ok, so i have my Marshall half stack, its a jcm2000 DSL head and i have the 1960 B or A cab, (not sure) But anyways, it sounds pretty good on lead 2 but whenever I turn it up to 3 volume or higher, the sounds gets more muffled and sounds like its not as clear and crisp. It seems to have less high end also, kinda like the presence is lowered. Why is this?