Why is this the way it is (diagram)?

[spauldingrules]

http://www.seymourduncan.com/wp-content/uploads/2015/05/EAX_1V_1T.jpg

So why do they have the red and black wire from the middle pickup connecting to the selector switch?

Also, why do they have a wire going from the last lug to the first lug on the other side, then to the pot, rather than straight to the pot? 

I just wired mine straight to the volume, and with just the black wires, and it sounds fine.  What am I missing?

 

[Logrinn]

The middle pickup seems to be connected in parallel. (I assume it's a humbucker, since it's a 4-wire type)

 

[Verne Bunsen]

The middle pickup seems to be connected in parallel. (I assume it's a humbucker, since it's a 4-wire type)

This was my assessment as well. The diagram shows the middle HB in parallel whereas running just the black wire to the switch (with red and white joined) gives the HB in series. Strictly a user-preference thing, depending on the kind of sounds you're after.

As for the jumper on the switch, you are correct: it serves no purpose. Generally the jumper exists to electrically connect the two sides of the switch as they aren't connected internally, but since the other side of the switch isn't doing anything in this application that jumper is unneccessary. I would guess that the diagram was either modified from an existing diagram and that wasn't changed, or that it was drawn up by someone who wasn't sure exactly how the 5-Way switch worked and went with what was familiar.

 

[line6man]

The red and black wires indicate parallel wiring.

The jumper on the switch is a mistake that can increase the amount of popping noise that you hear when switching. This is not the first mistake that I have found in Seymour Duncan's diagrams. Sometimes they overcomplicate things.

 

[spauldingrules]

LOL yes - my way seemed so much simpler!  Thanks for the input!

 

[Jumble Jumble]

My recommendation with that set is to wire them all in series anyway. I've tried both ways and the volume difference is just too much.