'nampeg ? Is that the one from over seas ?
sorry , I couldn't resist...
my advice. Set everything flat. Dial your tone in close as you can get it with the rotary EQ (Bass Mid, Treble) - then use the graphic to make minor adjustments.
Assuming that you like the basic sound of your bass and of your cabinet - that approach will get you home. If you find yourself making gross adjustements with either the rotary or graphic EQ - then it's time to be thinking in terms of Is this the right bass ? Is this the right cab ? Is this the right head ?