Hum-Free Single Coil Neck + Dual Single Coil Bridge Pickup Operation

[5StringPocket]

This type of configuration is common in a J/MM with split-coil pickups which are hum-cancelling. The problem is, you don’t get the same classic jazz bass tone with a split coil neck pickup and one coil from a MM bridge pickup as you do from a pair of single coil pickups. I wanted to put this out there to make sure I understand this proposed design correctly.

You could use this idea with any pickup vendor but for this example I’m going to specify a Nordstrand Big Single neck pickup and a BigMan bridge pickup which has two single coils with opposite polarity so they are hum-cancelling when run together.
If the neck and bridge pickups were mounted so that the two most distant coils were in the 70’s jazz position, then a pair of switches could be installed to provide 70’s jazz, 60’s jazz, and both bridge coils together. In order to be hum-cancelling, 2 of the 3 coils have to be online with opposite polarity, with the 3rd coil isolated from the circuit.

The bridge pickup switch would be On/On/On to select neckmost coil, bridge coil, or both.
https://cdn.shopify.com/s/files/1/1...parallel-single_3_way_switch.pdf?v=1651785525
The neck pickup switch would be On/Off/On to select normal polarity, off, or reverse polarity.
on off on dpdt wiring - Bing
If the neck pickup were wired N(North) and the bridge pickup coils were wired S(South)/N then the hum-cancelling alignments might look like this:
- 60’s Jazz: Neck switch, normal polarity. Bridge switch, neckmost coil (bridge coil off)
- 70’s Jazz: Neck switch, reverse polarity. Bridge switch, bridge coil (neckmost coil off)
- Bridge Parallel: Neck switch, Off. Bridge switch, both coils On.

Would there be a grounding issue with reverse polarity on the neck pickup?
Pickup Wiring Diagrams and Schematics

 

[sikamikanico]

If I’m following, I don’t think this would work. You need reverse wound and reverse polarity (RWRP) for hum-cancellation. Just switching polarity on the neck pickup for 70s jazz sound won’t work, I believe. I’d be happy to be wrong, I’m sure someone more knowledgeable can correct me

that said, the “60s” jazz setting won’t quite sound like 60s jazz, because the bridge coil would be way out of place in the MM shell, particularly with the wider big singles. Might sound cool anyway tho…

I wonder if you could squeeze 3 J coils in an MM shell. Bridge-most coil would be 70s J, middle coil would be 60s J, and neck coil would be…well, neither. If their magnetic polarity/orientation was NSS (neck to bridge) combined with a neck J pickup (N) you could do these humcancelling modes with pickups in relatively correct spots:
- 70s J: neck pickup (N) + 70s J (S)
- 60s J: neck pickup (N) + 60s J (S)
- quasi-MM wide aperture humbucker: bridge pickup only, neck coil (N) and bridge coil/70s J (S)
- modern narrow aperture humbucker: bridge pickup only, neck coil (N) and middle coil/60s J (S)

 

[ctmullins]

If I’m following, I don’t think this would work. You need reverse wound and reverse polarity (RWRP) for hum-cancellation. Just switching polarity on the neck pickup for 70s jazz sound won’t work, I believe. I’d be happy to be wrong, I’m sure someone more knowledgeable can correct me

You’re not wrong; you’re exactly right. Hum-cancelling requires both a reverse-wound coil and a reverse magnetic polarity. You can do the first easily with a switch, but not the second. Just flipping the coil results in a terrible thin dorky tone.

 

[5StringPocket]

Thanks, forgot about reverse-wound as well as reverse polarity. Maybe a 60's jazz/MM would sound good with this Delano Hybrid?
Delano Hybrid Series - Best Bass Gear

Maybe this Subray 5 would be a good bass to add a route for the single coil neck pickup and install this pickup set in?
Sterling By Music Man StingRay RAY5 Bass Guitar - Black