Recently got a Synth Rotek Atari Punk Console kit, and built it wile this case was printing. I decided not to use the included kit knobs but these old 1970's solid aluminum radio knobs.
The top knob is volume, the other two are the occilator adjustments.
The three 1/8' jacks are two CV inputs and audio out. I also put the 1/4" output jack on the back. Depending on your printers accuracy you may need to drill out the holes a little for some componants.