This is an attempt to design a Mono > Stereo Snd/Rtn + Dry/Wet & Pan Control patch. Haven’t tried it, but I think it works:
Audio Signal path: Oscillator > Filter > Splits to Dry/Wet (Snd/Rtn)
Dry (Snd) Audio Signal path: Filter > Panner > VCA_1 (Left) &VCA_2 (Right) > Stereo Mixer_1 > Output Mixer
Wet (Rtn) Audio Signal path: Filter > VCA_3 > Mixer* > FX > Stereo Mixer_2 > Output Mixer
Fx’s balance pot is always fully Wet because Dry follows another path*
Dry/Wet (Snd/Rtn) is now controlled by Attenuator’s pot:
Dry/Wet (Snd/Rtn) Balance: Attenuator > Splits to control Dry/Wet (Snd/Rtn)
Dry (Snd): Attenuator > VCA_1+2 (inverted)
Wet (Rtn): Attenuator > VCA_3
Panner’s pot controls L/R for the Dry signal
More voices can be Snd/Rtn to Fx by the same way.
*According to my tests Fx inputs are Stereo only for the Dry Signal. For the Wet Signal they are summed to Mono. Therefore, and as the Fx is always fully Wet Fx’s inputs doesn’t have to be Stereo. A Mono Mixer will have the same results.
[Updated: Click on image.]