I have spent hours and hours on my one, I can work on it with my eyes closed, I don't need to necessarily work on many of them to see how the design is, how they are constructed and find the idiosyncrasies....they are a good amplifier and the design is solid and reliable for such a high speed design. The only thing that I found annoying is the way Sansui designed their Over-current protection. Its a static threshold which trips the protection at 220watts @ 8Ω. I have removed the detector diodes from mine to disable it, and also from the G9000. Music is dynamic and as soon as there is a peak over the static threshold, then it trips the protection, well before the RMS output is anywhere near the danger area. Small nanosecond peaks such as this will not damage the amplifier, they might if subjected to that particular level for a period of time. What they should have done is some sort of limiter circuit that allows the peaks, some sort of look ahead limiter that clamps the rails to prevent clipping and over-current damage.....If you run 4Ω speakers, the over-current protection is extremely trigger happy and its gets really annoying.
It is true what Paul says though about the pre-amp. I like the way Sansui used the lever switches for almost everything, as they are easily dismantled and the tarnish cleaned off the sliver plated contacts.
The CONNECTED/SEPARATEFD switch is a weak point, its very very difficult to get to, and they invariably always cause dropouts.
But you can basically bypass it by coming out of the pre-amp output on the side instead of the output on the back of the pre-amp if you get sick of cleaning that switch every year or so...
The want is always greater than the need, but for these units, they are going up and up and up and up in price, they are rare, they sound stunning, and its definitely worth getting one of you can.
I was lucky to be able to buy mine back after I sold it 6 years ago, its never ever leaving me this time. I think it may be the only one in New Zealand!!