Can I plug a different instrument into each of the inputs of my PowerStage 100s or PowerStage 700?
Yes, the instrument that you plug into the Left input will be heard in the left speaker out or direct out and the instrument plugged into the right input will be heard in the right speaker out or right direct out. There is no "pan" control in the PowerStage 100s or PowerStage 700 to sweep a signal from left speaker to right speaker.