For the project I used different sources for the PCB's, dependent from the complexity of the schematic. It make no sense to develop all circuits new, because there are 70years of experience in analog synthesizer available on earth. Therefore I used also finished circuits from different webpages or books.
For the VCO (voltage controlled oscillator) I bought 2 unassembled PCB's from the MFOs Webpage, because this is the complexist circuit and otherwise a project in itself. The other PCB's I was etching and assemblied by myself.
As following you will find a simple way to manufacture PCB's by self.