I use a Line 6 Helix guitar processor and I like to run it through my PreSonus Audiobox USB interface. I do this for at home practicing, creating guitar patches, etc. I am not going through a DAW or anything. I run 1/4" L and R outs from my Helix into the 2 inputs of the Audiobox. The problem is the signal is in mono, and after a bit of research, I discovered the inputs on the Audiobox cannot be monitored in stereo. Is there another affordable interface that will allow me to monitor in stereo?