Audio Database

The

SANSUI AU-alpha 307
45,000yen(around the 1989 time)

Description
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The Integrated Amplifier which gained high dynamic power by strengthening of the power-source part.

By the power-source scheme which adopted the complementary circuit, the variation in a center-tap and the unbalanced current of the load current are flowing, and it had had an ill effect on the tone quality.
In order to improve this, the grand stabilized circuit is adopted between a center-tap and a grounding, the spike noise is eliminated rationally, and, thereby, SN on Hearing impression is improved not only at the time of the Oide power but at the time of the Koide power.

A power amplifier part adopts a high speed power transistor as the final stage of the power amplification stage, and constitutes it from a three-step Darlington complimentary push pull.
Moreover, in the driver stage, it has a differential amplification with a first rank transistor, and discrete composition which adopted the 2nd step of complimentary push-pull circuit.

MC phone equalizer with a High/Low switching is carried, and the Output load impedance of MC cartridge is supported.

The REC selector with an off-position is carried.

Power-source

Rating of a mode
Form Integrated amplifier
<Power amplifier part>
Effective output (10Hz - 20kHz, both channel operation) 75W+75W (6ohm)
65W+65W (8ohm)
THD (at the time of an effective output) 0.05% or less (8ohm)
Frequency characteristic (1W) 1Hz-200kHz+0 -3 dB
SN ratio (A network) 105dB or more
<Preamplifier part>
Input sensitivity/impedance (1kHz) Phono man month: 3.5mV / 47kohm
Phono MC: 420 microvolts (Low:22ohm, High: 100ohm)
compact disk, Tuner, Line, Tape Play:200mV /, 47kohm
Phono maximum permissible input MM(THD 0.1%):130mV
Frequency characteristic Phono man month: 20Hz-20kHz}0.5dB
compact disk, Tuner, Line, and Tape Play:1Hz-200kHz+0 -3 dB
SN ratio (A network) Phono man month: 80dB or more
Phono MC: 65dB or more
compact disk, Tuner, Line, Tape Play: 105dB or more
Tone control The Bass maximum variation: }8dB (50Hz)
The Treble maximum variation: }8dB (10kHz)
Subsonic Filter 16Hz (-3dB), 6dB / oct
Loudness + 10dB (50Hz), +4dB (10kHz)
<Synthesis>
Power dissipation 170W
Dimensions Width 430x height 136x depth of 311mm
Weight 9.0kg