This is the 4 pages manual for Accuphase E 206 Brochure.
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All direct-coupled circuitry designed with DC servo conﬁguration for straight
and pure signal transmission from MC input to speaker outputs.
Outstanding Low impedance drive capability as low as 2 ohms.
Program sources are getting better all the time. Compact Discs have become an extremely popular
music medium. and Digital Audio Tape as well as digital DBS (Direct Broadcasting Satellite) broadcasts
are quickly catching up. Of course. the playback equipment has to keep pace with these developments,
to let the listener enjoy the full potential of such advanced sources. The E7206 reflects Accuphase‘s long
experience in building separate type amplifiers of world renown. It uses only carefully selected parts
and provides performance and quality which are on a par with standalone preamplifiers and power
The output stage uses wide frequency range output transistors which can handle large currents and are
arranged in a pushapull configuration. The complementary MOS-PET driver circuit developed by
Accuphase ensures stable operation under a wide variety of load conditions. The amplifier delivers 100
watts per channel into 8 ohms (20-20.000 Hz. 0.01% THD). and 140 watts per channel into 4 ohms.
The impedance of a normal loudspeaker varies considerably depending on the frequency. in order to
provide uniform energy to the speaker over the entire audio frequency range. an amplifier must be
capable of delivering stable power also into very low impedances. The low~impedance drive capability
of the E—206 us outstanding, with a comfortable performance margin. A large power transformer with
separate windings for the preamplifier. driver stage and power amplifier stage ensures that even loads
as low as 2 ohms can be driven without problems.
A very attractive feature of the preamplifier section is the Presence Equalizer which allows precise
control of frequency response at four points: 100 Hz. 500 Hz.2 kHz. and 8 kHz. This makes it possible to
introduce just the right amount of tonal compensation whenever desired.
A total of seven inputs accommodate a variety of program sources. These are switched using logic relay
control for optimum performance and long-term reliability.
Preamplifier output and main amplifier input jacks are provided. for additional flexibility. The two
sections of the amplifier can be linked or separated at the simple flick of a switch. permitting use of the E-
206 as separate preamplifier or power amplifier. A phono equalizer section which rivals the best of high-
end preamplifiers. a separate recording selector. as well as many other features make the E-206 an
excellent choice for the discerning music lover.
Completely direct~coupled DC servo
design from phone input all the way
Parallel push-pull output stage and
MOS-FET driver circuit. Large power
supply and output stage effortlessly to the outputs
drive even every low impedance All amplifier blocks. from the phono input for
loads. analog discs up to the output stage. are linked
Fig. 1 shows the circuit diagram of the power
amplifier section. The output stage employs a
parallel push-pull configuration to provide an
ample power output of 100 watts per channel
into 8 ohms. The driver stage is another example
of innovative Accuphase engineering. It uses
MOS-FETs. which are ideal for the driver stage.
where low output impedance and high driving
voltage are essential.
This driver stage. together with the low emitter
resistance in the output stage. provides ex-
tremely high»quality outputwhich is totally free of
The output stage has to deliver the required
energy to the loudspeakers. The impedance of a
speaker varies considerably depending on the
frequency. For example. the actual impedance
of a speaker system having a nominal impe-
dance of 4 ohms may drop to values as low as 2
ohms or less at some frequencies. Therefore.
the power amplifier must be capable of deliver-
ing stable power also into very low impedances.
However. the current flow in a solid-state am-
plifier is reversely proportional to the load impe-
dance. If this current exceeds he limits of the
output devices. the transistors may be de—
stroyed. This is a factor which has severely
restricted the output level at low impedances.
However. the increasing use of digital program
sources has led to a growing demand for am»
plifiers which can supply sufficient power into
The E-206 has a Pc (maximum power dissipar
tion) rating of about 400 watts. sustained by a
large power transformer. This guarantees per»
formance levels not attained by other amplifiers
in this class. The rated output into 4 ohms is 140
watts perchannel, and even 2—ohm loads can be
directly. without any coupling capacitors in the
signal path. This ensures excellent amplification
performance and clean. uncolored sound. Any
possibility of DC drift is effectively precluded by
separate DC servo loops for each unit. resulting
in highly stable operation.
Power transformer with three
separate windings for preamplifier,
power amplifier driver stage. and
output stage. Separate regulator
circuitry for left and right channel.
The power supply of the E-206 rivals that of
separate components in capability and quality.
In order to preclude mutual interference be»
tween the preamplifier section, which handles
very low-level signals. and the power amplifier.
the power supply must be kept separate. In the
E-206. this is achieved by using a large power
transformer which has three separate windings.
one each for the preamplifier. the power am-
plifier driver stage. and the power amplifier out»
put stage. For further improved performance,
the rectifiers and the regulation and filtering
circuitry are kept separate for the left and right
channel, thereby totally preventing interchannel
crosstalk. Absolutely stable operation is
achieved by separate requlator circuitry for the
preamplifier and power amplifier stage.
High-Gain Equalizer Ampliﬁer Circuit Board
I Power Ampliﬁer Unit (Single Channel
PNP output translators
High-performance phono stage
accommodates all MC and MM
Although digital program sources are becoming
ever more popular. the analog record collection
of a true audiophile and music lover is a treasure
he will not easily abandon. The E>206 is de»
signed to provide high-quality reproduction of
analog records as well.
As shown in Fig. 2. the gain of the phono stage is
switchable to match either moving-coil (MC) or
moving~magnet (MM) cartridges. In the MC
position. gain is 60 dB. and in the MM position 30
The input employs low-noise. high»Gm PB \1-
vices in a a—parallel differential circuit withm—
code bootstrap. The circuit is direct-coupled for
superior signalto-noise ratio and stability. The
triple parallel design is perfectly suited to the low
output levels of moving-coil cartridges. as it
keeps residual noise to a minimum.
Straight and short signal paths with
logic relay control
monitoring can degrade high—frequency re—
sponse and impair imaging. in the E-206. all
switching is performed by relays which are
arranged to permit the shortest possible signal
Advanced logic circuits are used to control the
relays and to assure accurate and precise oper-
The relays have twin crossbar contacts plated
with silver paladium alloy for minimum contact
resistance and outstanding long—term reliability.
“Presence Equalizer" offers versatile
controls which permit subtle adjustments of the
reproduced sound can prove very useful.
Graphic equalizers are originally intended for
this purpose, but their great number of controls