characteristics. The transistors arearranged in an 11-parallel push-pull configuration(Figure 1) for ultra-low impedance and mounted on a
massive heat sink made from diecast aluminum. Thisassures effective heat dissipation and allows theamplifier to effortlessly handle very low impedances.
Power linearity is maintained down to loads as low as
1 ohm, which demonstrates the impressive
capabilities of this amplifier.

Low amplifier output impedance

When forming the load of a power amplifier, a loudspeaker generates
a counterelectromotive force that can flow back into the amplifier
via the NF loop. This phenomenon is influenced by fluctuations inspeaker impedance, and interferes with the drive performance of
the amplifier. The output impedance of a power amplifier should
therefore be made as low as possible by using output devices
with high current capability. This absorbs the counterelectromotiveforce generated by the voice coil and prevents the occurrence ofintermodulation distortion.

MCS topology in input stage drastically improves
S/N ratio, distortion, and other characteristics
The input stage features Accuphase's original MCS(Multiple Circuit Summing-up) design. Three separate
Output current (A)Note 2:11-parallel push-pull power unit delivers guaranteedlinear power output of 1,000 watts into 1 ohm, 500
watts into 2 ohms, 250 watts into 4 ohms and 125
watts into 8 ohms

by a massive Super Ring toroidal transformer housed
in a diecast enclosure with directly mounted heatsinks, and by large filtering capacitors. The
transformer is rated for 1.5 kVA, and there are twocapacitors of 56,000 µF each. This assures morethan ample reserves and allows the amplifier tomeet even the most demanding and rapidly
fluctuating power requirements.
The important input stage also has been given due
attention. Another Accuphase innovation called MCS(Multiple Circuit Summing) helps to minimize noise.
Current feedback topology combines total operation
stability with excellent frequency response, while
requiring only minimum amounts of negative
feedback. The material used for printed circuit boards
has a decisive influence not only on electricalcharacteristics but also on the sonic end result.
The P-7000 uses Teflon boards with extremely low
dielectric constant and low loss. The copper foilside of PCBs and all input and output terminals aswell as all major signal carrying points are gold
plated. Balanced inputs help to shut out external
noise. The overall result of these measures is musicalpurity that leaves nothing to be desired.

The P-7000 continues the distinguished design policyof the M-8000. It adds MCS technology in the input
stage and many other refinements. Carefully
selected top quality parts are used throughout. The
design aim was to achieve very low output impedance(Note 1) and constant drive voltage (Note 2). Theend result is a stereo power amplifier that provides
effortless performance and impeccable sound quality.
In the output stage, 11 pairs of high-powertransistors with a rated collector dissipation of 150
watts are arranged in a parallel push-pull
configuration for each channel. The devices aremounted to large heat sinks on both sides of themain chassis for efficient dissipation of thermalenergy generated during operation. As a result, theamplifier is capable of delivering power in a linear
progression towards lower load impedances: 1,000
watts into 1 ohm, 500 watts into 2 ohms, 250 watts
into 4 ohms and 125 watts into 8 ohms. Speakers
with very low impedances as well as speakers whose
impedance fluctuates drastically can also be driven
with ease. By using the P-7000 in bridged mode, it
is possible to create a monophonic amplifier witheven higher power. This performance is sustained

Constant drive voltage principle

Even when the impedance of a load fluctuates drastically, theideal power amplifier should deliver a constant voltage signal tothe load. Figure 2 is a graph plotting the output voltage versuscurrent characteristics. Even when the load changes, the output
voltage remains almost constant, showing linear current
progression. Actual measurement of clipping power at theextremely low load impedance of 1 ohm yields 1,050 watts. At 2ohms, the figure is 606 watts, at 4 ohms 326 watts, and at 8 ohms
170 watts. This demonstrates the impressive performance reservesof this amplifier.

BIAS STABILIZERCIRCUITMCS

Fig. 2 Output power vs. load impedance(output voltage/output current: actual measurements)

REGULATOR+ B1Q19Q21

unit amplifiers for the input signal are connected inparallel, which minimizes noise anddistortion and greatly improves otherperformance parameters as well. This
manifests itself in further improvedsound quality.
+ B2Q15(Multiple Circuit Summing-up)

Q 13
Q1-4

Output voltage (V)* 1-ohm operation possible withmusic signals only

IC1

Q23

Q25

Q27

Q29

Q31

Q33

Q35

Q37

Q39

Q41

Q43

Q17

NFB
NETWORK– INPUT

Q5-8

IC2+–+ INPUT

Q9-12

IC3Q14OUTPUT
BIAS STABILIZER CIRCUIT

Q18
Q20

Q22

Q16

BIAS STABILIZERCIRCUIT

Current feedback circuit topology
prevents phase shifts in highfrequency range

Q24

Q26

Q28

Q30

Q32

Q34

Q36

Q38

Q40

Q42

Q44

– B2

REGULATOR– B1Fig. 1 Circuit diagram of amplifier section (one channel)

The P-7000 employs the original
Accuphase current feedback principle.
At the sensing point of the feedback
loop, the impedance is kept low andcurrent detection is performed. An
impedance-converting amplifier thenturns the current into a voltage to be
used as the feedback signal. Since
the impedance at the current
feedback point (current adder inFigure 3) is very low, there is almost
no phase shift. Phase compensation
can be kept to a minimum, resulting
in excellent transient response andCurrent
adder– Input+ Input
Buffer

I-V
converter
Trans-impedance
amplifierPrinted circuit boards made from Teflon with low
dielectric constant and low loss

Robust power supply with “Super Ring” toroidaltransformer and high filtering capacity

The printed circuit boards for the signal-carrying
circuits are made of Teflon, a glass fluorocarbon
resin material. Teflon has extremely low specificinductive capacity which is desirable for fast signaltransmission. The low dielectric dissipation factor
results in minimal transmission losses. High-frequency
characteristics and heat resistance are also excellent.
For further improved sound quality, the copper foilside is gold plated.

The P-7000 features a massive toroidal power transformer with a maximum rating of 1.5 kVA. The transformer is housed
in a non-resonant
aluminum casefilled with a material that transmits
heat and absorbs
vibrations. This
completely prevents any adverse influenceson other circuitparts. A toroidaltransformer uses
heavy-gauge copper wiring on adoughnut-shapedcore. This resultsin low impedanceand high efficiency, while allowing compact
dimensions.
Two ultra-large aluminum electrolytic capacitors rated
for 56,000 µF each serve to smooth out the pulsating
direct current from the rectifier, providing more thanample filtering capacity.

OutputAmplifierCurrent NFB
networkFig. 3 Principle of current feedback amplifier

superb sonic transparency. Minimal amounts of NFB
are used for maximum effect, providing natural energy
response.
Figure 4 shows
frequency
response fordifferent gain
settings of thec u r r e n t
feedback
amplifier. TheFig. 4 Frequency response with current feedbackg r a p h s (Response remains uniform even when gain changes)
demonstratethat response remains
uniform over a widerange.

* Teflon is a registered trademark of DuPont USA.

n Power amplifier assembly with 11 parallelpush-pull transistor pairs per channel
mounted directly to large aluminum diecast
h e a t s i n k s, M C S c i r c u i t r y, a n d c u r r e n t
feedback amplifierBridged connection allows upgrading to a truemonophonic amplifier with 2,000 watts into 2ohms, 1,000 watts into 4 ohms, and 500 watts
into 8 ohms.
Bridged connection results in a monophonicamplifier with four times the power output
compared to stereo operation. Dynamic powerwith an almost unlimited feel is the result.

n Balanced connection prevents induced noisen PCB copper foil and all major signal pathcomponents are gold-plated
n Large direct-reading analog
power meters
n Oversize speaker terminals
accept also very heavy-gauge
speaker cable

Assembly with meter and protection circuitry

Easy switching between dual mono operation
and bridged connection

Unbalanced and balanced input
connectors

A mode selector on therear panel makes it
simple to switch
between dual mono,
stereo, or bridged
operation.
Large size speaker terminals

Gold-plated parts

n Front panel

High-quality, high-reliability parts

Parallel drive of output devices
Semiconductor devices for high frequency applications usually employ a multi-chip design
where a number of small transistors or FETs are connected in parallel. This approach allowsreducing inherent impedance and residual noise as compared to single device operation. In
other words, linearity is improved. In physical terms, increasing the surface area of the chip
prevents spot overheating by providing better heat dissipation, resulting in more stable operation.
Parallel connection in the output stage of the P-7000 uses a similar principle for distributing
the current, which lets the amplifier easily deal with sudden demands for high current, suchas caused by pulsive source signals. However, a parallel circuit as implemented by Accuphaseis much more than a simple physical connection. Accuphase's extensive know-how gained
through many years of intensive research and experimentation is in evidence here. Careful
control of temperature characteristics, current matching of individual devices, and many otheradvanced measures are implemented. The overall result is minimized distortion at low currents
and improved S/N ratio, which manifests itself as dramatically improved clarity and transparency
at low listening levels. Ample current reserves make it possible to drive even extremely lowloads with effortless authority. No-holds-barred performance and superb sound are the hallmarksof Accuphase amplifiers.

GUARANTEED SPECIFICATIONS

n Rear panel[Guaranteed specifications are measured according to EIA standard RS-490.]m Continuous Average Output Power (20 - 20,000 Hz)
Stereo operation
1,000 watts per channel into 1 ohm (✽)(both channels driven)
0 500 watts per channel into 2 ohms
0 250 watts per channel into 4 ohms
0 125 watts per channel into 8 ohms
Monophonic operation(bridged connection)

0A Power meters(Output indication in dB and %)B Meter operation/illumination switch
ON OFFC Power switch
D Speaker output terminals
E Mode selector
DUAL MONO NORMAL BRIDGEF Unbalanced inputs

0G Balanced inputs
a Groundb Inverted (–)
c Non-inverted (+)
H Input selector
BALANCE UNBALANCEI AC circuit breaker0
J AC input connector0(for supplied power cord)

Remarks
0 This product is available in versions for 120/230 V AC. Make sure that the voltage shown on
the rear panel matches the AC line voltage in your area.
0 The shape of the AC inlet and plug of the supplied power cord, and the circuit breakercurrent rating depend on the voltage rating and destination country.

n Supplied accessories:

2,000 watts into 2 ohms (✽)
1,000 watts into 4 ohms
0 500 watts into 8 ohms
Note: The rating marked (✽) is for music signals only.

m Total Harmonic Distortion

Stereo operation (both channels driven)
0.05%, with 2 ohm load
0.03%, with 4 to 16 ohm load
Monophonic operation (bridged connection)
0.03%, with 4 to 16 ohm loadm Intermodulation Distortion

0.003%m Frequency Response

At rated output: 20 - 020,000 Hz +0, –0.2 dB
At 1 watt output: 0.5 - 160,000 Hz +0, –3.0 dB

m Gain28.0 dB (in stereo and monophonic operation)m Output Load Impedance

Stereo operation:
2 to16 ohms 0 Driving 1Ω loads in stereo operationand 2Ω loads in monophonic operation
Monophonic operation: 4 to16 ohms is possible with music signals only.

m Damping Factor

300 (stereo/monophonic operation)m Input Sensitivity (with 8 ohm load) Stereo operation

1.26 V for rated output
0.11 V for 1 watt output

Monophonic operation 2.52 V for rated output
0.11 V for 1 watt output
m Input Impedance

Balanced: 40 kilohms Unbalanced: 20 kilohms

m Signal-to-Noise Ratio

122 dB at rated output (A-weighted, input shorted)m Output Level Meters

Logarithmic scale, dB/% indicationm Power Requirements

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

125 watts idle
930 watts in accordance with IEC-65

m Maximum dimensions

WidthHeightDepthm Weight

49.5 kg (109.1 lbs.) net
59.0 kg (130.1 lbs.) in shipping carton

465 mm (18-5/16”)
258 mm (10-3/16”)
545 mm (21-7/16”)• AC power cord

• Specifications and design subject to change without notice for improvements.

http://www.accuphase.com/F0310Y PRINTED IN JAPAN 850-0123-00 (AD1)