How do I set the Solo Voice on SuperKar+ to always be in tune?

Set the tertiary Solo CV adjust to maximum, and it will quantize the Solo Voice to half-steps so that it is guaranteed to be in tune with the chord voice. Adjust this setting by pressing and holding the left TIMBRE button and turning the SOLO DAMP. This will make the Solo Voice immune to CV errors, but the voice can still be varied via the Pitch CV.