1001 Hi-Fi Info: SANSUI AU-alpha907NRA (1998)

A flagship model that will create history in sound. The pinnacle of integrated amplifiers, the "907" models have changed throughout the years. Now here is the AU-alpha907NRA. Equipped with the Ultimate Q-X balanced circuit, which brings together the best of Sansui's original technology. The current margin of the driver stage has been doubled to Class A operation, and the circuit itself has achieved outstanding dynamic characteristics and wide range and high speed in all transmission and amplification processes. The final stage has been changed to a single drive balanced push-pull configuration, and is equipped with a NM-LAPT with Pc (collector loss) of 200W, which is suitable for high power amplification, which was used in the power amplifier B-2302. The powerful power supply section uses a high-performance power transformer with a total weight of 13kg. By sealing a high-density filler inside the four-layer shield, vibration during operation has been suppressed and the stable current supply capacity has been greatly improved. The capacitors, film capacitors, and resistors are of the highest standard, developed for Sansui's VINTAGE series, and are used in an ideal combination. The speakers are connected to terminals made of OFC alloy and 24-carat hardened gold plated by WBT of Germany, which has little signal loss. Banana plugs are also supported. The pure copper elliptical insulators made of genuine leather, which provide excellent vibration damping properties, and the volume knob machined from solid aluminum are all carefully considered to maintain the purity of the sound. The music signal is transmitted and amplified with high purity by connecting it from input to output in the shortest possible distance. The signal connected to the three direct inputs is sent directly to the power amplifier section without passing through the preamplifier circuit. In addition, a balanced input terminal is also provided, allowing you to create an ideal balanced operating environment for the entire system. A new heat sink with an elliptical hole on which the power board equipped with the isolated mechanical feedback steel plate and the Ultimate X-Balance circuit is assembled. In the 907NRA, the power transformer, the largest source of vibration, is mounted floating from the chassis. This isolates the power supply system from vibrations and eliminates mechanical interference. In addition, the heat sink, which acts as a resonating plate when mounted directly on the power transistor, has been thoroughly redesigned to effectively disperse the resonating effect. Combined with the reinforced twin mono construction that structurally controls the vibrations of the power supply and signal systems and the isolated mechanical feedback that effectively blocks the transmission route of vibration, this complete vibration countermeasure realizes ideal sound field performance. Good Design Award winning product.

Main specifications

Power amplifier section 160W+160W (8oHm)

Total harmonic distortion (at effective output): 0.003%

Damping factor: 150

Frequency response (1W): DC~300kHz

External dimensions: 462 (W) x 165 (H) x 448(D)mm

Weight: 33.0kg