SANSUI AU - α 507 nra

Commentary

Pre-main amplifier with Ultimate α -X balance circuit.

The Ultimate α -X balance circuit achieves an excellent operating environment in the transmission and amplification process from the input to the output of the initial stage, driver stage and final stage by raising the current margin of the driver stage to twice that of the conventional one and operating it in A-class operation.

The driver stage employs a NEW diamond differential circuit that can take out + - output without phase inversion. This has excellent current supply capability even for instantaneous input signals and suppresses TIM distortion, which is harmful to the sense of hearing.

A total of four dedicated amplifiers are arranged on the + and - sides of L and R of the output stage, and a NM-LAPT single push-pull system is adopted in which the speakers are dynamically driven from both + and - sides under the same conditions.

An α -X balanced power supply is used for the power supply.
The output stage is a balanced closed type, the first stage is an upper symmetric balanced constant current type power supply, and the secondary side of the transformer is a separate winding. The closed loop configuration is completely independent from the ground.

In order to minimize the generation of vibration, a new shape radiator is adopted.

By adopting an elliptical insulator, vibration is dispersed effectively.

Uses a power cord with polarity display.

Model Rating

Type	Integrated amplifier
Power Amplifier Unit
Effective output (10 Hz to 20 kHz Simultaneous operation of both channels)	80W + 80W (6 Ω) 60W + 60W (8 Ω)
Total harmonic distortion factor (at effective output)	0.003% or Less (8 Ω)
Cross modulation distortion factor	0.003% or Less (8 Ω)
Damping factor	150 (8 Ω)
Frequency Response (1W)	DC ~ 300 khz + 0 -3dB
Signal-to-noise ratio (A network)	120 dB or more
Dynamic Power	280W (2 Ω) 180W (4 Ω) 130W (6 Ω)
TIM (SAWTOOTH)	Measurement limit value or less
Slew rate	180 V / μ sec
Rise time	0.6 μ sec
Preamplifier Section
Input Sensitivity / Impedance (1kHz)	Phono MM : 2.5mV/47k Ω Phono MC : 300 μ V/100 Ω CD, Tuner, Line, MD/Tape1, Tape2 : 150mV/20k Ω
Phono maximum allowable input	MM(THD 0.01%):210mV MC(THD 0.1%):21mV
Frequency Response (1W)	Phono MM : 20 Hz to 20 kHz ± 0.2 dB CD, Tuner, Line, MD/Tape-1, Tape-2 : DC ~ 300 khz + 0 -3dB
Signal-to-noise ratio (A network)	Phono MM : 88 dB or more Phono MC : 70 dB or more CD, Tuner, Line, MD/Tape-1, Tape2 : 110 dB or more
Tone control	Maximum variation of Bass : ± 6 dB (50 Hz) Maximum variation of Treble : ± 6 dB (15 kHz)
Subsonic filter	16 Hz (-3dB), 6dB/oct.
Loudness	+8dB(50Hz) +4dB(10kHz)
<General>
Rated power consumption	160W
External dimensions	Width 432x Height 165x Depth 450 mm
Weight	15.5kg