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1,000,000yen (November, 1977 release)
Stereo DC power amplifier which realized a low
distortion and high power by A+ class operation.
class amplification scheme which technics developed has adopted.
Class-A amplifier is using the linear-line fraction of an amplification element
in the full cycle of a signal, neither switching distortion nor crossover
distortion exists theoretically, but there is a tone-quality merit. However, it
is necessary to always send the electric current of the one-half of the peak
current also at the time of a non-signal, and has the fault that it is
inefficient as an amplifying circuit.
In A+ class operation
adopted as SE-A1, the floating of the grounding potential of the Class-A
amplifier which always needs an electric current is carried out, and the high
voltage is supplied from the power-source amplifier formed separately if needed
synchronizing with the swing of an audio signal. it is a twist in this -- the
forced-air-cooling fan is eliminated, securing an output.
toroidal transformer with little direct current resistance is carried in the
power-source part every one right and left each. Moreover, A+ class
amplifier is equipped with the electrolytic capacitor 22,000 micro Fx4
100,000micro-Fx4 and for power-source amplifier, and it has 2 monophonic
composition of four power sources and a total of eight power sources per
DC amplifier stream composition which banished the coupling
capacitor of an input and an output and the capacitor in a NFB loop is adopted, and the outstanding waveform-transmission property is realized.
Moreover, active thermal servo amplifier is adopted as the measure against DC drift, and
since another path by which the suppression of DC drift was separated from the
signal system is performing by the thermal feedback to the first rank, DC gain
of a signal system is always kept constant.
In consideration of the case
where DC component goes into a speaker, the protection network which a relay
works and separates a circuitry from a speaker termination is carried.
Furthermore, when a speaker termination short-circuits by misuse etc., a current
limiter works and a circuitry is protected. Moreover, a current limiter works
also to the temperature rise of the transistor due to the fall of a load
impedance, and a transistor is protected.
The peek meter of the
high-speed response correctly directed also by attack-time 50microsec and 20kHz1
wave is carried.
The tick mark serves as a regular-intervals logarithmic
comression window of +10dB--50dB.
The speaker output control switchpoint
(0--20dB) with four independent lines in which level presetting is possible is
4 step speaker impedance change-over switch for meter is
Fade-in / out organization without shocking sound are carried
to the transient occurrence at the time of input ON/OFF, and DC / low cut
By power-source ON-OFF of a preamplifier, power-source ON-OFF
of power amplifier can be operated by remote control.
||Stereo DC power amplifier
|Effective output (both channel drive)
||350W+350W (4 ohms, 20Hz - 20kHz)
350W+350W (8 ohms, 20Hz - 20kHz)
||0.003% (at the time of an Output power 20Hz
Incapable measurement (at the time of an Output power 1kHz)
0.01% (175W, Output-power-3dB o'clock, 100kHz)
||5Hz - 100kHz (8 ohms, both channel drive, 0.01%)
||20Hz-20kHz+0 -0.05 dB
|SN ratio (IHF-A)
||500 microvolts (150 microvolts, IHF-A)
||More than 70v/microsec
||1V - 10V (succession variable) / 47kohm
||A or B or C or D : 4ohms - 16ohms
B+C or A+C: 8ohm-16ohm
||- 50dB - +10dB (regular-intervals tick mark)
|Frequency characteristic (indication
||10Hz-20kHz±1dB (at the time of +10dB - -40dB
10Hz-10kHz±3dB (at the time of a less than -40dB indication)
||Width 450x height 249x depth of 550mm