The AU-919 is simple superb and deserves all the accolades and reputation it has. Sound I would describe as pure, it gets out of the way and just lets the music come through.
It is indeed regarded as
one of Sansui's best ever but there are other Sansui amps that have a similar rep too.
The AU-X1 is one of those. Sansui took the 919 close to the limit in terms of slew rate etc and it has one of the widest bands widths ever.
With the AU-X1, Sansui pushed things further, to the limit and some which meant stability issues with early models.
It was the flagship between 1979-83.
'Quote'
"It is one of the mightiest and best sounding amps of its time - and beyond. 160 wpc rms at 8 ohms, weight almost 28 kg. More a power amp with controls than a conventional integrated amp, but it has phono MM/MC and many other in-/outputs. Lacks tone controls, though.
Some (first version) tend to have oscillation problems, others (later) don't. One of the best amps ever."