|125,000yen(October 21, 1987 release)
The Integrated Amplifier which developed and
improved A-10TypeIII further.
Simple&Straight thought is put into
practice and, in addition to compact-disk direct input and Phono Direct Position
which were carried by TypeIII, the main-amplifier part is made direct in TypeIV.
In order to avoid the influence of relay contact of the protection network
which exists just before a speaker termination as much as possible, the speaker
direct termination is adopted and the quality is improved much more by
direct-drive achievement of a speaker.
Furthermore, the OCC shielded cable
of the NEC original is adopted as the wiring in amplifier, and a tone and a
feeling of energy with a bright transparent atmosphere and gloss are reproduced
Moreover, the constant current drive scheme with little influence of
a contact is adopted at the same time it adopts a more nearly high-definition
thing also about a volume.
Reserve power-source dBASE III which improved
the original reserve power source of NEC is carried.
A-10TypeIII, the capacity of a smoothing capacitor is reinforced 16% or
more,Conventional power-source 20,000micro-Fx4, reserve power-source
3,300micro-Fx4, and the huge capacity of a total of 93,200 micro F are
carried,The supply capacity of the charging current of conventional へ improved
from the reserve, and the very smooth power-source wave has been obtained
according to the recovery capacity after the Oide power to have excelled.
Moreover, the propagation by the side of [ the load variation generated in
the sub- side of a transformer ] primary and noise mixing from the primary
transformer side to the sub- side are improved.
Besides it, the very-thick
OFC (oxygen free high conductivity copper) code is used for a power
cord,Furthermore, the thorough refinement to the pureness of a power-source
part, such as adopting the fuse with a lead which loses two contacts which
intervene as a fuse holder, and supplies a power source to the primary
transformer side direct, is carried out.
The mechanical grand
construction is adopted as a rigid structure design.
About the component
partses of each, the material and the structure of suppressing an oscillation
thoroughly were selected carefully, a construction where the natural oscillation
of each part article cancels mutually and which suits by a computer simulation
on it was given, and the simple oscillation finally controlled is dropped into
the huge foot.
In TypeIV, the tuning which makes a sintered alloy foot
high-density is performed with a quality up of a signal system, and
strengthening of a power supply system.
Furthermore, the power transformer
was enclosed with the copper plating case, and while an oscillation peculiar to
a power transformer is held down, the ill effect by leakage magnetic flux is
also prevented by considering it as non-magnetic material.
rectifier diode is also enclosed in a transformer case and holds down the
A selection of the 4/3-piece shorted to ground for
choosing the setting environment and the delicate tone-quality difference of
amplifier and point shorted-to-ground / interview place can be performed like
The push pull type amplifying circuit is adopted as
circuitry in all the amplification stages.
Moreover, by considering the last
amplification stage as a parallel push pull stream composition, the emitter
resistor which goes into an output current circuitry in series is reduced by
half, without spoiling the degree of safe, and the protection by an ASO limiter
also makes a 2-ohm load intensity the unnecessary output circuit.
order to perform a polar mandatory in system total including reversed-polarity
software or a reverse motion speaker, the polarity-reversal Pre Out termination
By connecting the reversed polarity Pre Out and Main In by U
character pin, a polarity is reversed by the separate position of an operation
switchpoint, and total polar doubling is possible.
recording an FM broadcast is possible, carrying the REC selector scheme and
hearing compact disk.
In order to prevent the influence of the tone
quality by leakage magnetic flux etc. as much as possible, the front chassis is
attaining non-magnetic-material-ization by copper plating. Furthermore, the
non-magnetic-material material was adopted also as the rear panel, and various
electric disturbance is eliminated by banishing the magnetic substance from the
loop of the speaker output current.
Moreover, the large-sized vice type also
corresponding to a very-thick speaker cable is adopted as a speaker terminal.
||High-quality integrated amplifier
|<Power amplifier part>
||Whole page direct DC servo circuitry
|Effective output (both channel drive)
sinusoidal input, 20Hz - 20kHz
|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
||5Hz - 300kHz
||High Gm FET direct input DC servo EQ
||Phono man month: 2.5mV / 47kohm
disk, Tuner, AUX, Tape1, 2:150mV / 20kohm
|An Output voltage/impedance
||Rec output: 150mV
compact disk, Tuner,
AUX, Tape1, 2:110dB (-126dBV)
||Less than ±0.2dB
|Phono maximum permissible input
||15Hz: -3dB, 6dB / oct
It is a
partitioned to a phone equalizer.
(It is a non filter at the time of Phono
However, only pre outs are those
of straight polarity and reversed polarity with both the output.
||Shunt-regulator scheme + reserve power
||The width 430x height 165x depth of 485mm