the Sansui D series was the regular/commercial line of Sansui hifi that competed favorably with other brands in the US. it's the line that got the world market convinced that Sansui is no hifi pushover (a dedicated Sansui thread in Audio Karma is proof). the premium line during Sansui's prime was the AU-X... series which tried to recapture the tube sound, but with better specs/figures. the Alpha was the last line of Sansui premium hifi - sort of last hurray, so binuhos na ang kaya nilang gawin. since it was manufactured with the best SS components/technology, it was released mostly in the domestic market which has higher purchasing power. Europe had a few units distributed but none in the US and other markets. also the highest Alpha model sold internationally, (901, 911, etc.) was equivalent only to the Alpha 707 series. Alpha amps are quoted highly even at used market, over $1K used for Alpha 607 in the US. my 1995 Hifi Choice has a quote of Alpha 707 at 1,600 pounds brand new (it came our in Japan in 1987) and was even rated by reviewers better than Aleph Pass and some Audio Note amps. they should have reviewed the Alpha 907 series, especially the premium models, which still command an average of over 100,000 yen ($900) used in the Japanese market. the Alpha 907 (original model, same as my unit) was selling only up to 40,000 yen used, the bottom line of the Alpha 907 series.