Got this article about Sansui AU 111:
AU-111 was the ultimate tube amp Sansui ever produced. This was the Sansuiās technical submit of its root transformer production. Also, in circuit design, Sansui adopted the latest of many years of tube technology. As the result, sonically, I don't think there is not much room to improve.
Sansui has been a company that improves its products step by step. The early Sansui transistor amps, such as AU-999, AU-9500, AU-9900, AU-919, and AU-D11 all sounded like trying to be like tube amps, and never got there. Sansui stated to change that from AU-D11II, AU-G99X, and AU-X701(this was AU-Alpha607 in Japan (1988)). The high frequency of AU-X701 is so sensitive that Sansui has succeed to go to the root of tube technology; however, they were definitely weak in low compared with tube amps this is nothing more than comparison, I still like the sound of AU-G99X and AU-X701 much better compared with today's expensive transistor amps.
By knowing this Sansui tradition, the astonishing resemblance in sound between 907MR and AU-111 tells me that Sansui might have been designing its amps to reach the ultimate sonic submit they have already reached thirty years ago. Even, they might have been using AU-111 as a reference amp for their goal. I can ask those questions to those Japanese engineers whom Mr. Motoki has introduced to me.
This suspicion also coincides with what Sansui did. As I said, Sansui has been a company that always tried to improve the product by one step at a time. The last high-end integrated amp Sansui ever produced was AU-111G in 2000. This was AU-111 specifically redesigned on the pre-amp section for SACD and DVD Audio use. By considering the Sansui tradition, if AU-111G had not sounded equal or better than AU-Alpha907NRA, they would not have introduced AU-111G. This thought process and the result of my test also tell me that Sansui finally archived its goal before it ceased to exist in high-end audio market; to produce the ultimate transistor amp that is equal to the best tube amp Sansui ever produced.