Thanks for your reply.
I can certainly understand the fact that the vol and source knob bothering different people to different extents, BUT:
how can this be a "part of the design"? you mean they designed it on purpose in such a way that the vol knob will have play and the source knob misses the sources selected? I would think this is a failure or an error in the design/construction, but I don't understand how this can be explained as part of design.

all that said, I'm one who value SQ more than anything else, so it's probably not gonna bother me much either...I'm leaning heavily towards ordering a B stock right now..
But I will not try to make it better by saying that it isn't a flaw in the design/parts. it is just that. Learning to live with it is what should be done, but not make it look like it was intended that way.
I probably read all the professional and non professional reviews available online now...none of them thought these 2 flaws mattered enough to not own the amp. But none of them thought it was normal in any way either.