@Mick : So it's hard, it's production of Synthesis , i have friend own amplifier and tell him "Could i open it's and see and draw schematics ?" , him accept and bingo
If you can winding OPT , i have winding design and turn number , you need to EI96 laminate with stack heigh about 5-6cm
We need 2600 turn ( dia 0.2mm ) split to 4 layer in primary and 6 layer seconary with 36 turn on each layer.
When you finish , you can solder secondary wire follow : S1 // S2 // S4 serial with S3 // S5 // S6
Sorry for my english , i'm vietnamses and i speaking english not very well . Hope you understand