I cannot believe it! after ALL these, the PSU was to blame!!!!
I used a mATX 300W PSU with an amigakit.com converter!
it turns out that PSU is total crap, because it cannot deliver enough watts for either 5v or 3.3v , dunno which...
I tested with the normal 140W A4000 PSU and _EVERYTHING_ works perfect!
so, remember, always use High Quality PSU's , and when u start getting sound/aga probs, check the PSU first...
thanks for all your support!