Audio Database

The

SANSUI AU-alpha 907i
198,000yen(1987 release)

Description
@
The stereo Integrated Amplifier which adopted the alpha-X balance circuit.

An alpha-X balance circuit is a scheme transmitted and amplified with the exclusive amplifier which became independent to both by the side of + of a signal, and -, and since it has dissociated with the grounding, it is suppressing the noise and the distorted influence from a grounding theoretically.
Moreover, the power part input stage is considered as the differential balance input stream composition which uses low-noise FET, and since inphase component removal ratio:CMRR (Common Mode Rejection Rato) by the side of + of a signal system and - is large, the circuitry itself has canceled an inphase noise and distortion.
Moreover, in order to drive from the bothways by the side of + side - rather than to drive between an amplifier output and a grounding like the conventional amplifier, a power supply system noise did not mix but the occurrence of IHM (Interface Hum Modulation) by the counter-electromotive force from a speaker is prevented.

The original balance power source which was made to become independent of a grounding and was made into the closed loop is used for a power-source part.
+ While an electric current is equal and always prevents the ill effect to the signal by the unbalance of a power source by the side and - side, it is a design strong also against the noise and power supply variation from AC line.
moreover, to the transformer, vibration proof and thermal resistance were strengthened with the high-density fill -- the large-sized transformer is overly carried.
Moreover, the custom-made electrolytic capacitor only for an audio with a quick charge-and-discharge speed and large-current capacity first recovery diode are adopted.

In addition to the master regulator who combines with a power transformer, the twin regulator system which has stationed the local regulator on a phone equalizer substrate and a preamplifier substrate is adopted.
For the regulator of a two-step stream composition, it is strong to a power supply variation or a load variation, and the stable clean powering is made possible.

The power-source part which makes a power transformer an entity was set in the center, and the twin monophonic construction which has arranged the power amplifier part symmetrically with the right and left is adopted.
Furthermore, the De Dis Pau Shal substrate which cuts a detailed oscillation of a substrate is adopted as the substrate of a power part.

The solid & anti flux chassis which the work which eliminates an oscillation and an interference of a noise was made is used for the chassis. While carrying out the full separation shielding of each stage with a separator, five large-sized insulators (certain-factor5 insulator) by which loading distribution was carried out the optimal are used.

A volume has little tone-quality failure, it has adopted the small high precision 6-unit Detent type volume of a right-and-left interlock error as it, it can narrow down to it to near -90dB, and the SN ratio on a package is improved.

The phone equalizer of a discrete stream composition is used for the equalizer part for analog disks.

The tone control with a defeet is carried.

The balance input in which high balance transmit and amplification of a purity are possible, and the power amplifier direct functionality are carried.

A Subsonic Filter, a muting, and the accessories circuitry of a balance control are passed, and the Source-Direct functionality which links all the input sources with the predrive stage directly is carried.

Rear
Internal De
Balance
Power Bottom
Power-source Chassis

Rating of a mode
Form Alpha-X balance integrated amplifier
<Power amplifier part>
Output power (20Hz - 20kHz)
Both channel drive
190W+190W (6ohm)
160W+160W (8ohm)
THD (at the time of an effective output) 0.003% or less (8ohm)
Cross modulation distortion (at the time of an effective output) 0.003% or less (8ohm)
Dumping factor 150 (8ohm)
Frequency characteristic (1W) DC-300kHz+0 -3dB
Input sensitivity/impedance Balance, Normal:1V/3kohm (1kHz)
SN ratio (A network) 120dB or more
TIM distortion (SAWTOOTH) Below a limit-of-measurement value
Slew rate }200v/microsec (6ohm)
Rise time 0.5microsec
<Preamplifier part>
Input sensitivity/impedance
(1kHz)
Phono man month: 2.5mV / 47kohm
Phono MC: 300 microvolts/100 ohm
compact disk, Tuner, Line, Prosessor, Tape/DAT/Play1-2-3:150mV /, 47kohm
Phono maximum permissible input
(THD 0.01%)
MM:250mV
MC:25mV
Frequency characteristic Phono man month: 20Hz-20kHz}0.2dB
compact disk, Line, and Tape/DAT/Play1-2-3:DC-300kHz+0 -3 dB
SN ratio Phono man month: 90dB or more
Phono MC: 75dB or more
Tuner, Line, compact disk, and more than Tape/DAT/Play1-2-3:110dB
Tone control The Bass maximum variation: }5dB (50Hz)
The Treble maximum variation: }5dB (15kHz)
Turnover frequency: 75Hz, 150Hz
Subsonic Filter 16Hz (-3dB), 6dB / oct
Loudness 50Hz:+6dB
10kHz:+4dB
<Synthesis>
Power dissipation 400W
Dimensions Width 448x height 160x depth of 441mm
Weight 28.0kg