Eclipse can use a mono in/stereo out or Stereo I/O setup, depending on what type of audio are you feeding it.
Example:
if all the unit needs to process is a mono signal, like the one coming from a guitar/preamp, Eclipse INPUT MODE can be set to Input 1 or input 2, under LEVELS. If Eclipse will instead process a signal that is already stereo, like an already effected one, then keep INPUT MODE on STEREO and use both I/Os.
best
I
