Audio Database

The

SANSUI AU-alpha 907XR
278,000yen(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.
Furthermore, newly developed parts which held down leakage flux to the min and enclosed the high-density fill with the shielding case of the quadruplicate structure, such as a large-sized power transformer of 13kg of total weights and an ellipse form electrolytic capacitor, are adopted.

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,The isolation part made from a pure copper is used for the installment base of an electrolytic capacitor between a master volume and a chassis and between a power transistor and a radiator, and the internal loss is intercepting the channels of communication of an oscillation taking advantage of the property of having the vibrational absorption capacity to have excelled greatly.
Furthermore, in order to carry out the isolated rate between an insulator and sole plates and of between a bonnet and chassis etc., the molecular structure makes full use of extremely stable a Teflon tapes and a Teflon sheet, and is suppressing the failure of the tone quality by an oscillation or vibration.

the bonnet which gave the top quality part for a high-quality sound play, and the newly developed pure-copper ellipse insulator and the coating containing copper powder, and a copper plating rear panel -- aluminum Naked shaving appearance is carried out and the volume thumb etc. is attaining vibration proof, low-impedance-izing, and non-magnetic-material-ization to the detail.

In order to suppress a failure of a tone quality to the minimum, simple-ization of the signal transmission circuitry is performed, and the tone control is eliminated.
Moreover, 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, the REC serector, and the AC outlet are carried.

Rear
Internal Power-source
Power NM-LAPT
Volume Using Power Pure-copper

Rating of a mode
Form Integrated amplifier
<Power amplifier part>
Effective output (10Hz - 20kHz)
Both channel simultaneous operation
190W+190W (6ohm)
160W+160W (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 (8ohms)
Frequency characteristic (1W) DC-300kHz+0 -3dB
Input sensitivity/impedance (1kHz) 1V/5kohm
SN ratio (A network) 120dB or more
Dynamic power 580W (2ohm)
390W (4ohm)
310W (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-300kHz+0 -3 dB
SN ratio (A network) Phono man month: 90dB or more
Phono MC: 75dB or more
compact disk, TUner, Line, Tape/DAT1, 2:110dB or more
Subsonic Filter 16Hz (-3dB), 6dB / oct
Loudness +4dB(50Hz)
+3dB(10kHz)
<Synthesis>
Power dissipation 400W
Dimensions Width 466x height 163x depth of 452mm
Weight 33.0kg