Curious about stacked humbuckers for jazz bass.

[shawnl]

I'm looking to replace a J style neck pickup for a bass but having some trouble trying to figure out how to wind a proper stacked humbucker. I know with dual coil humbuckers the practice is to use opposing magnetic polarities for each coil. However, with a stacked humbucker it would seem that both coils would have to share the same polepiece with the same magnetic polarity. I guess I'm trying to understand how hum-canceling can still be achieved this way. Can you have two coils both wound in the same direction or are you forced to have reverse winding on one of the coils?

Secondly, if the top coil is the one actually doing the string sensing does this make the bottom coil more of a dummy? Do the same series or parallel wiring schemes apply if only one coil is directly sensing for tone? For instance consider this configuration: I want an overall output of 10k. I'm going to wire in series to keep the size of each coil down so it will all fit inside J style cover. So each coil would be wound to 5k. However, if the top coil is really the only one sensing the strings and the bottom one is just there to cancel the hum, would I really be getting a full 10k worth of output because the two coils aren't performing the same equal way like they would in a soapbar or PAF? Is this why some people complain they are lower output than normal humbuckers?

[big_teee]

I'm looking to replace a J style neck pickup for a bass but having some trouble trying to figure out how to wind a proper stacked humbucker. I know with dual coil humbuckers the practice is to use opposing magnetic polarities for each coil. However, with a stacked humbucker it would seem that both coils would have to share the same polepiece with the same magnetic polarity. I guess I'm trying to understand how hum-canceling can still be achieved this way. Can you have two coils both wound in the same direction or are you forced to have reverse winding on one of the coils?

Secondly, if the top coil is the one actually doing the string sensing does this make the bottom coil more of a dummy? Do the same series or parallel wiring schemes apply if only one coil is directly sensing for tone? For instance consider this configuration: I want an overall output of 10k. I'm going to wire in series to keep the size of each coil down so it will all fit inside J style cover. So each coil would be wound to 5k. However, if the top coil is really the only one sensing the strings and the bottom one is just there to cancel the hum, would I really be getting a full 10k worth of output because the two coils aren't performing the same equal way like they would in a soapbar or PAF? Is this why some people complain they are lower output than normal humbuckers?

Not to hi-jack your stacked post, but Mojo has ready made flatwork for the buzz-kill.
2 bobbins side by side.
You can buy both neck and bridge versions.
Looks like it fits in the standard Jazz covers.

Mojotone Hum Cancelling Jazz Bass Bridge Flatwork Top and Bottom Set (for .187'' dia. magnets)

[David Schwab]

You can also use standard Jazz flatwork for a stack; just stick an extra piece in the middle.

Stacked pickups have the two coils out of phase. Because of that they tend to be thin sounding. So you will notice that they are wound hot to make up for it. If you want a bright pickup, then stacks work great.

The side by side humbuckers are probably easier to make, as long as you have the parts, and require less wire wound on them. They don't work as well for odd numbered strings though, like on a 5 string. They will hum cancel fine, but each half tends to sound a little different.

[shawnl]

I think I might be better off with a split coil if I want the hum-cancelling aspects in a J style space.