|398,000yen(January, 1980 release)
Stereo power amplifier which used as the base the
large-sized power amplifier M-4000 put on the market in 1975, made the newest
technology the injection, and raised completeness further.
The Duo beta
circuitry original with LUX is carried for the improvement in a tone quality.
In this circuitry, NFB of a suitable quantity for all the bands was applied, and DC servo circuitry is combined with super-low-pass one. By this, the
character of the tone quality of all the bands was decided, the revise was added
to the super-low-pass one besides an audio frequency band, and the settlement as
an overall has been obtained.
Moreover, in order to cancel the vicious circle of applying NFB in large
quantities in order that gain may become high and may stop this so that
the nakedness property of amplifier is improved, and carrying out a tone-quality
failure, a nakedness property is excellent, and amplifier with little gain
is made, and NFB is reduced sharply. As a result, the TIM distortion by
the difference of how to require NFB in low-pass and a high region is removed.
Furthermore, DC servo circuitry has realized the low-pass
play which cut the super-low-pass noise and became tight, and also enlarges a
super-low-pass dumping factor, and is raising the resolution of a low-pass play.
Moreover, the problem of DC drift was solved and the effect has been acquired
also to the speaker protection.
While adopting four power MOS FET as an
output stage and sending 300mA or more of bias currents, the notchless class A
operation which does not carry out a switching operation is made combining the
high-speed driver circuitry.
In order that gain suitable for a Duo beta
circuitry may realize the low good amplifier of a nakedness property, a thorough
review of circuitry and a material is performed and the nakedness property is
The first rank constitutes the cascode differential amplifier by
FET strong against a transition of ambient temperature or a voltage dual
monolithic type, and the combination of a high resisting pressure low-noise
transistor, and has acquired the outstanding high region property. Moreover, the
predrive stage adds a current mirror load intensity to a cascode
differential-amplifier circuitry, and is aiming at the modification of a
linearity. And the drive stage and an output stage constituted the pure
complimentary SEPP circuit, and have taken out the Oide power by the low
In these results, the naked distortion serves as outstanding
amplifier with which the naked frequency characteristic was extended on a single
figure to one fifth of amplifier conventionally.
In order to carry out
thorough exclusion of the interference between the right-and-left channels of an
input signal, the power transformer of right-and-left full independence is
begun, all the circuitries are formed into a twin monophonic recording, and it
is considered as the structure which unified monophonic amplifier x2.
Moreover, the simplification of the product line is attained, the substrate
was blocked and secular change have adopted little reliable glass epoxy as a
material. Furthermore, careful selection adoption of the connector of
hi-reliability often used for communication equipment etc. is carried out, it
plates with gold also in the termination side by the side of a substrate, and
the robustness of the contact is improved to the terminal area of the substrate.
Two good large-sized toroidal transformers of a regulation were adopted
as the power-source part, and it has combined with the high-speed
constant-voltage regulated power supply of the twin monophonic stream
An output stage constant-voltage-ized even the pre-driver
stage, and has made the powerful power-source part to it while it carries out
the careful selection using of the tone-quality measure type mass capacitor of
15,000 micro Fx2.
Three-fold protection network is carried in M-4000A.
One is a speaker protection network, excessive DC input enters, and if DC
component is detected by the output-terminal, it will work.
the Dainyuu power is added short-circuited +- of a speaker termination, amplifier is protected doubly in the protection network by the overcurrent
detection for preventing a destructive of a transistor, and the protection
network by the fuse fusing detection for power transistors.
metals coat type, the Detent volume of the same type as a high-class Attenuator
The chimney type heat sink made from aluminum die-casting is
The Subsonic Filter is carried, and while giving the
functionality which cuts the super-low-pass noise leading to cross modulation
distortion, it is considered as the measure against DC input.
connector is adopted as an output-terminal, while plating with gold at an input
terminal and improving a robustness.
The grounding terminal is carried.
||Duo beta circuit stereo power amplifier
|Succession effective output (20Hz - 20kHz)
Both channel concurrent / one-side-channel operation
|THD (8 ohms, 20Hz - 20kHz)
||0.008% or less (180W)
|Cross modulation distortion (8 ohms,
||0.008% or less (180W)
||100kHz [ 3Hz - ]-less than 1dB
||10Hz - -100kHz three dB (0.1%)
|SN ratio (IHF-A correction)
||116dB or more
||0.2mV or less
|Crosstalk (Volume maxima)
||- 100dB or less (1kHz)
- 80dB or less
(20Hz - 20kHz)
||100 (at the time of an 8-ohm load intensity)
||The speaker protection network by a speaker
termination DC drift
The amplifier protection network by overcurrent
The amplifier protection network by the fuse fusing detection for
Peek indicator (it is with the switchpoint of on/off of a peek indicator)
Meter sensitivity changeover switch
The input level set of 22 points of 1dB space-characters Detent
(Electrical Appliance and Material Control Law)
||Width 491x height 181x depth of 390mm