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| Exclusive M4a |
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| 430,000yen(around the 1981 time) |
Stereo power amplifier
which asked the class-A-amplification circuitry for the high tone quality of the
quality.
Circuitry is an input stage of the differential amplifier, drives the pre-driver
stage of a push pull, and is driving the last stage of eight power transistors
per single-sided channel (four-piece parallel connection).
The
push-pull circuit of the Class-A operation is the circuitry which was
essentially excellent also in the distortion when not applying NFB few in order
to have neither notching distortion nor crossover distortion. Moreover, in order
that there may be no variation of the power source by the size of power, it
excels especially in low-pass stability and transient.
Capacitors, such
as a Mylar, a polystyrene capacitor, and contest electrolysis, a unguided volume
non-magnetic-material resistor, etc. are developing and using the thing of special edition over each of tone-quality component partses.
In order to
suppress a distorted occurrence as much as possible, the
oxygen-free-high-conductivity-copper line is adopted as product-line material.
The 140micro thickness Copper-foil glass epoxy group board is adopted as
a substrate.
Although the conventional glass epoxy group board was sticking and using
a 35micro Copper foil, in order to aim at DCR (direct current resistance)
in a substrate, and a falloff of an inductance, the 140micro Copper foil
used as 4 times over the past is adopted.
In order to secure the
stable performance and robustness, all of an input/output terminal and the
termination of each assembly are raising the conduction characteristic sharply,
such as using gilding.
In order to stabilize a plating and to stick conventionally, nickel plating
had been performed to the ground, but there was a distorted occurrence
to which nickel originates in a hysteresis since ferromagnetic material.
It plated with the newly developed pin jack adopted as M4a on the ground
of non-magnetic material which shows nickel, equivalent, or the stability
beyond it, and the distorted occurrence was prevented and the stable contact
performance has been obtained.
The hi-reliability and
the mass (15A) power cord which performed the double insulation are adopted as a
power cord.
Furthermore, the polar unification is aimed at by classifying the cable
of a power cord by color by white and black, and managing the interconnection
with AC plug.
A connecting cord is suppressing the distorted occurrence in a connecting
cord, such as using for a pin plug the gilding plug which consists of a
non-magnetic-material ground, as much as possible while using an oxygen-free-high-conductivity-copper
line for a material. Moreover, the structure of the connecting cord is
aiming at the reduction of the inductance by adopting a different star-quad
scheme from the conventional coaxial structure which made the cable with
which a signal line counters mutually gather. Furthermore, the perfect
shielding according a signal line to an electrically conducting polymer
material and a braid is performed.
There is little distorted occurrence by
these and quality signal transmission is possible at a low loss.
In
order to correspond to an exothermic of Class-A amplifier, it had the stream
composition that the interior of a chassis formed the duct for cooling, and the
forced-air-cooling scheme is taken using two fans with whom the cabinet lower
was equipped. Furthermore, in order to stop a fan's rotation sound, a low-speed
operation is carried out by a low voltage.
In addition to the outputting
point direct-current potential detector where the protection network combined
the conventional relay and the electronic circuitry, the protection network by
the heat detecting element and thyristor of a posister using is added.
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| Form |
Stereo power amplifier |
| Circuit system |
Two steps of differentials, PP drive, two-step Darlington, quadruple PP
Pure complimentary OCL (Class-A operation)
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| Effective output (20Hz - 20kHz, both channel drive) |
50W+50W (8ohm) |
| THD (20Hz - 20kHz) |
0.01% or less (at the time of an effective
output)
0.01% or less (at the time of 25W output)
0.01% or less (at the
time of 1W output) |
| Cross modulation distortion |
0.01% or less (at the time of an effective
output)
0.01% or less (at the time of 25W output)
0.01% or less (at the
time of 1W output) |
| Output bandwidth (IHF, both channel drive) |
5Hz - 100kHz (THD 0.05%) |
| Frequency characteristic (at the time of 1W
output) |
3Hz-60kHz+0 -1 dB |
| Input sensitivity/impedance |
Input1, 2:1V, 2V/50kohm |
| Output-terminal |
Speaker: 8ohm |
| Dumping factor (20Hz - 20kHz, 8ohm) |
30 or more |
| Subsonic Filter |
8Hz, 6dB / oct |
S/N
(IHF, A network, a short circuit)
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110dB or more |
| The semiconductor used |
Transistor: 59 pieces
IC: Six pieces
Diode,others: 67 pieces |
| Supply voltage |
AC100V, 50Hz/60Hz |
| Power dissipation (maximum electric power
consumption) |
320W (Electrical Appliance and Material
Control Law) |
| Power receptacle |
Power-switch un-interlocking.: One line
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| Dimensions |
Width 468x height 206x depth of 385mm
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| Weight |
27.3kg |
| Adjunct |
A relay code with a pin plug |
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