Accuphase c 280 l brochure

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STEREO PREAMPLIFIE

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O All-stage cascode class A push-pull design and DC servo direct coupling
0 Dual line amplifiers for balanced signal lransmission
0 Totally monophonic construction with two power transformers and Multiple Power Supply principle

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WITNESS THE ULTIMATE PREAMPLIFIER: ALL-STAGE CASCDDE CLASS A PU
DEDICATED VOLTAGE REGULATORS FOR EACH AMPLIFIER UNIT. IDEAL BAL.

The Accuphase model 0-280 which was introduced in 1982 has not only received the three main audio
awards in Japan but has also been acclaimed the world over as one of the finest preamplifiers ever built. it
is widely used as the ultimate reference for critical listening tests and it also has found its way into the
homes of many discriminating music lovers, In the four years since its introduction, the audio world has
been gradually progressing from analog to digital sources, and Accuphase is playing an important part in
this development. We have now undertaken the challenging task to make the best even better and to
introduce a further refined version of our top-of-the-Iine preamplifier. An important new aspect is the line
amplifier configuration which now employs entirely separate units for ideal balanced signal transmission.
The number of inputs has been increased to a total of ten including two balanced inputs. The phono stage
including the MC head amplifierand equalizercircuits is the same as in the 0280, as it reflects many years
of research and experience and represents the absolute state of the art developed by Accuphase, The
principle of balanced signal transmission, which was propagated by Accuphase as early as 1980, has
found its ultimate realization in the C<280L. Transcending the division between analog and digital, this
preamplifier delivers nothing short of perfection for every application and program source. High-end

music reproduction will never be the same.

in each channel, separate amplifier units and
dual volume controls are used for each side of
the balanced signal line. An entirely balanced
system with ideal signal transmission charac-
teristics throughout can be created by connect-
ing equipment with balanced output to the input
of the C-280L and using its balanced output for
connection of the power amplifier. To fully pref
serve the purity and high quality of digital sour-
cos. the Line input has been refined to deliver
unrivalled performance. Another highlight of the
C-280L is its phono stage, which extracts even
the most delicate nuances from analog records,
Especially the MC head amplifier is designed to
provide optimum conditions for cartridges with a
wide range of impedances and output levels.
Basically the C-280L consists of two mono-
phonic amplifier blocks. This design effectively
prevents mutual interference between the two
channels, A total of Six amplifier units are used.
three for each channel, and each unit is en-
closed in athick aluminum housing, resulting in
the best possible performance.

All amplifier stages employ the cascade-con-
nected pushapull drive principle. for outstanding
linearity up to very high frequencies and drasti-
cally improved signal-to-noise ratio. The original
Multiple Power Supply developed by Accuph-
ase delivers highly stable and ample current to
each stage,

As the sound quality of an amplifier depends not
only on its circuit topology but also on the basic
quality all devrces and components, Accuphase
has devoted extensive research efforts to each
and every aspect, extending even to wiring and
plating materials, The combined result of these
efforts is utterly natural and pure muSic repro-
duction,

Externally. the amplifier presents an elegant and
uncluttered appearance, with four main control
knobs arranged in a symmetrical pattern and
less used functions accessible by opening a
sub panel. The massive cabinet made of exquis-
ite persimmons wood also contributes to the
visual appeal and highaquality feel of the am-
plifier which will continue to please its owner
over many years of use,

Balanced line amplifier with dual

amplifier units for ideal signal

transmission characteristics
In professional audio applications, balanced
signal transmission is extensively used. as this
principle offers superior resistance against
common-mode interference (noise). However,
the transformers used in conventional sy s
tended to limit bandwidth and increase r-
tion. In the C-280L, newly developed balanced
input circuits are employed and the hot and cold
signals are amplified by separate amplifier units,
This no-compromise approach assures ideal
performance characteristics.
The block diagram of Fig. 1 shows the signal
transmission principle of the C-280L. As two
balanced inputs are provided, the input selector
also is designed to switch the hot and cold lines
separately. The same applies for the subse-
quent level control, where atotal fourhigh-preci-
sion attenuators (two for each channel) are
operating in conyunction. Each amplifier unit
consists of two exactly identical circuits
arranged in a complementary differential push-
pull configuration for the ultimate in quality