Audio Database

The

SANSUI AU-alpha 707XR
170,000yen(1994 release)

Description
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The Integrated Amplifier which carries the newly developed Hyper alpha-X balance circuitry.

In order to remove distortion generated by the asymmetry of the element, the Hyper alpha-X balance circuitry on the basis of the original technology of X balance amplifier is developed and adopted.
In addition to the conventional balance circuitry, this circuitry newly introduced the high CMRR type constant current circuit into the first rank of the power amplifier and preamplifier which determine the dynamic behavior of amplifier, and has realized the with a theoretical value of 140dB modification effect by CMRR. Thereby, the asymmetry of an element suppresses the variation in the electric current by DC offset of a cause, and is stopping the dynamic noise generated in a circuitry.
Moreover, it was made the balance justice to which a transmit and amplification of a music signal can perform a whole page simultaneously, and the ill effect by the reverse electromotive style and exogenous noise of a speaker is eliminated by carrying out the full separation of an amplifying circuit and the grounding circuitry.
Furthermore, amplifier for exclusive use was put on each by the side of + of an output, and -, and the push pull scheme which drives a speaker on these requirements with a total of four amplifier is adopted.

NM-LAPT which is a device only for an audio was carried in the power stage, and the outstanding RF property and electric-current threshold value are acquired.

The whole page is considered as DC amplifier stream composition from the input to the output.
Furthermore, the NEW diamond differential circuit which can take out the output by the side of - without phase inversion is adopted, the responsibility over a momentary signal is improved, and the performance of DC amplifier is improved by suppressing an occurrence of TIM distortion.
Moreover, the tone-quality failure which takes place in the case of the interconnection with the external equipment which makes FET of the first rank cascade connection and differs a circuitry in an impedance in order to high-speed-ize, a wide range and is canceled.

In order to prevent imbalanced-ization of a power source in a power-source part, while supplying the large current which adopted the closed-loop stream composition which made the power-source part become independent of a grounding, had also separated particularlies, such as a power stage and a voltage amplification stage, completely, and was stabilized,The signal is protected from the noise generated at the time of the natural oscillation and charge and discharge of a power-source part.

In order to prevent the oscillation generated from a power supply system or a signal system, the strengthening twin monophonic construction is adopted.
First, the large-sized transformer and the electrolytic capacitor were installed in the central part, and also the power unit which consists of signals systems, such as a power transistor and a radiator, was placed symmetrically, and the optimal weight balance is secured.
Moreover, the isorated mechanical feedback which is an original technology is introduced,Pure-copper material, a Teflon sheet, and a Teflon tapes are utilized for the roots on which an oscillation is transmitted, such as between a master volume, between chassis and a transformer, between chassis and NM-LAPT, and radiators, and the oscillation is effectively suppressed on them.
Furthermore, the extraneous vibration is intercepted by the ellipse insulator of a special structure.

The power amplifier direct input which can input the music signal of the digital source into a direct power amplifier part, and the balance input terminal are carried.

The 6-unit Detent volume is adopted as a volume.

The source power direct, an REC serector, an AC outlet, etc. are carried.

Rear
Internal Ellipse

Rating of a mode
Form Integrated amplifier
<Power amplifier part>
Effective output (10Hz - 20kHz)
Both channel simultaneous operation
160W+160W (6ohm)
130W+130W (8ohm)
THD (at the time of an effective output) 0.003% or less (8ohm)
Cross modulation distortion 0.003% or less (8ohm)
Dumping factor 150 (8ohm)
Frequency characteristic (1W) DC-300kHz+0 -3dB
Input sensitivity/impedance 1V / 5kohm (1kHz)
SN ratio (A network) 120dB or more
Dynamic power 405W (2ohm)
320W (4ohm)
210W (6ohm)
TIM distortion (SAWTOOTH) Below a limit-of-measurement value
Slew rate 200v/microsec
Rise time 0.5microsec
<Preamplifier part>
Input sensitivity/impedance
(1kHz)
Phono man month: 2.5mV / 47kohm
Phono MC: 300 microvolts/100 ohms
compact disk, Tuner, Line, Tape/DAT1, 2:150mV / 20kohm
Phono maximum permissible input MM(THD 0.01%):210mV
MC(THD 0.1%):21mV
the frequency characteristic (1W) Phono man month: 20Hz-20kHz}0.2dB
compact disk, Tuner, Line, Tape/DAT1, and 2:DC-200kHz+0 -3 dB
SN ratio (A network) Phono man month: 88dB or more
Phono MC: 70dB or more
compact disk, TUner, Line, Tape/DAT1, 2:110dB or more
Tone control The Bass maximum variation: }6dB (50Hz)
The Treble maximum variation: }6dB (15kHz)
Subsonic Filter 16Hz (-3dB), 6dB / oct
Loudness +6dB(50Hz)
+4dB(10kHz)
<Synthesis>
Power dissipation 330W
Dimensions Width 466x height 162x depth of 452mm
Weight 23.0kg