Hi. My wife's decided I need a new amp. We go in the store, she points to the SM-500 and states " That's your new amp. " I'm replacing my Studio 220 that powers an original Goliath cab. I've read the recent thread about the 750x vs the SM-500; my main issue with the 220, besides blowing it up three times, has alway been lack of power. Looking for some advice.