I emailed Ampete and they replied with below….
I think there is a misunderstanding, two heads will never feed one cabinet, but only two (except for a speaker cabinet with stereo functionality of course). In the stereo mode the 442 will route two heads simultaneously but separately into the two cabinets. In the “rig” mode, the speaker signal of the amp is not routed back in the switcher but drives a speaker cab that is directly connected to the amp/combo, that runs in rig mode.
Let me know if that clarifies it. What’s the forum?
Peter Arends
Ampete Engineering