The Sansui AU-111 is an integrated amplifier that was first introduced in 1965 and remained in production until 1971, showcasing advanced tube technology. It features a fixed bias 6L6-GC AB1 Push-Pull output stage, designed to extract the maximum capabilities of the 6L6-GCs, operating at a plate voltage of 485V. This design yields an RMS stereo power output of 40W per channel with total harmonic distortion (THD) measured at less than 0.8%. The control section includes a cathode follower first stage along with three amplification stages, equipped with sophisticated tone controls, low/high filters, loudness, and presence switches, although the tone circuit can be bypassed via defeat switches. The phono equalizer portion employs a solid-state circuit to enhance the signal-to-noise ratio at low levels. The AU-111 was notable for introducing Sansui's distinctive black front panel, setting a style that would continue for over two decades. Over its lifetime, several revisions of the AU-111 were made, with the first generation being particularly rare. Later, in 1999, Sansui reintroduced the AU-111 as the AU-111 Vintage, leading to further iterations designed for modern audio formats. Significant specifications include the use of vacuum tubes such as 6L6GC (4), 12AX7 (5), and 12BH7A (2), along with transistors, and a frequency response of +1-1dB from 20 to 50,000 cps.
