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| Accuphase C-220 |
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| 220,000 yen(June, 1977 release) |
Control amplifier only for a disc developed as a preamplifier only for a record.
record playback -- since a special-purpose machine, neither the aux
terminal nor the tape input terminal is carried. Instead, if the power switch of
C-220 is turned OFF, the terminal direct connected to power amplifier is
prepared. It is connecting with the control amplifier which has already
possessed the tuner and the tape recorder using this, and connecting the amplifier output to EXT.Preamp Input of C-220,The output of the already
possessed control amplifier can connect with power amplifier automatically.
Moreover, when rectifying a frequency response by tone control, it is
possible to use it as equalizer amplifier by connecting with the aux input of
the control amplifier which takes out a signal from Fixed Output of C-220, and
has already been possessed.
The head amplifier for MC cartridges is
built in and, in 26dB and from an equalizer to an output, head amplifier is
giving a gain of 60dB.
Moreover, head amplifier was changed by relay
control, by electronic, a muting relay and time lag of the output were given and
the shocking noise is canceled so that proper use of MC and MM can be performed
with one arm.
Contact resistance selects carefully and uses for the relay
little relay which was excellent in durability over a long period of time.
Circuit composition is using what improved further based on P-300 and
the whole page symmetry push pull circuit developed by C-200.
the base
before this circuit applies NFB -- since the characteristic is excellent, the
low distortion is expectable that much as a result. Furthermore, this circuit is
strong also to power-supply-voltage change, and stable operation is possible for
it.
Each unit amplifier including head amplifier is considered as
direct-current amplifier composition which removed the capacitor of NF loop by
the Class-A drive.
The input unit of head amplifier constitutes the symmetry push pull differential
amplification using four RET (ring emitter transistor) developed as an
object for high frequency electric power magnification. Furthermore, it
has Class-A direct-current amplifier composition which took out the output
by pure complimentary.
RET has structure which
carried out 100-piece parallel composition of the transistor unit for small
signals through ballast resistance of the emitter by a diffusion layer. Electric
power magnification is possible, maintaining the high frequency characteristic
with which the transistor for small signals is equipped by this. This RET was
adopted as the entrance of head amplifier with the smallest signal level, and
reduction of a large noise level is realized. Furthermore, by sending large
current through a magnification element, a circuit is formed into low impedance,
the impedance of the NFB input side of differential amplifier is lowered, and
the noise which a circuit generates is reduced sharply.
The characteristic
whose input conversion noise of a head amplifier part is actual
measurement-154dBV (0.1mV of rated inputs, S/N74dB) and which was excellent is
realized.
The input unit of the equalizer amplifier part is taken as the
input direct connection circuit in the differential amplification circuit
combining the FET buffer.
Moreover, pure complimentary connection of the RET
which excelled [ output ] in the high frequency characteristic is made, an
Output load impedance is lowered by large current drive, and low
impedance-ization of NF loop is enabled.
Thereby, the input conversion noise
of equalizer amplifier has realized -140dBV (2mV of rated inputs, S/N86dB) with
the actual measurement.
The power-source part is attaining stabilization
with direct-current servo amplifier, and makes impedance of each frequency as
low as possible from direct current to the super-high region.
The canon connector output is also carried in the output simultaneously
with the usual RCA pin jack.
A design has two kinds, 19-inch rack-mounted type A type and B
type of a side plate, as well as the multichannel divider F-5.
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| Form |
The preamplifier only for a disc
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| Frequency response |
20Hz-20kHz±0.2dB |
| THD (20Hz - 20kHz, Output power)
|
0.01% |
| A rated input / impedance |
DISC1, 2 (Head amp off):2.0mV/100 ohm,
30kohm, 47kohm, 100kohm
DISC1, 2 (Head amp on):0.1mV/100 ohms
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| An Output power/impedance |
Main output: 2.0V/50 ohm (Volume maximum,
the rated input)
Fixed output: 150mV/200 ohms |
| Minimum load impedance |
Main output: 5.0kohm
Fixed output:
10.0kohm |
S/N
(at the time of input short-circuit, an IHF-A curve, and a rated input) |
Head amp off:85dB
Head amp on:72dB
|
Input conversion noise
(Input
short-circuit, IHF-A curve) |
Head amp off:-139dBV
Head amp on:-152dBV
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| the maximum input (1kHz, 0.01% of
distortion) |
Head amp off:400mVrms
Head amp
on:20mVrms |
| The minimum input level |
10Vrms (20Hz - 20kHz, 0.01% of distortion)
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| Gain (DISC input->Main output)
|
Head amp off:60dB
Head amp on:86dB
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| Volume control linkage error |
Less than 1dB |
| balance adjustment (right and left)
|
0, -0.5, -1.0, -1.5, -2.0, -3.0, -4.0, -5.0,
-6.0, -7.0dB, -infinity |
| The semiconductor used |
Transistor: 109 pieces
FET: 16 pieces
Diode: 34 pieces |
| Power supply voltage |
AC100V/117V/220V/240V, 50Hz/60Hz
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| Power consumption |
65W |
| Dimensions |
A type: Width 482x height 82x depth of 345mm
B type: Width 445x height 82x depth of 349mm |
| Weight |
10.7kg |
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