Sansui AU 999 vs. 9500
Hi allstar856 and welcome to AK and Exclusively Sansui.
Here is a link to The Best of Sansui, if you haven't yet discovered it, so that you can find out about the integrated amps or other Sansuis.
http://www.sansui.us/Amplifiers.htm
I have both the 999 and 9500. Both are wonderful. The 9500 has a great build quality. It is built like a tank and it is also the more powerful of the two. The 999 has 50 rms watts/channel into 8 ohms, the 9500 is about 80 to 85. Both were TOTL in their day and are said to be the Sansuis with the most tube-like sound.
My 999 was my recent acquisition and I love it. I haven't yet taken the top off to see what it looks like inside but if you look at the picture on best of Sansui, the 9500 is more substantial. My 9500 developed a hum and probably needs new power caps. It was supposedly checked over by the eBay seller and brought up to spec when sold to me, but with both of these amplifiers a complete recap, if not already done, likely should be done in the near future. I can't fairly compare the two now, but the 9500 didn't sound that special to me when I first got it, the 999 does. I would guess this may be more a matter of the condition of their aging components rather than a reflection on the sound of these integrateds themselves when either new or recapped. Having expressed my preference for the 999 in my collection, I must add that when I do blinded listening with a switchbox, at my level of listening (not very loud), I can't tell the difference between most of my integrateds (AU 999, 9500, 11000, 717, 919, D11, D11II).
The 9500 looks fairly easy to work on yourself if you are so inclined, and I suspect the 999 is too. One other thing to keep in mind is that the price of all Sansui TOTL models seems to have increased sharply over the past 6 months and the 9500 has gone up significantly in price. Unless you can get a great deal on the 9500, the price of this model on eBay lately puts it into the range of the newer and somewhat more powerful integrateds.
I can't fault you for wanting an AU 9500, I wanted both, but I'm not sure that you will notice the difference unless you need the extra power. Recapping your 999 is also an option.
Hope this helps.
Marc