Hello customsforge friends :D, hope you all are having a nice week.   I've been thinking about upgrading my Peavey Rockmaster (cheapest guitar ever), I've been thinking about buying a EMG pickup, but I'm not sure which one to buy...   I don't fully understand the difference between passive or active pickups... the guitar already has a bridge pickup which is not bad, but I'd like a better sound...   I've been trying to pick from these two, the H4 and the H4a   http://www.emgpickups.com/guitar/hum