Accuphase E-450 Brochure
m Revolutionary AAVA-II volume control m Parallel push-pull
output stage with high-power transistors delivers plenty of quality
power m Instrumentation amplifier principle enhances current
feedback and MCS+ topology in power amplifi er section m Logic-
control relays for straight and short signal paths m Robust power
supply with large toroidal transformer and high filtering capacity
High-class integrated amplifi er with 180 watts per channel (8 ohms) – Innovative AAVA-II volume control opens up new musical frontiers. High-power
transistors operate in a parallel push-pull arrangement. Power supply with
large, highly effi cient toroidal transformer and oversized fi ltering capacitors
sustains ample power. Instrumentation amplifi er confi guration in power amplifi er makes optimum use of current feedback design combined with further improved MCS+ topology, resulting in excellent high-range phase characteristics.
The E-450 succeeds the highly popular and
successful Accuphase model E-408. It refl ects
latest research breakthroughs and features
the innovative AAVA-II volume control principle. Only top-quality parts are used throughout
its sophisticated circuitry. The overall result is
an integrated amplifi er that brings out even
the most delicate nuances in the music with
breathtaking immediacy.
The AAVA volume control principle developed
by Accuphase totally revolutionizes the way
that the listening volume is adjusted. However,
in its initial form, AAVA required a considerable amount of physical space. With AAVA-II,
Accuphase has now taken this principle to the
next level, delivering the same peerless performance in a more compact form factor. This
was made possible by implementing highly
sophisticated surface mount technology while
increasing component density and integration
and optimizing the layout. With AAVA-II, amplifi cation and volume control are fully integrated.
The use of highly reliable electronic components eliminates mechanical wear and associated problems, allowing the control to function
perfectly for many years.
Because an integrated amplifi er has very high
overall gain, even the slightest interference or
crosstalk at the input can have a considerable
effect on the signal provided at the output. To
preclude this possibility, the E-450 is built with
totally separate preamplifi er and power ampli-
fi er sections. Both electrically and structurally,
these two parts operate completely autonomously. A set of EXT PRE inputs and outputs
allows using the preamplifi er and power ampli-
fi er separately. In terms of performance quality,
the E-450 can hold its own even when compared with stand-alone components.
The power amplifi er section is built as an
advanced instrumentation amplifi er, which
enables fully balanced signal transmission
throughout. Together with further improved
MCS+ circuit topology and the highly acclaimed current feedback principle, this makes
for even better electrical characteristics. In the
output stage, high-power transistors designed
for audio applications are arranged in a parallel
push-pull confi guration, greatly improving the
capability of the amplifi er to drive low imped-
ance loads.
n Parallel push-pull power amplifi er unit achieves 180 watts
per channel into 8 ohms or 260 watts into 4 ohms.
The output stage devices feature excellent frequency response, current
amplifi cation linearity, and switching characteristics. These high-power
transistors have a rated collector dissipation of 220 watts.
n Instrumentation amplifi er principle in power amplifi er section
allows fully balanced signal paths. Current feedback design
ensures outstanding high-range phase characteristics together with further
improved MCS+ topology.
n Massive high-effi ciency toroidal transformer and large fi ltering capacitor
selected for sound quality provide ample reserves.
n
Logic-controlled relays assure high sound quality and long-term reliability.
n Tone controls using active fi lters for optimum sound quality.
n Loudness compensator for enhanced bass at low listening
levels.
n E-450 front panel switching enables MC/MM selection for
optional Analog Disc Input Board AD-20.
n “ EXT PRE” button and preamplifi er output/power amplifi er
input connectors allow independent use of preamplifi er and
power amplifi er sections.
n Dedicated headphone amplifi er delivers audiophile quality
sound.
n Analog peak power meters for monitoring output levels.
“MC/MM” Selector
“EXT PRE” button
n Two sets of large-size speaker terminals.
n “High Carbon” cast iron insulator feet further enhance sonic
purity.
n Versatile array of inputs with balanced connectors to shut out external
noise interference.
Unbalanced input/output jacks and balanced input connectors
High-reliability parts selected for sound quality
High-power transistors
Toroidal power transformer
Filtering capacitors
Large speaker terminals
INPUT
+
–
NFB
NETWORK
NFB
NETWORK
–
+
MCS+ (Multiple Circuit Summing-up)
Bias
+B3
–B3
stabilizer
Q
1
Q
Q
Q
3
stabilizer
stabilizer
Q
2
Q
Q
Q
4
stabilizer
Q
5
7
Bias
Bias
6
8
Bias
9
Q11Q
Q10Q
Q12Q
Q
13
15
14
16
REGULATOR
Q
17
stabilizer
Q
18
Bias
NFB
NETWORK
REGULATOR
Q
19
Q
20
Circuit diagram of E-450 power amplifi er
(one channel)
+B1
Q
21
Q
22
–B1
+B2
Q
23
OUTPUT
Q
24
–B2
Output stage and power amplifi er assembly
n
with parallel push-pull devices, MCS+ circuit
and current feedback circuitry mounted to
large heat sink
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