I've seen that the mesa lonestar amps can switch from 4 output tubes to 2 then 1. I'd like to know how this works. Switching from 4 to 2 still keeps the amp operating in class AB but doesn't switching from 2 to 1 make it single ended therefore class A? Am I incorrect thinking that output impedences change switching from full power to half power as well as class A operation requiring a different type of output tranny than a push pull. Please educate me.