1.How is the Strings section when compared to Tyros2? Is there any improvement in strings voices?
No improvement over PSR3000.
2.What improvement in S-900 regarding vocal harmony feature overpsr-3000 and how the microphone sounds in s-900?
Mic gain is little better. Harmonizer seems the same.
3.How the Aux output sound with connected amplispeaker system?Is it sounds better than psr-3000 Aux output?
I don't know.
4.Is the styles sound same as Tyros2?
They sound significantly improved over the PSR3000. I had never heard the Tyros 2.
5.What is the difference between PA-300 and PA-300B power adaptors?
Nothing.
6.Your S-900 keyboard manufacturing country.
I'll check later.

SUNNY.[/B][/QUOTE]