|700,000 yen(February, 1987 release)
The stereo preamplifier to which improvement, such as carrying the full-scale
balanced type line amplifier by 2 amplifier composition in C-280, and carrying
ten input terminals in it, was added.
In order to realize more balance
transmission which corresponded by the transformer etc. conventionally in high
quality, the balance transmission line amplifier by 2 amplifier composition
which forms an amplifier in the hot and cold side, respectively is carried.
The same complimentary differential push-pull amplification circuit is
completely used for each amplifier.
Moreover, it is controlled in four precise volumes (LR channel linkage) which was divided into cold one also about volume as it is completely hot and which stood in a row.
In addition to all the magnification stage Class-A push
pulls, a cascode system is promoted further, FET is used for the load side of
cascode connection amplifier, and it is asking for little reproduction sound of
coloring more by anxious composition which is not, such as base current leak at
the time of bipolar transistor use.
direct-current servo system by IC
was adopted as all the unit amplifier, and a direct current generated in the
output was detected, it returned to the input, and generating of direct-current
drift is prevented.
By direct-current servo system and precise design,
generating of direct-current drift is made for there almost to be nothing, and
all the signal systems from MC input to an output are made direct connection.
Moreover, a base is firmly fixed with a screw, the output element of Class-A
magnification and the element of the constant-voltage power source are being
stuck and fixed to housing to serve also as heat dissipation, and resonance by
guidance and vibration is prevented.
In the power-source part, a power
transformer for exclusive use is made a right-and-left channel, it takes it, and
it has become the mono-construction which became independent electrically,
structurally, and completely.
Furthermore, in order to attain low
impedance-ization over a broadband, they are a total of six multiple power
supply systems which carry a constant-voltage power source for exclusive use for
every unit amplifier.
Since unit amplifier and a constant-voltage
power-source part are stored by thick aluminum housing and wire connection is
carried out by a curtate distance, they have prevented the rise of the
power-source impedance in a high region.
Since a straight signal course
is constituted at the shortest, a relay is installed in the place of all the
required signal courses, and it is changing by a switch controlling these relays
electronically in a logic circuit.
Especially the relay currently used has
adopted the encapsulated type relay containing [ which was developed as the
object for audios, or an object for communication machines ] nitrogen gas, and a
contact is a crossbar twin system of gold and a silver palladium alloy, and has
become low contact resistance and a thing of high durability which has high
Furthermore, in order to improve reliability more, it is used for a
low-level signal course by 4 circuit parallel, and completeness is expected.
The equalizer amplifier part is selecting carefully and using the low noise
element for the input stage of differential amplification especially, although
a basic circuit is almost the same as that of one side of line amplifier.
The element which makes the RIAA reproducing characteristics
which influence sound quality is constituted from a network which combined
resistance and a capacitor, and has adopted especially as this portion the
silvered mica condenser developed as an object for audios.
forms a silver thin film in the refined piece of mica of high purity by the
screen method, and also has special processing and structure of printing a glass
pattern (thin glass layer). By this, corposant starting potential becomes high,
it is stabilized also in the pulse high voltage, and a signal is passed.
Moreover, since it is directly connected to the edge portion of a silver film,
how to take out the lead which affects sound quality does not have degradation.
In the head amplifier part, low impedance-ization of a NFB loop is
attained and resistance noise is decreased at the same time it uses a low noise
element for an input circuit.
Moreover, in order to avoid the influence of
the noise generated from direct-current servo, it has returned to the base of
not only a method but the current generator which returns to the minus side of
differential amplification directly. Thereby, the influence of the noise of a
servo system was lost mostly, and has realized SN near theoretical full limits.
In order to correspond to various MC cartridges and to be able to
control sound quality minutely, MC input impedance is considered so that it may
change to a three-stage (10ohm, 30ohm, and 100ohm).
Moreover, the gain
changeover switch is provided so that a profit of 32dB may be obtained by
everything but a usual head amplifier profit of 26dB for a low output MC
It thinks not deteriorating over a long period of time as
important, and the jack which performed high-class rhodium plating is specially
made to each input jack, and is used for it. Since it has an altitude which is
equal also to 100 million slides by 1-micrometer thickness and excels also in
corrosion resistance, good contact is maintained over a long period of time.
The Attenuator which leaves volume as it is and can lower volume in an
instant is carried.
With a counterclockwise rotation - 3 step rotary system
to which a level falls is adopted as -20dB and -30dB by infinity (silent) and a
Even if channel balance is made perfect and a
listening point shifts, the right-and-left independent type Attenuator type
level control which can control the normal position is carried.
The monitor switch which can perform the recording / playback / monitor of a tape recorder is carried.
The Compensation which improves low-pitched sound is carried. The Subsonic
Filter is carried.
The profound persimmon wood case is adopted as the panel of a gold tone
scratch hair line.
|CD, Tuner, Line, Tape Play :
||1.0Hz-350kHz+0 -3.0 dB
|CD, Line (Balanced Input) :
||1.0Hz-700kHz+0 -3.0 dB
EIA output 0.5V)
|AD(Head Amp off): 4.0mV/0.5mV/47kohm
AD (Head Amp+26dB): 0.2mV/0.025 mV/10ohm, 30ohm, 100ohm
Amp+32dB): 0.1 mv/0.0125mV/10ohm, 30ohm, 100ohm
CD, Line, Tuner, and
|An Output power/impedance
||Output(Balanced): 2.0V/50 ohm (25ohm/25ohm), a XLR type connector
Outpput(Unbalanced): 2.0V/1 ohm, a RCA phono jack
Tape Rec: 126mV/200 ohm (at the time of AD), a RCA phono jack
|S/N and input conversion noise
short-circuit IHF-A compensation
|Rated input S/N
||Input conversion noise
|AD(Head Amp off):
|AD(Head Amp +26dB):
|AD(Head Amp +32dB):
|CD, Line, Tuner, Tape :
|CD, Line (Balanced) :
a distortion, 20Hz - 20kHz)
Tape Rec:19.0V (at the time of AD)
|The maximum inlet pressure
|AD(Head Amp off):300mV
AD(Head Amp +32dB):7.5mV
|Minimum load impedance
||Output (Balanced): 600ohms (300ohm/300ohm)
Tape Rec: 10kohm
||CD, Line(Balanced) ->Balanced Output:
CD, Tuner, Line, Tape Play->Output:18dB
CD, Tuner, Line, Tape
AD(Head Amp Off) ->Output: 54dB
Off) ->Rec Output: 36dB
AD(Head Amp+26dB) ->Output: 80dB
Amp+26dB) ->Rec Output: 62dB
AD(Head Amp+32dB) ->Output: 86dB
AD(Head Amp+32dB) ->Rec Outpu: 68dB
2: +8dB (100Hz), +6dB
||10Hz, -18 dB/oct
||- 20dB-30dB, -infinity
|The semiconductor used
||Transistor: 219 pieces
FET: 58 pieces
IC: 26 pieces
Diode: 174 pieces
||Width 468x height 171x depth of 396mm