Hello, I have a Yamaha bass guitar - a fairly basic one thats plays nicely. It has the style of p/u that is two separate ones side by side (one on E & A, other on D & G). Is this a 'J' p/u? How did they receive their names? It wasn't a very expensive guitar but I enjoy playing it and would like to upgrade it a little. I am interested in changing the p/u. How much difference do they make? Why do they make a difference? Will I be able to replace it myself with a soldering iron, screwdriver and an IQ of around 117? I'd like a clean, rounded, plenty of bottom end style tone so are there any specific ones you would recommend? I have done a search, but I'm sorry, I got a heck of a lot of results, most too technical for me, and still no really basic info like "What's this p/u called?". Thanks for your help.