So I've always had this problem when e.g. sending a backing track through my Kabinet. I used to send a backing track from my computer's 3.5mm out to the Kemper's aux in. This works great when playing through headphones. I get both right and left channel through the headphones. This works.
When I want to play through my Kabinet however, I only get the left channel from the aux. I have:
Aux >Mono : Off
Monitor stereo: Off
This gives stereo through headphones but L channel only through Kabinet.
If I switch to:
Aux >Mono : On
Monitor stereo: Off
I get instead Mono through headphones and both channels (mono) through Kabinet.
This was fine and I basically never used both the headphones and the Kabinet anyway. I just ticked that box whenever I changed between them.
However, we now have audio over USB and I have no mono option left. Am I missing something in my setup? All I want to do is play some Spotify via USB through my Kabinet.