i hope i am asking this question correctly.i have noticed that my mark 4 definatly has a sweet spot for tone.mostly when pushed pretty hard.are the different power stages on the mark 4 there so you can acheive that sweet spot at various volumes?if i run the amp class a,triode,tweed power..will i achieve the sweet spot tone at a lower volume than,pentode,full,simul?or are the different power stages something that just helps you achieve different tones completly?i know this is prob a novice question,but maybe someone could articulate it for me better.thanks.