m Powerful 11-parallel push-pull output stage in each channel delivers linear
power into loads as low as one ohm m Instrumentation amplifier type designof amplification stages m Further refined MCS+ circuit topology m Current
feedback circuit combines excellent sound quality with total operation stability
m Bridged connection mode allows upgrading to true monophonic amplifier
m 4-step gain control m Massive Super Ring toroidal transformer rated for 1.5 kVAImpressive power amplifier capable of delivering 1000 watts × 2 into 1 ohm –Amplification stages feature fully balanced signal paths as found in highquality instrumentation amplifiers. Further refined MCS+ topology and current feedback design result in even better S/N ratio, distortion, and otherperformance parameters. Massive, high-efficiency 1.5 kVA toroidal transformer and 11-parallel push-pull arrangement of high-power transistors deliver enormous amounts of linear power into ultra-low loads down to one ohm.
The P-7100 is a successor to the highly regarded
P-7000, inheriting its general design policy and major
features while realizing further improvements in various aspects. A major new highlight is the overall “instrumentation amplifier” configuration, which allows
fully balanced signal transmission in all stages of
the amplifier. In addition, the power amplifier section
employs MCS+, an improved version of the innovative Multiple Circuit Summing principle developed byAccuphase. In conjunction with the famous current
feedback topology, this provides further improved
performance characteristics. Only strictly selected
high-quality parts and materials are used throughout,and the output of the amplifier is designed to achieve
very low impedance and constant drive voltage.
In the output stage, 11 pairs of high-power transistors
with a rated collector dissipation of 150 watts are arranged in a parallel push-pull configuration for eachchannel. The devices are mounted to large heat sinks
on both sides of the main chassis for efficient dissipation of thermal energy generated during operation.
As a result, the amplifier is capable of delivering
power in a linear progression down to an ultra-low
load impedance of one ohm. Even speakers with very
low impedances as well as speakers whose impedance fluctuates drastically can be driven with ease.
By using the P-7100 in bridged mode, it is possible
to create a monophonic amplifier with even higher
power. This performance is sustained by a massive Super Ring toroidal transformer housed in analuminum enclosure with excellent heat dissipation
characteristics. The transformer is rated for 1.5 kVA,and is coupled with two large filtering capacitors rated
for 56,000 µF each. This allows the amplifier to meeteven the most demanding and rapidly fluctuating
power requirements with ease.
The input stage features another Accuphase innovation called MCS+ (Multiple Circuit Summing)
which helps to minimize noise. The material used
for printed circuit boards has a decisive influence not
only on electrical characteristics but also on the sonicend result. The P-7100 employs Teflon boards withextremely low dielectric constant and low loss. The
copper foil side of PCBs and all input and output terminals as well as all major signal carrying points aregold plated. Balanced inputs help to shut out externalnoise. The combination of outstanding circuit design
with top-quality materials and parts produces musicof unsurpassed purity that immediately captures andenchants the listener. Hearing is believing.

n 11-parallel push-pull power unit delivers guaranteed linear
power output of 1000 watts into 1 ohm (music signals only),
500 watts into 2 ohms, 250 watts into 4 ohms and 125 watts
into 8 ohms
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.

High-power transistorsn Printed circuit boards made from Teflon with low
dielectric constant and low loss
* Teflon is a registered trademark of DuPont USA.

n Robust power supply with Super Ring toroidaltransformer and high filtering capacity
The P-7100 features a massive toroidal power transformer
with a maximum rating of 1.5 kVA, and two large electrolytic
capacitors rated for 56,000 µF each, specially selected for
optimum sound quality.

Toroidal transformer

Filtering capacitors

n Bridged connection allows upgrading to a true monophonic amplifier with 2000 watts into 2 ohms (music signals only), 1000 watts
into 4 ohms, and 500 watts into 8 ohms
Bridged connection results in a monophonic amplifier with four times the power
output than during stereo operation. This gives effortless dynamic power.

n Balanced inputs prevent externally induced noisen 4-step gain selector minimizes residual
noise (MAX, –3 dB, –6 dB, –12 dB)

Unbalanced/balanced input connectors

n PCB copper foil and all major signal
path components are gold-plated
n Mode selector makes it easy to switch
between dual mono, stereo, or bridged
operationn Large direct-reading analog power
meters with meter on/off button

Gold-plated parts

Gain selector

n Input selector button (balanced/unbalanced) on front paneln Oversize speaker terminals accept also Y lugs
Meter and input selector buttons

Large speaker terminals

Highly reliable parts selected forsound quality

Assembly with meter and protection circuitry

MCS+Circuit(MultipleSumming )Bias stabilizer
circuit

REGULATOR+ INPUT

Bias stabilizer
circuitNFB
NETWORKGAIN CONTROLCIRCUIT
Bias stabilizer
circuitOUTPUT

Bias stabilizer
circuitNFB
NETWORKOutput current (A)NFB
NETWORK– INPUT

Output voltage (V)REGULATOR
Bias stabilizer
circuitFigure 1 Circuit diagram of amplifier section (one channel)* 1-ohm operation possible withmusic signals only

Figure 2 Load impedance vs. output powe(output voltage/output current)Instrumentation Amplifier Principle and Further Refined MCS+ Topology
Instrumentation amp configuration allows
fully balanced signal paths

Further refined MCS+ topology for evenlower noise

Current feedback circuit topology assures
excellent phase characteristics in high range

The amplifiation sections of the P-7100 feature thenewly adopted “instrumentation amplifier” principle
whereby all signal paths from the inputs to the poweramp stage are fully balanced.
This results in excellent CMRR (Common Mode

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 refined

In the P-7100, the signal current rather than themore conventionally used voltage is used for feedback. Since the impedance at the current feedbackpoint is very low, there is almost no phase shift.
Phase compensation can therefore be kept at aminimum. A slight amount of NFB results in maximum improvement of circuit parameters.

Signal input stage

Power amplier stage+ INPUT(–) input buffer

NFB
NETWORKGAIN CONTROLCIRCUITOUTPUT

Current
adder

I/V
converter
Trans-impedance
amplifierAmplifier(+) input buffer
NFB
NETWORK– INPUT

Instrumentation amplier conguration

Rejection Ratio) and minimal distortion. Anothersignificant advantage is that external noise andother external influences are virtually shut out. The
result is a drastic improvement in power amplifier
operation stability and reliability.

version of this approach. Improvements in the bias
circuitry of the input-stage buffer amplifier result ingreater stability. This in turn makes it possible
to extend the parallel operation approachto the class-A drive stage ofthe current/voltage conver ter, thereby fur ther lowering
the noise floor.

n Power amplifier assembly with 11 parallel push-pull transistor
pairs per channel mounted directly to large aluminum diecast
heat sinks, instrumentation amplifier and MCS+ circuitry, andcurrent feedback amplifierrCurrent NFBnetwork

Principle of current feedback amplifier

OutputConnection example for bi-amping setup
Left loudspeaker

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

Right loudspeaker

Connection example for bridged setup
Left loudspeaker

Right loudspeakerIn bridged mode, the P-7100 becomes amonophonic amplifier with even higher
power output.

A speaker with a built-in crossover networkand separate inputs for LOW and HIGH range
is required.
Two P-7100 units are required.

P-7100 for
left channel

For stereo operation, two P-7100 units arerequired.

P-7100 forright channel

Mode selector of
P-7100 (DUAL
MONO position)

P-7100 for
left channelm Use the LEFT (BALANCED or
UNBALANCED) input connectors
for both P-7100 units.

P-7100 forright channel

Mode selector of
P-7100 (BRIDGEposition)

Preamplifiern Front Panelm Use the LEFT (BALANCED or
UNBALANCED) input connectors
for both P-7100 units.

Preamplifier

Parallel drive of output devices
Semiconductor devices for high frequency applications usually employ a multi-chip design where a numberof small transistors or FETs are connected in parallel. This approach allows reducing inherent impedance
and residual noise as compared to single device operation. In other words, linearity is improved. In physicalterms, 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-7100 uses a similar principle for distributing the current, whichlets the amplifier easily deal with sudden demands for high current, such as caused by pulsive source signals.
However, a parallel circuit as implemented by Accuphase is much more than a simple physical connection.
Accuphase’s extensive know-how gained through many years of intensive research and experimentation isin evidence here. Careful control of temperature characteristics, current matching of individual devices, andmany other advanced measures are implemented. The overall result is minimized distortion at low currents andimproved 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 low loads with effortless authority.
No-holds-barred performance and superb sound are the hallmarks of Accuphase amplifiers.

P-7100 Guaranteed Specifications[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)
500 watts per channel into 2 ohms
250 watts per channel into 4 ohms
125 watts per channel into 8 ohms

n Rear Panel

Monophonic operation(bridged connection)

2,000 watts into 2 ohms ( )1,000 watts into 4 ohms
500 watts into 8 ohms
Note: Load ratings marked ( ) apply only to operation with music signals.
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 0.01%
m Frequency Response

At rated output: 20 - 20,000 Hz
At 1 watt output: 0.5 - 160,000 Hzm Gain

28.0 dB (with GAIN selector at MAX)m Gain selection

MAX, –3 dB, –6 dB, –12 dB

m Output Load impedance

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

m Damping Factor

300

m Input Sensitivity(with 8-ohm load)

Stereo operationm Input Impedance
Input type indicators
Power meters (dB and % scale)
Bridged mode indicator
Meter operation/illumination switch
Input selector button
BALANCED UNBALANCEDPower switch
Gain selector
MAX –3 dB –6 dB –12 dB
Speaker terminals

Unbalanced inputs
Balanced inputs
 Ground  Inverted (–)
 Non-inverted (+)
Mode selector
DUAL MONO NORMAL BRIDGE
Circuit breakerAC power supply connector

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

m Signal-to-Noise Ratio(A-weighted, input shorted,
At rated output)+0, –0.2 dB+0, –3.0 dB

With music signals only, 1-ohm loads
are permissible for stereo operation and2-ohm loads for monophonic operation.

1.26 V
0.11 Vfor rated output
for 1 watt output

Monophonic operation 2.52 V
0.11 Vfor rated output
for 1 watt output

Balanced:
Unbalanced:

40 kilohms
20 kilohms

122 dB (GAIN selector in MAX position)
127 dB (GAIN selector in -12 dB position)m Output Level Meters

Logarithmic scale, with defeat switch–60 dB to +3 dB (indication in %)m Power Requirements

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

135 watts idle
945 watts in accordance with IEC-60065

m Maximum dimensions

465 mm (18-5/16”) width
258 mm (10-3/16”) height545 mm (21-7/16”) depthm Mass49.0 kg (108.0 lbs.) net
58.0 kg (127.9 lbs.) in shipping cartonn Supplied accessory
m AC power cordm Specifications and design are subject to change without notice for improvements.

http://www.accuphase.com

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