A Eurorack VCO powered by AS3340
- 40mm x 99mm single PCB design (so very cheap to manufacture)
- Lots of standing resistors and diodes to help achieve this (so it's a super crowded PCB)
- See BOM info here
- 1v/Oct In
- CV2 In
- FM In
- Sync In (selectable between hard and soft sync with switch and settable between positive hard sync (default) and negative hard sync with a jumper)
- PWM Control In
- Sawtooth
- Square
- Triangle
- First batch of PCBs arrived and 1 built. Working and tunable.
- Lots of standing resistors to maximise soldering challenges
- 3d printed panel designed and will be tested soon
- Use this design at your own risk
- Pay close attention to the iBOM to get the right positioning
- Make sure you do the components under the ICs before you solder the IC sockets
- Start with the shorter components and work your way up (I started with resistors and diodes)
- Do panel components last (and ideally mount on panel before soldering to get best alignment)
- The digisound guide was helpful in tuning. Focus on getting the relationship between 1v/octave at lowish freqs with trimmer 2 while octave switch is off. Then use trimmer 1 to tune with keyboard with the fine tune pot in the middle position. Trimmer 3 can be used to adjust linearity at high freqs.
- Some resistor values need updating in BOM
- Holes for toggle switches are slightly too close tigether so legs will need bent to fit until footprint is updated.
- Footprint for poly timing cap could be much bigger
