Page 1
Featuring further improved MCS topology in preamplifier and power amplifier
sections -“
Enjoy total sonic realism emerging from a background of utter
silence. Wide-band power transistors in parallel push-pull configuration,
working in conjunction with the rugged power supply deliver plenty of quality
power: 115 watts per channel into 4 ohms or 90 watts into 8 ohms. Option
board slot can be used to implement digital signal input for even better CD
reproduction or analog record playback with impeccable quality.
The integrated amplifier series E-200 enjoys an
enviable reputation, both in Japan and abroad. The
E-213 embodies the sophisticated design concept
of this series while featuring latest circuit topology
and top quality materials. This results in further
improved sound from an integrated amplifier that
excels in all aspects. It brings out the inherent
qualities of the source with total fidelity. Embark on
a journey of musical discovery and discover the
sheer beauty of sound.
An integrated amplifier offers various advantages
such as convenient operation and modest space
requirements. However, because its overall gain is
very high, even the slightest interference or crosstalk
at the input can have a considerable effect on the
sonic result. To preclude this possibility, the E-213
is designed to achieve total electrical and structural
separation of the preamplifier and power amplifier
sections. These two parts operate as if they were
entirely separate components, which significantly
enhances the purity of sound. An EXT PRE switch
and dedicated inputs even allow independent use
of the power amplifier section.
Both the preamplifier and power amplifier use the
proprietary MCS (Multiple Circuit Summing)
principle developed by Accuphase, which
significantly improves S/N ratio and other vital
parameters. In addition, the power amplifier section
incorporates the highly acclaimed current feedback
topology from Accuphase. This ensures excellent
phase characteristics in the high frequency range,
combining total operation stability with outstanding
frequency response.
The power amplifier output stage adopts a parallel
push-pull configuration of multi-emitter power
transistors designed for high-power audio
applications. The large power transformer in the
power supply and plenty of filtering capacity sustain
ample high-quality output power. The preamplifier
section comprises features such as tone controls,
loudness compensator, and facilities for recorder
connection. Each circuit component has been
carefully selected after extensive tests. The end
result is an integrated amplifier that clearly stands
Q11 Q13
Q12 Q14 Q10
Q8
Q6
Q5
Q7
Q9
+-“
OUTPUT INPUT
-“ B1
+B1
-“ B2
+B2
REGULA-
TOR
REGULA-
TOR
NFB
NETWORK
Q1a
Q3a
Q2a Q4a
Q1b
Q3b
Q2b
Q4b
REGULA-
TOR
REGULA-
TOR
REGULA-
TOR
REGULA-
TOR
BIAS STABILIZER
CIRCUIT
OUTPUT INPUT
BufferCurrent
adder
converter
Trans-impedance
amplifier
Amplifier Output
Current NFB
network Input
Gain(Large)
(High)
Frequency
out from the rest. An option board can be used to
implement digital inputs or high-quality analog
record playback.
Accuphase proprietary MCS topology in
preamplifier and power amplifier stages
Both the preamplifier and power amplifier employ
the MCS (Multiple Circuit Summing) topology
developed by Accuphase. This design results in
significantly improved performance characteristics
such as higher S/N ratio and lower distortion. In the
power amplifier section (Figure 1), the same signal
is supplied to two separate circuits, which also
receive the feedback signal. After amplification, the
output is then combined. In the preamplifier (line
amplifier) as shown in Figure 2, a complete MCSconfiguration is adopted with fully
parallel operation of the entire
amplification chain, not only a part of the
stage. Mathematically, when using two
parallel circuits, the improvement in S/N ratio
is a full 3 dB.
Parallel push-pull power amplifier units deliver
quality power: 115 watts/channel into 4 ohms
or 90 watts/channel into 8 ohms
The output devices are multi-emitter power
transistors designed for high power audio
applications. These devices have excellent
Fig. 1 Circuit diagram of power amplifier (one channel)Fig. 2 Circuit diagram of line amplifier (one channel)
Fig. 3 Principle of current feedback amplifier
Fig. 4 Frequency response with current feedback(Response remains uniform also when gain changes)
frequency response, forward-current transfer ratio
linearity, and switching performance characteristics.
They are connected in a parallel push-pull
configuration and mounted directly on a large heat
sink to assure efficient dissipation of thermal energy.
Current feedback circuit topology in the power
amplifier section prevents phase shifts and
assures excellent sound quality
In the power amplifier section of the E-213, the
signal current rather than the more
conventionally used voltage is used for
feedback. Because there is almost no
phase shift, phase compensation can be
kept to a minimum, resulting in excellent
transient response and superb sonic
transparency. Furthermore, frequency
response remains unchanged even when
gain changes.
Figure 4 shows frequency response
curves for different gain settings of the
current feedback amplifier. It is evident
that characteristics remain uniform over
a wide range.
High-power transistors
Page 2
F1
A1 A2
VR1
F2
VR2
OUTPUT
INPUT
Fig. 5 Tone control circuit principle
(Summing active filter type)
Power amplifier assembly
with parallel push-pull output
devices mounted to large heat
sink, MCS circuit, and current
feedback amplifier circuitry
n nn n
nSupplied remote commander RC-23
Allows volume adjustment and input
source switching
Highly reliable logic-controlled relays for best
sound quality
Program source switching is performed by logic-
controlled relays which are arranged so as to permit
straight and short signal paths for enhanced sonic
purity. The hermetically sealed relays are high-
quality types developed specifically for demanding
communication applications. The contacts are twin
crossbar types plated with gold for minimum contact
resistance and outstanding long-term reliability.
Tone controls use summing active filters for
pure sound
The tone control circuitry in the E-213 features sum-
ming active filters. Figure 5 illustrates the operation
principle of this circuit. The flat signal is passed
straight through, and only when an adjustment is
required,
the charac-
teristics cre-
ated at F
1 and F 2 are
added to the
signal,
thereby pro-
ducing the
desired
change.
This design
provides efficient control without degrading signal
purity.
Gold-plated input/output jacks
connected directly to relays
Large power transformer and high filtering
capacity
The E-213 features a
large power trans-
former with a rating of
400 VA. The trans-
former is mounted in
an enclosure filled
with damping material
that has excellent
heat transfer charac-
teristics. This design
prevents unwanted
interaction with the
rest of the amplifier.
Two massive electro-
lytic capacitors, each
rated
for 22,000 µF,
are used to filter the
current. This ample
performance margin
of the power supply
ensures dynamic sound down to very deep frequen-
cies.
EXT PRE switch and power amplifier inputs
allow separate use of power amplifier section
The preamplifier section
and power amplifier section
are designed as separate
entities. A convenient EXT
PRE switch and dedicated
inputs make it easy to use
the power amplifier of the
E-213 on its own.
Two sets of heavy-duty speaker terminals
Two sets of
oversize
speaker
terminals are
provided which
accept also
heavy-gauge
speaker cable.