I've just stumpled across this whilst looking for a simple vcf circuit and I like what I see. I'm just getting going on making my own noise makers, I've read Nicloas Collins Handmade Electronic Music so I've done simple things with the hex schmitt trigger. I'm sure I can gain a lot of info from this schematic. I'm going to try my best to get this onto strip board, but if I fail I'll be buying one of your pcb's when you make them available. Cheers