Next to the VCF section is the ADSR and AR section, which I've finished now, too:
Main Board, ADSR and AR Completed
Jacks and switch still missing, sliders and button installed for testing.
Jacks and switch still missing, sliders and button installed for testing.
Powering up again, connecting the according ADSR and AR outputs to my oscilloscope and pushing the button shows the following waveforms (after some fine-tuning of the sliders):
This looks pretty good, I think.