Accuphase C 202 Brochure

Page 1

STEREO PREAMPLIFIER

C-ZO

O Cascade class A push»pul| amplifier
0 Separate voltage regulalors for each amplifier unit
0 Balanced input/output circuits

Page 2

CD amplifier features all-stage class A push-pull totally balanced circuit con-
figuration.

Depending on the type and quality of program sources available at a given
time, the demands placed on a control amplifier vary considerably. The
requirements in the present and future age of digital audio for a truly outstand-
ing preamplifier can be stated quite simply: flawless reproduction of high-
quality digital sources such as Compact Discs, and the ability to accommodate
a variety of input combinations.

The Accuphase Stereo Preamplifier 0-202 is a product which perfectly trans-
lates these requirements into reality. One of its most remarkable features is
the totally separate CD amplifier section. Besides the already high-quality
regular line amplifier, this separate circuit has been honed for the ultimate in
performance and quality. The signal path is kept utterly simple, with only a
minimum of functions, for pure, undiluted sound quality. The 0-202 also
provides balanced input and output circuits. In combination with the Balanced
Type Class-A Stereo Power Amplifier P-102, an overall amplifier configuration
with balanced signal lines throughout can be realized, which is a dream come
true for every audiophile

The class-A line amplifier of the 0202 offers a total of 8 inputs, for easy
connection of a variety of program sources. The necessary tape recording and

playback functions are also provided, and all circuits are designed with utmost
regard for sound quality. The left and right channel sections are powered from
separate windings of the power transformer, with discrete rectifier and reg-
ulator circuits for complete channel separation.

in true Accuphase fashion, the entire amplifier is an example of fine craftsman-
ship, and only top-quality materials are used throughout. The sophisticated
front panel is functional and visually pleasing. with less frequently used
controls arranged behind a sub panel. The heavy panel is made from brushed
gold aluminum, and the large knobs are cut from solid aluminum and finished
by a fine sand-blasting process. The side panels of persimmon wood lend a
stunningly beautiful appearance to the amplifier.

Ever since the introduction of the Compact Disc, the opinion was sometimes
voiced that direct connection of the CD player to the power amplifier is the
preferable way to listen to this medium. However, it has been proven many
times that a well»designed preamplifier can further enhance CD reproduction,
by refining the musical quality of the sound and improving the depth of the
sound stage. The preamplifier is also a prerequisite for effectively managing
the ever-increasing number of program sources. The 0-202 was create am
a thorough understanding of these facts. It is a product that fully reflewhe
vast technological expertise and know»how of Accuphase.

Luxurious four-amplifier configuration with
separate UR 6-dBbufieramplifiersforCDand
20-dB line amplifiers

To maintain ultimate purity in Compact Disc
reproduction, the 0-202 incorporates a CD sec»
tion with a buffer amplifier that is completely
separate from the main line amplifier, as shown
in the block diagram of Fig.1 The C-202 may be
thought of as two units in one cabinet: a conven-
tional high-gain preamplifier and a straight-
line" CD buffer preamplifier. The CD amplifier
circuit employs class-A push-pull desrgn
throughout. The CD input signal is supplied
directly to this amplifier and only an absolute
minimum of functions (volume control and
attenuator) are present in the signal path, The
extremely short and simple signal routing en-
sures faithful reproduction of even the most sub-
tle mu3ical nuances and lets the sound stage
unfold with unsurpassed realism. The line am-
plifier also uses a class-A push-pull design for all
stages. While proViding highly pure amplifica-
tion, it is equipped to handle a variety of program
sources and offers the functions required of a
high-class preamplifier.

Balanced cascade class-A push-pull buffer
amplifier for unsurpassed CD performance

As can be seen from Fig. l , the signal path of the
CD section contains only a 720 dB attenuator
and a volume control. nothing else. But the
convenience of tape recording is not lost, as the
CD signalsare also supplied to the tape outputs.
The balanced input and output jacks are an
other important advantage of the CD amplifier
circuit. By connecting a CD player equipped
with balanced outputs to the balanced input of

the 0202, and a power amplifier With balanced
input to the balanced output jacks of the (3-202.
an ideal transmission system as shown in Fig 3
can be configured. Balanced lines are common»
ly used in recording and broadcasting studios.
At the source component, the signal is con-
verted into a posttive and negative signal with
identical voltage potential but phase-inverted by
180 degrees. These two signals are then sent via
a three-conductor cable No current flows in the
ground line, as this connector only serves to link
the zero potential of the signal lines. The receiv»
ing equipment feeds the two Signals to a +
amplifier and a - amplifier and mixes their out-
put. As any noise picked up by the connecting
cable, etc.. has the same phase in both lines, it is
canceled by the mixing process and does not
enter the next stage This ingenious prinCIple
ensures clear and noise-free signal transmis»
sion unobstructed by the adverse effects of
noise induction, Besides the balanced tacks.
two sets of unbalanced connectors (RCA-type
phono jacks) and a headphone output are also
provided.

The basic circuit configuration of the initial arn-
plifier stage. which has a decisive impact on
sound quality. is shown in Fig. 2 The differential
push-pull input circuit receives the balanced
signal. If the unbalanced input is used, the cold
(-) side is connected to ground by a rearrpanel

switch. TranSistors Ola, 02, and 01b. 03 are
cascade-connected respectively the buffer
stage to ensure superior linearity and reSistance
to clipping even With very high input levels.
Transistors 012 7 ms make up the cascode
push-pull driver stage that delivers a clean drive
signal to the output oichits. The well~thought-
out design with meticulous attention to every
detail results in an amplifier that boasts excellent
dynamic range, very lowdistortion. and dramati-
cally improved response characteristics, also in
the extreme upper range beyond the audio
band. As some power amplifiers are not suf-
ficiently sensitive to be driven to full output with
an unampliiied line signal, the CD amplifier was
designed to introduce a 6-dB gain.

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