So Ive found myself in 2 bands that are both using inadequate PA. Im not real keen to stump up for a whole system myself and even less keen on the band buying one. Im leaning more towards suggesting we each buy a component. Im thinking I can buy the power amp and a sub. Is there any difference between a PA power-amp and the power amps in rack-mounted bass rig? Is there a PA sub I can buy that would double as a stand-alone bass cab if needed? Im thinking that if/when the bands fall apart I can just use what Ive bought as my bass rig. This has probably been covered before but I had no idea what to search for.