what's up yall. a friend refered me to this forum. i have a 5150 II that i bought used a long while ago. Now, im thrilled with the sound i get from my cab (marshall 1960a) at low and high volumes. however, after going through this forum, i keep reading about biasing the amp. I've never really even thought about it. I see it has the test points and a little bias pot right behind the grill. First. why should i do this, and what should i look/listen for? Second. how do i do it?