can anyone tell me the changes when this amp was upgraded or revised.are there any significant issues i should beware of or pros n cons between the 2. see im shopping for my first head im an amuture at best whos working up to his first gig..im getting alil Tim the tool man growl for power. i have a nice ampeg 210c thats powerful. im just gettin power hungry gggggrrrr!!!!!! thanks chas