I don't know if I am quoting or not but referring back to the Heath Apache (E.F. Johnson Valiant and Viking 500 also could use a SSB adapter) The Valiant had 3 6146'es The Apache had two like the Viking 2. I am trying to remember the difference tuning for class AB 2 I believe because on voice peaks I recall just barely drawing a couple ma of grid current, a resting plate current of maybe 60 ma. To tune for SSB you would unbalance the carrier null and peak the various stages including the driver stage in the adapter and try to get a little grid current on the finals. The Plate Had a shallower and broader dip than in Class C and when that was close you could peak all the other stages by max plate current although I think there was an rf out meter as well. The regular class C Am/cw tuning was 6 mils grid current and 120-150 Plate (actually plate and screen) no resting current in class C obviously. The 500 had a "tune " position I don't recall but the Apache may have also. JIM