Thank you all!
The more I go ahead and the more I enjoy this, but the more difficult it became 
Now that The SCC works reasonabily, I had to fix the AY-3-8910... noises and envelopes were buggy.
I could fix some functions and simplify the envelope generator with a look-up table.
I have uploaded the update and the audio should sounds more complete since some drums are played by the PSG.
Unfortunately the overall speed is decreasing, so some optimization of the code has to be done.
So, thank you very much for your support!!!! 
Thnak you Guys for your support!
A new update is available.
You can choose now some parameters and titles divided by ROM Mapper type...
So, if you want to play one, just choose first:
tv blur, more functional on doubled scale, Scanlines, and video scale...
then choose the title...
Actually you need to choose parameters for that box, sorry 
You will ear a "creepy" sound, sorry... I'm still working on an accurate and clean audio stream... but at least this is STEREO! Uhm, not at all It's just a simulation, i exchange rapidly some channels from left to right to simulate a stereo separation.
It's nice on King's Valley II
Hope you will enjoy!
MSX2 is too much for me now But maybe in the future I will implement it too...
please, fix the "envelop period problem", that is not a sound-buffer-related problem, it is a bad emulation of msx native soundchip.
Updated now some titles like Pac-Man sounds more similar to blueMSX, Mess ( my terms of comparison are those )... fixed volume handling and envelope period of AY 3 8910, the SCC has to be still fixed. Improved the second audio buffer, but of course there is some latency, so when you "fire" the sounds came after a while of course..
Actually to my ear is not too bad, but of course your opinion come first! 
Sorry, maybe I uploaded a wrong version Sorry again... now it should work!
But I saw that some games doesn't start... maybe the functions that checks thekind of Rom mapper miss something. So I need to check every game one by one
So sorry me if some on won't start.
Actually I have fixed I hope the sound... Rebuild a look up table on the AY-3-8910 volume amplitude, according to this formula:
Amp = pow ( 2, − ((15 − n) / 2) )
and the SCC look up table is linear...
( found on en.wikipedia.org/wiki/Konami_SCC )
I tryied to normalize max audio amp to 1, on both chips out volume but this is becoming difficult since I still need to find a way to check the exact output level for each chip. Now happens that SCC is stronger than PSG even if the out value is max 1. ( I write 1 as a float number inthe master audio stream )
However I need also to imptrove the handling of the second buffer for a more detailed audio. So much work but funny.
Better. Sound is still not 100% indeed. PSG sound is a bit off sometimes, and it's definitely lagging. Try Bosconian with the "Blast Off!" sample... the sound in King's Valley II is also quite different than the original (throw a sword). And I noticed that The Maze of Galious doesn't run at all.
Still, quite an amazing achievement! Keep it up