Accuphase C 222 Brochure

Page 1

STEREO PREAMPLIFIER

(3-222

0 Built-in mum-function head amp
0 All stages push-pull. DC servo direct coupled O Mulliple power supply

SCEFCO DF€OW1DUF|CF

Page 2

All-stage push-pull circuitry. DC servo direct coupled throng]
Head amp with selectable input impendance and gain for opti

In 1977 we introduced the Accuphase
0-220, a preamplifier designed exclusively for
disc sources, The Accuphase C-220 was wide-
ly acclaimed by disc fans everywhere for its
superb performance. However because of the
increasing difficulty of procuring principal de-
vices for its assembly, we were forced to
suspend production in 1980.

The new Accuphase 0-222 preamplifier is
also designed primarily for disc reproduction.
However, It has, with its LINE INPUT and TAPE
PLAY/REC terminals, the added yersatility of
accommodating other sources as well. A Loud-
ness Compensator and a Filter Network are
also provided to eliminate infransonic noise.

The 0222 is a high quality Direct Coupled
(DC) preamplifier. Its basic circuitry utilizes an
all-stage push-pull arrangement with cascode
amplification. The use of coupling capacitors
has been completely obviated in the 0-222
from the MC (Moving Coil cartridge) input stage
to the outpUt stage. An effective DC Servo
Control system makes this possible by covering
all of the unit amplifiers.

The 0-222 has a greatly strengthened multi-
ple power supply system that provides each
unit amplifier with its own voltage regulated
power supply. This ensures the ample supply of
low impedance energy all the way into the ultra
high frequency range, and minimizes interfer-
ence between unit amplifiers.

The preservation of sound purity and
achievement of the highest quality sound repro-
duction were the main objectives in creating the
0-222 preamplifier. These considerations gov-
erned not only the choice of sophisticated
circuitry. but also were our incentive for de-
veloping special devices to preserve sound
purity, The design of the circuit board patterns
creates the shortest signal path layouts for
devices and circuit components and in this way
contributes to the fulfillment of the above
objectives,

The 0-222 is equipped with an Input Load
Impedance Selector Switch and a Head Amp
Gain Switch that accommodate and improve
matching conditions with MC cartridges having
differing impedances and/or wide variations of
output voltage levels.

The quality of this preamplifier's Line Input
has been raised to the highest degree pOSSIbIe,
making it a truly new era" preamplifier. It is also
ideal for preamplitying CD (Compact Disc)
program sources.

The Front Panel presents a neat. easy-to
use layout which includes only the Volume,
Input Selector and Attenuator Function Cone
trols. Less frequently used function controls are
all placed in the lower sub-panel.

The 0222 Preamplifier, when used with one
of the following Accuphase power amplifiers:
the P266 (130 W/ch); the P»300X (150 W/ch);
or the P400 (200 W/ch). makes an ideal sound
reproduction combination.

PUSH-PULL CIRCUITRY
THROUGHOUT WITH DIFFEREN-
TIAL AMPLIFIER INPUT, CASCODE
PRE-DRIVE AND DARLINGTON
PAIR OUTPUT STAGES

An amplifiers basic characteristics are
largely determined by its circuit configuration.
In this sense, its circuit makeup is the most
important factor.

Figure 1 shows the circuit diagram of the
C-222's equalizer and high-level amplifier sec-
tions in progressive stages. each of which
features push-pull circuitry throughout. At the
input stage is a differential amplifier with FET
buffer. The cascode PrevDrive stage comprises
transistors 09-012 and the Darlington Pair
Output transistors 013-016,

High frequency range amplification is dele~
gated mainly to the two Cascode Pre-Drive
Amp sections made up of two transistors each
(09/011 and 010/012). This cascode stage
possesses superior high frequency character-
istics and ensures stable operation with very
low distortion.

The Darlington output also is made up of
two pairs of transistors: 013/015 and 014/016.

Low distortion and stable amplification are
assured because the input impedance of this
stage can be multiplied by the tin: (Static
Forward Current Transfer Ratio) of 013 and
014. These circuit considerations. reinforced
by a push»pul| makeup throughout. have en-
abled us to achieve the highest signal purity
and sound quality with superior basic am-
plification characteristics before NFB (Negative
Feedback) application.

HEAD AMPLIFIER WITH WIDE
DYNAMIC RANGE AND HIGH
SlGNAL-TO-NOISE RATIO

An exclusive amplifier for MC cartridges
with flat characteristics is placed before the
equalizer amplifier to solve fundamentally the
problems caused by the low level sign/2
involved. Figure 2 shows the head amplifie
circuit.

The output of MC cartridges is fed directly to
the input circuit without passing through the
FET buffer. Because the head amplifier handles
very low level signals, noise prevention re-

INPUT

INPUT 0

E g g Y a+B
09
3! Or:
03 05
On 015
Q4 06 --oourr=ur
Oi _ _ F s [C l-
: Ora Ora
014
I :r
2 Or
Om
l i o
- B U
___ NFB _
NETWORK
Fig. 1 circuit Diagram of Equallzier Amp and High-level Amp
g % +5
07 03
ll
OUTPUT
Ora
02
05 010
i E ~13

Flg. 2 Circuit Diagram of Head Amp

Page 4

high frequency signal quality. To prevent this.
the 0222 employs logic circutt controlled
relays strategically located between the input
terminals and the circuit boards to create the
straightest and shortest signal input leads
possible

In such a system. the quality of the relay is
crucial. The C-222 employs reliable crossbar-
twtn type relays specially developed for audio
use

These relays. with their contact points of
thinly gold-plated silver palladium alloy. assure
long life. and sure contact action. Moreover.
these relays are sealed in casings to prevent
corrosion.

HEAD AMPS IMPEDANCE AND
GAIN SELECTORS ENSURE
BEST INPUT MATCHING WITH
MC CARTRIDGES

The 0222 was specially designed to obtain
ideal reproduction from MC cartridges that
have wide variations of impedances and output
levels. For example. the output impedances of
MC cartridges vary from 2 ohms to almost 50
ohms a difference of some 20 to 30 times
Outut voltage levels. too. can vary from 001 mV
to 0.5 mV. a difference of 50 times (34 dB).
Although matching MC cartridges to the head
amplifier is not as critical as transformer cou»
pling, for best performance, low output impe-
dance cartridges should be coupled to low
input impedances.

To accommodate the wide variety of MC
cartridges and preserve fine control of sound
quality. the 0-222 provides the following choice
of input impedances: 10 ohms. 30 ohms or 100
ohms.

This allows you to couple MC cartridges in
the 3-ohm impedance range to a load of 10
ohms or 30 ohms. and cartridges with greater
than 10-ohm impedance to a load of either 30
ohms or 100 ohms for closer matching

Also to accommodate MC cartridges with
very low output levels. a Gain Selector switch in
the 0-222 raises the gain to 32 dB rather than
the normally operated head amp gain of 26 dB.

LOAD CAPACITANCE SELECTOR
PERMITS ADJUSTMENTS OF MM
CARTRIDGE SOUND
CHARACTERISTICS

The factors. other than the normal 47-k ohm
impedance of the amplifier input. that deter-
mine the load of MM (Moving-Magnet) car-
tridges are the stray capacitances created by
the tone arm. the shielded lead-in cords and
amp input connectors. Generally. it can be said
that the lower the stray capacitance, the flatter
the response characteristics of the amplifier.
However. use of higher capacitance is often
recommended by some manufacturers of car-
tridges To cope with such conditions. a Load
Capacitance Selector is provided,

This permits additional capacitance selec-
tion of 100 pF. 200 pF and 400 pF and allows
the user to choose the response characteristics
to suit his personal preference.

Power source transformer

0 Top View

COMPLETE TAPE RECORDING
FUNCTIONS
Although priority was given to disc pream-
plrfication. the recording and reproduction of
tapes were not overlooked, The (3-222 provides
connections to two tape recorders for record-
ing. playback and monitoring.

-20 dB ATI'ENUATOR
PROVIDED
An attenuation control is convenient when

beginning record play. searching for tape
positions. or temporarily muting the volume
level when answering the phone. A ~20 dB
Attenuator is provided for this purpose and is
conveniently located next to the VOLUME
control.

EFFECTIVE FILTER
(17/Hzl-12dBloct)
ELIMINATES HARMFUL
INFRASONIC NOISE
An effective -12/dB/oct Filter is provided to
eliminate inlrasonic noise without affecting the
audio frequency range. This is especially effecr
tive to eliminate the effects of harmful. unnecese
sary vibrations in the 2 Hz range such as those
created by stylus vibrational contact with disc
grooves.

Mocupltase C222

STEREO PREAMPLIFIER

Head amp

Equalizer amp

Logic controller

High-level amp

LOUDNESS COMPENSATOR
ENSURES ACOUSTIC
BALANCE AT LOW LISTENING
LEVELS

The 0-222 does not have a tone control.
However. it features automatic loudness com-
pensation instead. which is determined by the
setting of its volume control .

At low listening levels. this feature boosts©
the volume of lower frequency range sounds to
compensate for the inability of human hearing
to perceive the true volume of such sounds.
This helps maintain the audible sound balance
when listening at low volume levels,

The 0-222 offers a choice of two loudness
compensation curves by switch selection.

CONVENIENT HEADPHONE
JACK PROVIDED
A convenient headphone jack is provided
for monitoring or late-hour listening, This jack
can be used for a wide variety of headphones
ranging in impedance from 4 to 100 ohms.

Page 6

. PERFORMANCE GUARAN I
All Accuphase product speci ations are guaranteed as
stated.

0 FREQUENCY RESPONSE:
I TUNER/LINE/
TAPE PLAY INPUT: 1 Hz ID 500,000 HZ: +0. -3.0 dB
20 Hz to ZOIOOO Hz: +0, 0.2 dB

DISC INPUT: 20 Hz to 20.000 Hz: 20.2 dB

0 TOTAL HARMONIC DISTOFITION (IHF stan-
dard):
Will not exceed 0,005% at rated output level, 20 Hz
to 20,000 Hz

. INPUT SENSITIVITY AND IMPEDANCE:

W
'"WT'mm am war-mm (ohm
0mm ((1sz
DISC (SIG AW: OFF/MM) 2.0 KW 05 er 47K
DISC (thump: wean) m mv nmsmv lamlw
DISC (Hm Amp: +32 as) one mv umzsmv Ion mo
runemmyws PLAY IZSmV 315 mV m

. OUTPUT LEVEL AND IMPEDANCE:
OUTPUTS: 2.0 V. 1.0 ohm
TAPE R50 126 mV. 200 ohms (Input: DISC)

GUARANTY SPECIFICAflONS

I A-WEIGNTED SGML-TMSE RATIO:

nun-mm mum new
olscmnwcFFm) mas seas
ulscrtwnnvc new 12¢: mos
morn-mam Kane) sane man
TUNMAPEPLAY am new

o nuluuu 0UTPUTLEVE1.(It umsas ammo-1,20 Hz
to mono in):

TAPE REC: 19.0V (Input: DISC)

. HEADPHONE JACK:
For listening with low impedance (4 to 100 ohms) dynamic
stereo headphones

. MAXIMUM INPUT FOR DISC INPUT (I! 0.005% amnion.

1km):

HEADAMPOFF: 300mV
HEADAMP+2sotaz 15mV
HEADAMF +32ua: 7.5mV

O MINI LOAD PEARCE:
OUTPUTS: 1 kohms
TAPE REC: 10 kohms

O VOLTAGE AMPLIFICATION IN DECIBELS:
TUNER/LINE/TAPE PLAY Input to OUTPUTS: 24 dB
TUNER/LINE/TAPE PLAY Input to TAPE REC Output:

0 dB

DISC (Head Amp: OFF/MM) Input to OUTPUTS: 60 dB
DISC (Head Amp: OFF/MM) Input to TAPE REC Output:
36 dB

HEAD AMP gain: Selectable (or +26 dB and +32 dB

0 LOUDNESS COMPENSAYOH (volume mnultloll I! -30
a):
I: +3dBat100Hz
2: +8 dB at 100 Hz. +6 dB at 20 kHz

. SUBSONIC FILTER: 17 HZ cutofli -12dB/oct.

0 ATTENUATOH: -20dB

O SEMICONDUCTOR COMPLEMENT:
109 Tr's. 9 FETs. 13 I03 and 94 Di's

0 POWER REQUIREMENT:
Voltage selection by reerlng Ior 100V. 1 17V. 220V and
240V. 50/60 Hz operation
PowerConsumptim: 50 Watts

0 DIMENSIONS:
445 mm (17-1/2 Inches) width
128 mm (5-1/16 inches) max. height
373 mm (14-1 1/15 inches) depth

0 WEIGHT: 9.7%(2131bs) net, 14.1 kg (31.01bs) In

shipping canon O

o-zn tut. rum
m. .rm...).umn.m-«x
w. an."
mum .1.

The above data shows the spectrum characteristics oi
transient intermodulation distortion tor the 0-222 when
two mixed input signals. a 3.18 kHz square wave and
a 15 kHz sine wave are used. Since harmonics of
square waves appear almost infinitely at odd-number
multiples. for example in this case at 9.54 kHz (3rd
harmonic) and 15.9 kHz (5th harmonic). they can
create, together with the 15 kHz input sine wave,
intermodulated spectrums at frequencies where input
signals are absent For example. it the third harmonic
oi the 3.18 kHz square wave (9.54 kHz) and the 15
kHz input signal intermodulate. a spectrum can
appear at the ditlerence oi their lrequencies. or 5146
kHz (15-9.54=5.46 kHz) However, the above data
shows no spectrum above -93 dB at that frequency.
This confirms that TIM distortion is less than 000227;»

'I
nos '

' IIQIIU
I

ACCUPi-iAsé LABORATORY INC

KSSSY

851-0042-00 (G4) PRINTED IN JAPAN