|580,000 yen(April, 1992 release)
preamplifiers only for a high level line, such as CD which the thought and the
grade of C-280V were inherited, and it came out, was developed, and was reformed
completely at all the points from the founder C-270.
transmission circuit is adopted as a line amplifier part like C-280V. Balance
transmission is a system which sends simultaneously the positive/negative
symmetrical signal which the phase reversed mutually, and is excellent in the
capability to remove the noise ingredient in the common mode.
With the line amplifier of C-280V, it consists of three differential amplifier fundamentally
at the time of balance transmission, and amp1 becomes an input and amp2 and amp3
become an output. From +-both the inputs of amp1, a signal enters, and is
amplified, and it is inputted into the following amp2 and amp3. 2 sets of these amplifier has a relation of tucking up its sleeves with a cord which feeds back
each output to the other party, and sends out the symmetrical signal of +- by
Moreover, in making imbalanced connection, the
input-and-output side operates normally only by connecting the terminal of
either one side to a grand (ground) line.
In C-270V, the line amplifier
for a disequilibrium output and the line amplifier for a balanced output are
equipped independently, respectively.
With the line amplifier for a
disequilibrium output, the input unit is a sauce follower of the constant
current load dregs cord bootstrap by all FET, and is amplifying it in the
balanced symmetrical type differential push pull emitter earthed circuit with
this high phase signal removal ratio. The output unit consists of symmetrical
type dregs cord push pull + emitter follower circuits.
With the line amplifier for a balanced output, the balanced output circuit is added to the
same exclusive input circuit as disequilibrium output amplifier. this output
circuit is the same as that of C-280V -- reversal amplifier and each reversed
amplifier -- the bridge feedback which applied feedback to a partner's amplifier
constitutes a balance output, and reversal and a reversed output are completely
separated from the ground.
direct-current servo is applied to all of these
unit amplifier, and, as for the capacitor for a direct-current cut, an input and
an output are not inserted.
A power-source part achieves right-and-left
independence also with a transformer and a filter capacitor, and has monophonic
composition completely electrically. Furthermore, the broadband low impedance
power source was carried in all the unit amplifier, and the mutual intervention
between amplifier is prevented.
4 linkage volume controller by CP
(conductive plastic) element is adopted as the volume which has big influence on
CP element currently used as an object for studio is used for
the resistance object, and high temperature pressurization fabrication is
carried out after printing a resistive element. And the surface of the element
was finished in the shape of a specular surface, and low contact resistance and
a low distortion are realized.
The brush in contact with a resistance object
is a gilding many contact type, is made into an external terminal and solid
construction, abolishes a metal-to- metal contact side, and is reducing
distortion by different-species metal contacting.
Moreover, a rotary system
is considering it as the structure which is not a method which a brush rotates
and a resistance object rotates, it decreases sharply, and makes the internal
point of contact unnecessary [ contact grease ], and its durability is also
A 極太 brass shaft 8mm in diameter is supported by an aluminum
cutting bearing, four elements are stored in a high precision aluminum cutting
case, respectively, a perfect shield is given to the case of a tone control
machine, and improvement in sound quality is aimed at to it.
system is continuation good transformation and the tracking error has realized
survey of less than 0.5dB in a position of -60dB.
The logic relay
control circuit is adopted as the change of an incoming signal.
system, the high reliability relay was installed in each local, and since the
timing of a change is controlled by the logic circuit, it prevented leading
about of wiring and has prevented sound quality degradation.
full sealing structure relay containing [ which was developed as an object for
audios for - communication machines ] nitrogen gas is adopted especially as a
relay, and the contact which influences sound quality has realized low contact
resistance and quantity durability with the crossbar twin system of gold and a
silver palladium alloy.
C-270V consists of right-and-left a total of six
units of the line amplifier for a balanced output divided into the line amplifier for a disequilibrium output, and two units. A print circuit board and
the local-area power source which cannot receive interference easily become a
pair, and each unit amplifier is stored by thick aluminum housing.
electric stability or service nature consideration, it is being fixed on the
large-sized Mother printed board, and these are being fixed with the chassis by
the aluminum material of 8mm thickness so that it may not interfere electrically
The exclusive headphone amplifier of a direct
connection system is carried.
The characteristic jack to which rhodium
plating was performed is adopted as an input-and-output jack, and outstanding
durability is realized.
Three step type Attenuator is carried.
Channel balance is made perfect and the right-and-left independent Attenuator
type level control which can control the normal position by arbitrary listening
positions is carried. It is possible to adjust for 0 - -6dB to character
at intervals of 1dB to -14dB a 0.5dB step and henceforth.
resistive element has adopted the low distortion type of specular surface
The phase switch which reverses the phase of the whole
equipment is carried.
Since a change system only replaces +- of the balance amplifier input unit and does not have an addition circuit like a phase
inversion machine, there is no sound quality degradation.
Compensation switch which rectifies the shortage of massive at the time of small
volume is carried, and the position of a volume controller rectifies the
Two tape recorders are connected, and the
monitor switch is carried so that recording, playback, and a monitor can be
Balance / imbalanced conversion circuit for exclusive use are
equipped so that tape relations can be used in the time of balance as well as
the time of unbalance. Moreover, the copy of tape recorders is also possible.
Furthermore, a tuner output is outputted to a tape recorder output terminal
also in the time of the power source off of C-270V for absence recording.
The board of natural persimmon finishing is attached to both sides.
|balanced input (CD, Line) :
||1.0Hz-300kHz+0 -3.0 dB
|CD, Tuner, Line, Tape Play :
||1.0Hz-300kHz+0 -3.0 dB
||0.005% (with all the input terminals)
(at the time
of an Output power / 0.5V output)
|An Output power/impedance
||Balanced output: 2.0V/50 ohm
output: 2.0V/1 ohm
Tape rec: 252mV/100 ohms
||Conformity impedance: 4ohms - 600ohms
|S/N and input conversion noise
short-circuit IHF-A compensation
|Rated input S/N
||Input conversion noise
a distortion, 20Hz - 20kHz)
|Minimum load impedance
||Balanced output: 600ohms
Tape rec: 10kohm
||Balanced input->Balanced output: 18dB
Balanced input->Unbalanced output: 18dB
Unbalanced input->Balanced output: 18dB
input->Unbalanced output: 18dB
Unbalanced input->rec output: 0dB
2: +8dB (100Hz), +6dB
||- 20dB-30dB, -infinity
|The semiconductor used
||Transistor: 74 pieces
FET: 36 pieces
IC: 25 pieces
Diode: 97 pieces
|Power supply voltage
||Width 468x height 149x depth of 403mm