Seen maybe a couple of each for sale before, they do not show up often. I don't believe Sansui had any US distribution at all in the era these were made. Which is to say that they are exceedingly rare. They are interesting as examples of earlier tube based efforts from Sansui (before their ascent to becoming legendary the world over) but can't say I have ever been inclined to seek them out for my collection.
Not to knock on these certainly, but I hold the opinion that the true age of Hi-fi began about the mid-late 1960's. The AU-111, BA-202 and BA-303 would be of much more interest to me than these earlier models. I say that because much was still being learned and put into practice in the mid-late 60's in regards to good sound reproduction both in tubes and solid state. Output power ratings also increased in that era to a point where better results could be attained with difficult speaker loads. I know some guys swear by 5W single ended triode amps, that just isn't my scene. Yes, I'm a power monger, so give me a tube amp that can hit at least 30WPC, I can work with that. For solid state? Well, I like the 125-160WPC range a lot.
Certainly there is stuff that sounds good from the 50's and early 60's, and while that era of gear is not really on my radar I admit to sometimes being surprised and impressed by some of the stuff from that time frame when I do come across it. I guess I see them more as antiques than pieces to see regular use for serious listening. I know that probably sounds stupid, but being born in the mid- 1970's my taste in equipment is heavily influenced by what I grew up seeing and hearing.
I don't think anyone can say that Sansui didn't really hit their stride until the introduction of the AU-111. After that, they made the big time pretty quickly and the 2000-5000 series receivers cemented their reputation with the public in the late 60's concurrent with Vietnam and all the military guys who brought back pallets of the stuff. From there we all know the rest of the story.
Nonetheless, one can see these are quality built pieces, at a time when Japan was still largely derided as a source of cheap trinkets more than serious equipment of any sort. Really, one has to wonder how much an outfit like Sansui influenced the drive of Japanese industry to build really excellent gear. There were many others certainly, but Sansui seemed to take this path earlier than most. Their design philosophy appears to have been adopted by many Japanese companies - in electronics and otherwise - with the result being that the collective industries of that country turned in a powerhouse of exporting some remarkable stuff while their economic fortunes were still good. Of course, then the 1990's happened and much damage was done to their ability to continue offering such products.
Kevin