At first, thanks for reply! You were right, I did not read the manual (I hope it's not too late ;)). The price of the components can be problematic for me, because I'm a 16-year old student. I'll manage to build this, even it will last a year! I've obtained a C64C and a C128D recently, but in both are 8580 chips. So I will keep on seeking for a 6581. The design is not a problem. I've decided to build this synth into a C16 case (looks like C64, but is black). I can make the faceplate without problems, because we have some hobs/millers (I don't know which is right) and other stuff at the school. BTW I attend the Secondary Electrotechnic School of S. A. Jedlik. Jedlik invented the electric motor, the dynamo-theory and the dynamo too - altough Siemens has patented it. So... I will keep on working on my MBSID hard as possible (without decreasing my performance in the school), and when I get some results (actually a working MBSID w. control surface), I will upload them. Greetings from Slovakia (btw, I'm hungarian, but i was born in slovakia and still living here)!