Its got a passive feel when you play it but you get a clearer tone compared to a passive set. I like them on my gibson les paul coz the worn gold covers blends perfectly with the goldtop body. I like to split the neck pup for cleans.
I just got a regular Modern set, and they can be split. If the Adler set has solder pads labeled "CT" and "H" then they should be able to be split. I've been searching to see if a guy can use those pads to go between series and parallel, that way you get a single coil-ish tone (more fat, more like a P-90), and you don't lose any output, and they deal with him better. But like somebody said above, they are supposed to be really quiet in single mode, so that shouldn't be a concern anyway. I just like the parallel tone better than split.
ETA: Did some further searching and found out that they can't switch between series and parallel, so that question is answered. But upon looking at that diagram some more, the bottom version is called inner/outer coul tap. I'm kinda confused about how that one works.