One more question, Stephen:
You mentioned, you use the 16 and the 8 Ohm sources.
How is your cab wired? If you plug it into the 16 Ohm output, is it serial with two 8 Ohm speakers?
But then, using two 8 Ohm speakers parallel, you usually plug it into the 4 Ohm source, not the 8 Ohm - am I...