SANSUI A - α 7

Commentary

This is an integrated amplifier of the Alf series that compactly condenses the technology of the AU - α series.

In A - α 7, a combination of a diamond differential circuit and a Uilson current mirror circuit is generically called an advanced diamond differential circuit.
By installing a diamond differential circuit in the power amplifier, the last stage power transistor (LAPT) can be driven with a sufficient margin, and the rise characteristic of the signal is improved, so that it can be used even in the rapidly changing digital source.
A Uilson current mirror circuit is used in the first stage of the power amplifier to suppress the circuit noise generated in the first stage and improve the quality of the amplifier as a whole.

The diamond differential circuit has a structure in which four transistors are operated symmetrically with each other to obtain a powerful current. This is a high-speed and high-current response circuit unique to SANSUI. By adopting this circuit in the pre-drive stage, instantaneous current supply capability to the driver stage and final output stage is improved.

By adding a Uilson current mirror circuit to the input differential amplifier circuit, the current flowing through the two amplifying elements can be made equal. By using this circuit in the first stage of the power amplifier, the current flowing through the amplifying element is always kept constant, and noise caused by temperature change or asymmetry of elements is suppressed.

The twin monaural power unit configuration improves the separation between L and R, reduces crosstalk, and eliminates the mutual interference between L and R.
In addition, insulators and side panels with excellent vibration damping characteristics prevent deterioration of sound quality.

The output transistor uses LAPT (Linear Amplification Power Transistor) to improve the high-frequency stretch and response to sound.

The power transformer is equipped with a dedicated heavy-class EI transformer from Shinkai, which has gentle saturation and is suitable for obtaining strong sound quality.
New improvements have been made to the electrolytic capacitor to achieve high sound quality. By using a newly developed acoustic conversion coating, defects inside the film have been reduced by 30% compared with conventional ones. In addition, by using the new chemical conversion method, carbon content in the electrolytic solution has been reduced by 32% compared with conventional ones. In addition, we have developed and adopted an electrolytic solution with less impurities.

Rotary 6-input input selector is used.

Equipped with a CD direct mechanism, the transmission path of CD can be minimized and input directly to the power amplifier.

Equipped with 3-mode presence control function, volume balance can be adjusted according to listening condition or combination of speakers.

It uses a screw-type gold-plated speaker terminal that is compatible with banana plugs.
Gold plated terminals are used for all input and output terminals.

It has a processor jack that can be connected to a surround processor or an equalizer.

A 32-key remote controller with CD, DECK and TUNER control is included.

Model Rating

Type	Pre-main amplifier
Effective power	60W + 60W (6 Ω) 50W + 50W (8 Ω)
Maximum practical power	85W + 85W (EIAJ, 6 Ω)
Total harmonic distortion factor	0.008% or Less (1 kHz)
Frequency characteristic	5 Hz ~ 100 kHz + 0 -3dB
Damping factor	135 (8 Ω)
Signal-to-noise ratio	CD Direct:102dB
Input Sensitivity / Impedance (1kHz)	Phono MM : 2.5mV/47k Ω Line : 150mV/47k Ω
Rated power consumption	110W
External dimensions	Width 284x Height 125x Depth 370 mm
Weight	7.8kg
Sold Separately	Sidewood SW-AD7 (¥ 5,000)