I myself was lucky enough to pick up the Sansui AU-9900A from a friend of mine. This is a 220volt model/multivolt model, made for international markets i presume. The amp itself runs OK, not in bad shape, there were also couple of issues which i helped my friend fix before i made the purchase. The history of issues which were present in the 9900A are the following: 1. One non working phono channel ( this was a dry solder in the phono board for the 5 leg transistor). I managed to get the output working, but then crept up a newer problem, the output on the fixed channel was noisy and grainy. Attributed to the same noisy transistor may be. 2. One could literally boil water on top of the amp. The biasing was set very high and the amp sounded horrible producing enormous amount of heat. The amplifier was then re-biased and it sounded so much better. 3. There is though no thermal grease on one of the TO-3 transistors, literally no grease present at all. 4. I do believe on of the TO-3 transistors installed in the amp is a replica and not authentic, just by looks on how it looks like this is what i could presume. I don't think i could even find the original output transistors, probably the On Semi MJ21193G and MJ21194G are the best replacements available. I have also checked Hyperion(John's) and Dr.Audio's posts and do have some idea on what i am looking at. The differences between the 9900 and the 9900A, atleast from driver board which i can make out is the missing offset adjustment. In paper the 9900A has a THD of 0.05% vs 0.08% of the 9900 and also a better frequency response compared to the 9900. I plan to restore the amplifier to good working condition, better than it ever was, and i would like inputs from fellow senior members. I have also decided to give a break for my AU-X11 restoration, which in fact is running in good health and shape. And finally yes the serial numbers will be added to the AK database. Pictures will be uploaded soon.