If you go to the PRS Guitars web site and look at the video for the 513 model (five pickups, 13 different sounds) you will see and hear a beautiful guitar that sounds awesome. It uses two dual-coil humbuckers at the neck and bridge, and a single-coil pickup in the middle. Apparently the PRS-513 switching system also treats the humbuckers as single-coil pickups.
If it used different switches, it could have 20 unique humbucking outputs from five single-coil pickups, taken in parallel and serial humbucking pairs. But the two humbuckers put their coils very close together, which might cause some of the outputs to have less tonal distinction. There are several general principles that apply to the tonal quality of humbucking pairs (all other things being equal):
- Pairs closer to the bridge are brighter than those closer to the neck
- Pairs closer together are brighter than those farther apart
- Parallel-connected pairs are weaker and brighter than series-connected pairs
- Counter-phase (out-of-phase) pairs are brighter and weaker than in-phase pairs
- Rules 1-4 can interfere with each other
- You can only put so many pickups between the neck and the bridge, and the more you have, the smaller the tonal differences in adjacent pairs with the same connections.