[/IMG] help me understand these knobs and buttons. 1) the -10db button by the input. what is it for? all i can tell is it just kills the output. 2) why is there a volume and a master volume? would you ever have one up more than the other? 3) level????? basically sounds like it gives it a little more output and a little more punch but seems to distort as you go higher up. 4) what in the world is frequency? 5) what is the footswitch input for?