Q1: When I use a mono pedal in the Duophony's FX loop, the sound on the outputs appears only on the Left channel, there is no sound on the Right channel. How can I make the sound appears on the Right output channel as well?
A1: To duplicate the signal on the Left channel to the Right channel you need to use a mono-to-stereo converter cable like this:
Connect the TS side to the output of your mono pedal, and the TRS side to the Return jack of Duophony.
Q2: The bottom-half of the mix slider control doesn't seem to be responsive.
A2: It may not be immediately obvious, but the sensitive part of the touch pad is actually the grey semi-circle strips, and not the light-emitting strip. By intuition, we tend to slide the finger on the light strip instead, which works ok for the top half, because the finger will more or less still touch the grey circle. But for the bottom half, the sensitive area may not be receiving enough finger touch. Therefore, when working with the bottom half of the slider it is advisable to work your finger on the grey semi circle instead.