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| NEC A-10TypeIII |
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| 118,000yen(March 21, 1986 release) |
It is the still firmer Integrated Amplifier at the
base with which the enhancement was performed to the reserve power-source scheme
etc. while rigid-structure-izing about A-10TypeII.
The original
mechanical ground construction is adopted as a structure.
This is the thing
cancels an oscillation of each component partses in which the oscillation modes
differ in an overall structure, and it was made to suit by a computer simulation
on it as the material and the structure of pressing down an oscillation of each
component partses thoroughly,This simplified oscillation is dropped on a huge
foot, and it ties to a terrestrial mass and holds down.
In A-10TypeIII,
strengthening and refinement are carried out further, the opportunity reference
point of the set itself was made into the structure which responds to all the
mechanical vibration on foot as a foot of a main unit, and a sintered alloy foot
50mm in diameter and 22mm in height is adopted as the insulator arranged at four
places of a sole plate.
Moreover, in order to connect a structure division
article and a power transformer to a foot certainly, the 3.2mm griddle in
thickness is adopted as a sole plate.
Furthermore, the cloth beam which
solid-construction-izes sub- metal fittings on either side, a rear panel, and a
heat sink is adopted, a base and a cloth beam are connected with four beams, and
the core of a power transformer is certainly fixed to the beam.
Moreover, in
order to prevent the resonance of a fin, the chimney type heat sink is adopted.
According to this rigid structure, the muddiness and cloudiness of sound
based on the material of a ground plane, a structure, and the relative
relationship of amplifier are eliminated by grounding a main unit and a
terrestrial mass firmly.
In addition, the insulator can select the one two
back + front and the two one back + front besides the usual 4-piece shorted to
ground.
In order to approach the ideal image of the amplifier "one wire
with amplification degree", Simple & Straight thought is adopted and the
pure quality is realized by 1 contact hardwired connection which jumps all, such
as an attached circuitry, if needed.
In order to taste the dynamic range and
high quality which were excellent in the digital sources, such as compact disk,
the direct input to a power amplifier part is carried.
While newly
reexamining the improvement in a quality of a Phono system in A-10TypeIII and
measuring DC servo-ization of EQ amplifier,Phono Direct Position which puts
Phono amplifier and power amplifier in order as a 1 contact hardwired connection
by using of a high reliance relay is carried.
It was not concerned with
the source under play, but the REC selector scheme which can record the favorite
source is adopted.
Moreover, in order to be able to connect a very-thick
speaker code certainly, the large-sized vice type screw terminal is adopted.
Moreover, it becomes possible to use the rear panel which supports a speaker
terminal part by this as non-magnetic-material material, and is released from
electric disturbance by banishing the magnetic substance from the loop of the
speaker output current.
The line filter which protects mixing of a noise and with a jump is carried in the AC outlet.
This AC outlet operates by an
unswitched and also has a polar window.
As for the signal currently
recorded on the CD software marketed, straight polarity and reversed polarity
are intermingled.
In A-10TypeIII, in order to carry out a polar mandatory in
system total, the polarity-reversal Pre Out termination is carried for the
software of reversed polarity.
By connecting the reversed polarity Pre Out
and Main In by attached U character pin, a polarity can be reversed by the
separation position of Operation SW, and total polar doubling becomes possible
by this.
The huge reserve power-source scheme is adopted as a
power-source part.
In order to maintain the Oide power also at the time of
an electric discharge of a capacitor, another power source with which time for
the charging current of a capacitor input type rectifier circuit not to flow is
compensated is prepared, the valley of the ripple of a main power source is
filled up with delaying 90 degrees of phases of the output, and it is considered
as the power source like a battery in equivalent.
Furthermore by
A-10TypeIII, the current capacity of a power transformer, the capacity of the
smoothing capacitor, etc. are reinforced about 20% conventionally, and source
impedance is also falling much more and it has become the more excellent power
source.
While adopting a push pull type amplifying circuit as all the amplification stages, 2SA-1227 of a super linearity and 2SC-2987 which employed
the semiconductor technology of NEC efficiently are used for the last
amplification stage with the parallel push pull stream composition.
It has
avoided without spoiling stability by carrying out the parallel using of the
output transistor for a substantial reduction by half of the emitter resistor
which goes into an output current circuitry in series.
Moreover, the output
circuit which does not need the protection by the 2-ohm load intensity or an ASO
limiter is designed, and the limiter with which a 2-ohm load intensity also
spoils the linearity of the output current does not operate.
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| Form |
High-quality integrated amplifier
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| <Power amplifier part>
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| Circuit system |
Whole page direct DC servo circuitry
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Effective output (both channel drive)
A
sinusoidal input, 20Hz - 20kHz |
120W+120W (4ohm)
60W+60W (8ohm) |
| THD (at the time of an effective output)
|
0.004% or less |
Cross modulation distortion
(at the time of an effective output) |
0.004% or less |
| Frequency characteristic |
5Hz - 300kHz |
| Input sensitivity/impedance |
1.23V/20kohm |
| <Preamplifier part>
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| Circuit system |
High Gm FET direct input DC servo EQ
amplifier circuitry |
| Input sensitivity/impedance |
Phono man month: 2.5mV / 47kohm
compact
disk, Tuner, AUX, Tape1, 2:150mV / 20kohm |
| An Output voltage/impedance |
Rec output: 150mV
Preamplifier output:
1.23V/600 ohm |
| SN ratio |
Phono:90dB(-142dBV)
compact disk, Tuner,
AUX, Tape1, 2:110dB (-126dBV) |
| RIAA deflection |
Less than ±0.2dB |
| Phono maximum permissible input |
150mV |
| Subsonic Filter |
15Hz: -3dB, 6dB / oct
It is a
partitioned to a phone equalizer.
(It is a non filter at the time of Phono
Direct) |
| Input/output phase |
Inphase
However, only pre outs are those
of straight polarity and reversed polarity with both the output.
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| <Synthesis>
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| Circuit system |
Shunt-regulator scheme + reserve power
source |
| Power consumption |
230W |
| Dimensions |
The width 430x height 165x depth of 485mm
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| Weight |
25kg |
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