Turning two J pickups into a humbucker!?

[gpcl16]

Why not design a pickup cover that will encase the two jazz pups together into a humbucker, side by side. I suppose you could grind the screw holder off of each side of a casing and then super glue them together.

That was exactly my original plan.

I guess I didn't word my original question very well. So just to clarify: Basically my original plan was to create a humbucker that is designed to have optimum single coil tone when split, but also have good tone when used in humbucking mode. This is in contrast to most humbuckers, which are designed to have optimum tone when they are used together in series and coil split tone is an afterthought.

So can I use two J bass bridge pickups and put one of them in backwards so that they cancel the hum when in series and fit together perfectly? Or will I need one bridge and one neck for the humcanceling? Basically my question is, is a j bass bridge pickup the same exact thing as a j bass neck pickup, just upside-down? Or is it also reverse wound? (I am also aware of the slight size difference.)

 

[wildhorse]

That was exactly my original plan.

I guess I didn't word my original question very well. So just to clarify: Basically my original plan was to create a humbucker that is designed to have optimum single coil tone when split, but also have good tone when used in humbucking mode. This is in contrast to most humbuckers, which are designed to have optimum tone when they are used together in series and coil split tone is an afterthought.

So can I use two J bass bridge pickups and put one of them in backwards so that they cancel the hum when in series and fit together perfectly? Or will I need one bridge and one neck for the humcanceling? Basically my question is, is a j bass bridge pickup the same exact thing as a j bass neck pickup, just upside-down? Or is it also reverse wound? (I am also aware of the slight size difference.)

Damn good question. I only know my neck and bridge hum cancel each other. Sorry

 

[allexcosta]

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[David Jayne]

Basically my question is, is a j bass bridge pickup the same exact thing as a j bass neck pickup, just upside-down?

Almost. Bridge pups typically have slightly more windings than neck pups. Aside from that you're correct. There's no such thing as 'reverse winding.' It's all about the magnets.

 

[gpcl16]

Cool, thanks for the info. I'll probably give creating this pickup a try, but it'll have to be after I get back from vacation in a few weeks.

 

[Stealth]

Sort of. They aren't 'counter wound'- the winding has nothing to do with it. It's the magnets that are reversed. North is up on one pickup, and South is up on the other. In addition, they are wired to the pots out of phase with each other, but the magnets, being opposite each other, 'fix' the signal so it's in phase at the jack. A P bass pickup works the same way- each half has it's magnets reversed compared to the other half. You can see this for yourself if you have a compass.

I'm surprised nobody chimed in on this yet.

Actually, on a regular jazz bass pickups are supposed to be counter-wound and counter-polarized. That way if you view the pickups from the top, one pickup is south-polarized and wound clockwise, while the other is north-polarized and wound counter-clockwise. Alternately, there could be a north-clockwise and a south-counterclockwise pair. Either way, the jazz bass pickups are supposed to be like that - a RWRP (reverse-wound, reverse-polarity) layout is optimal for hum-canceling. If you look at the P-pickup it should be the same.

As far as the jazzbucker? Definitely doable. Good luck with making it.

 

[gpcl16]

I'm surprised nobody chimed in on this yet.

Actually, on a regular jazz bass pickups are supposed to be counter-wound and counter-polarized. That way if you view the pickups from the top, one pickup is south-polarized and wound clockwise, while the other is north-polarized and wound counter-clockwise. Alternately, there could be a north-clockwise and a south-counterclockwise pair. Either way, the jazz bass pickups are supposed to be like that - a RWRP (reverse-wound, reverse-polarity) layout is optimal for hum-canceling. If you look at the P-pickup it should be the same.

Interesting. I've decided that I don't want to attach a bridge pickup to neck pickup, because of the slight size difference. So I guess that if I want ideal hum canceling, I should find two identical bridge pickups, except one is wound clockwise and placed north, and the other wound counter-clockwise and placed south. I guess this might be a good project to get a pickup winding kit and start making them myself.

And to the couple of people who said that they have done this before: I'd like to know how you ended up wiring it, and also what kind of results did you get from it.

Thanks for all the info everyone by the way. This is really helping me learn more about how a bass guitar really works.

 

[gpcl16]

There's no such thing as 'reverse winding.' It's all about the magnets.

There seems to be some disagreements about this. It seems that half of people say there is no such thing as reverse winding while others say there is. I don't really know who to believe.

I think we can agree that it's certainly possible to wind a pickup clockwise or counter-clockwise, but I guess the question is whether or not it matters. I'm leaning towards "it does matter" Certainly not nearly as much as the direction of the magnets, but I'm pretty sure it must have some effect. Anyone know for certain?

 

[Stealth]

Interesting. I've decided that I don't want to attach a bridge pickup to neck pickup, because of the slight size difference. So I guess that if I want ideal hum canceling, I should find two identical bridge pickups, except one is wound clockwise and placed north, and the other wound counter-clockwise and placed south. I guess this might be a good project to get a pickup winding kit and start making them myself.

Here's the thing: some generations of MIM (Made-in-Mexico) J-basses were produced with equal-length neck and bridge pickups. No idea whether they were RWRP, but a search around the basses and electronics forums might give you an answer. Using that or your own suggestion (finding two RWRP bridge coils) you should be able to make a humbucker of your choice.

And to the couple of people who said that they have done this before: I'd like to know how you ended up wiring it, and also what kind of results did you get from it.

Now here comes the Theoretician in me. So far I haven't made any pickups of my own, but there's two basic ways you can do it. Note that I'll be speaking in resistances here, where resistance can be roughly associated with how hot the pickups is.

Pickups in series get their resistances summed up:

Rtotal​ = R1​ + R2​

That way, two 7 kΩ coils in series (a reasonable assumption for a Jazz pickup) make a 14 kΩ humbucker - that's a fairly hot pickup (on par with Seymour Duncans).

Pickups in parallel yield the following resistance:

Rtotal​ = (R1​ × R2​) / (R1​ + R2​) which for equal coils (R1​ = R2​) gives you Rtotal​ = (R1​)/2

That way, two 7 kΩ coils in parallel would give you a 3.5 kΩ humbucker - fairly low-power, but could be usable. This is the reason why parallel pickups commonly have hotter-wound individual coils than series-ones. As far as how it sounds, here's an awesome quote:

Series: Highest output, warmest tone (bass and mid emphasis), hum-cancelling

Parellel: Lowest output, brightest tone (treble emphasis), hum-cancelling

Single coil: Slightly higher output than parallel, slightly less bright tone (though still noticeably brighter than series), not hum-cancelling on its own (might be if you combine it with other pu's)

Ideally, you should place the jazzbucker so the top coil is in the 60s position and the bottom coil is in the 70s position - that way if you decide to single the coil out, you can choose between the two sounds.

I think we can agree that it's certainly possible to wind a pickup clockwise or counter-clockwise, but I guess the question is whether or not it matters. I'm leaning towards "it does matter" Certainly not nearly as much as the direction of the magnets, but I'm pretty sure it must have some effect. Anyone know for certain?

It is indeed possible to wind a pickup differently. Suppose you take a long strip of cloth, extend your right arm so you can see it sideways and try to wind the strip around the hand so you're slowly moving from your fingers to your elbow. Then try to do the same with your left hand - it's obvious the winding is different. As far as whether it matters - it does. I can't really take the time to properly dissect the physics behind it, but suffice to say string movement passes through (with slight phasing occurring) while random noise picked up from the surroundings hits the pickups almost completely out of phase and cancels itself out.

 

[throbgod13]

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one coil is reverse wound..

 

[ugly_bassplayer]

Any sound clips of the JJ PU's??

 

[gpcl16]

Cool, thanks a lot for the info Stealth. I'll have to study up on the Physics of this. My physics is a little rusty since high school.

 

[thedreaded6]

so if you were to combine two jazz pickups to make a splittable humbucker, you could essentially glue together two MIM-type pickups, since they are equal length and would be RWRP? would you encounter problems since the bridge pickups are apparrently wound for higher output?

you could then wire the pickup to a switch for -bottom coil/series/top coil- could you not? that way you could get a 60s and 70s jazz as well as a humbucker.

I am sure you could find an aftermarket pickup manufacturer who produces MIM sized jazz pickups, though i can't think of any specific ones offhand. Can anyone think of any?

If I am not mistaken, the difference in length for MIA pickups between the neck and bridge is only 1/8", which is pretty negligable anyways, so the pole should line up well enough. Therefore i am sure you could just glue a set of jazz pickups together - correct me if i am wrong :S

 

[line6man]

I haven't read through the whole thread, but were you looking for a pickup like my Curtis Novak?

 

[thedreaded6]

YES. precisely. that appears to be RWRP right? and both bridge-length pickup sized. however, are those pickups only wired in series? or is a pickup like that splittable?

 

[David Jayne]

Almost. Bridge pups typically have slightly more windings than neck pups. Aside from that you're correct. There's no such thing as 'reverse winding.' It's all about the magnets.

EDIT: my bad. I have since learned about reverse winding. I does in fact exist.

 

[thedreaded6]

yes, i see. that curtis novak pickup looks exactly like what i am looking for.

but can it be hooked up to a bottom coil/series/top coil switch? or does it not have a way to wire it like that?

 

[line6man]

YES. precisely. that appears to be RWRP right? and both bridge-length pickup sized. however, are those pickups only wired in series? or is a pickup like that splittable?

Yes, it's certainly splittable.
My intention was to have a regular Jazz bass bridge pickup that would also give me a humbucker tone.

The way it works is there is a regular full-sized Jazz bass pickup, with a coil tap halfway through the winding, and then there is a half-wound Jazz coil.

In single coil mode, I use the full winding of the full-sized coil.
In humbucker mode, I run the tapped portion of the full-sized coil in series with the half-sized coil.

The reason for the coil tap and half-wound coil is to keep the output levels in check when switching between modes.
Just wiring two Jazz pickups in series greatly increases the output, so I had to compensate by using two weaker coils in series to add up to the same output as the single coil mode.

 

[thedreaded6]

oh i see, would it be possible then to a have pickup like that, but with two regular, full wound jazz pickups, but have the humbucker mode work in parallel instead of series, keeping the output level the same?

 

[bassbenj]

Almost. Bridge pups typically have slightly more windings than neck pups. Aside from that you're correct. There's no such thing as 'reverse winding.' It's all about the magnets.

This is not correct. There IS such a thing as "reverse winding" and it (or it's equivalent) is necessary to achieve humbucking action.

When you have a coil of wire it picks up a magnetic hum field. If you have a second coil the same size with the same number of turns it also picks up the hum field. If you wire the coils in series and flip one of the coils over, the hum voltage induced in the first coil exactly cancels the hum voltage induced in the second. Instead of flipping the coil over you could just reverse the leads. There is however a problem with this in that it reverses the wire that goes to the inside of the coil with the one that goes to the windings on the outside of it. Because there is a capacitance between the pole pieces, and other metal you may want to keep both coils with the "low" side (center of the coil) wired a certain way. Hence flipping the coil (or winding in the opposite direction which is the same thing) keeps the low side of both near the center.

But flipping the coil ALSO reverses the phase of the signal coming from the strings! Then, as you need to keep the string signal in phase, as dmusic 148 notes, the magnets in ONE coil are reversed. Now the string signals are IN phase but the hum signals are OUT of phase and cancel. That is the theory of a humbucker.

With jazz pickups this means that you need a bridge and neck pickup as a pair. One is reversed from the other to cancel hum. In SOME basses they are also different sizes as well, but the coils are adjusted so in spite of size differences they still exactly cancel hum. Other jazz pickups come in identical pairs. Most pickup makers offer both types for replacement in various basses.

But then you talked about EACH jazz pickup being a humbucker. In such a case you really don't need to worry about pairs because EACH half of your pickup is canceling hum. This is done much like we discussed above except that two coils are used in a single jazz pickup. Sometimes these are stacked vertically (known as stacked humbuckers) and sometimes the coils are side by side like a P bass but not offset. With noiseless pickups you want them all to be of the same type so string signals will be in phase.

If you'd like to experiment along these lines, I'd urge you to get a pair of Fender "noiseless" jazz pickups. These will have excellent single coil tone with no hum when used alone or in pairs. Stacked humbuckers in my experience tend to have a nasty "humbucker" tone to them compared to standard single coils. A pair of Jazz (noiseless) Pickups at the bridge (especially if you can control the volume of each) will give a very music man stingray tone to a bass. (especially with a hot active preamp with lots of boost and cut range). Half of that dual setup combined with neck noiseless jazz pickup will give a jazz bass type tone. Put the bridge and neck single pickups in series and you'll get a kind of P-bass like tone. Yes this is worthy of some experimenting.

The advantage of using "noiseless" (or equivalent) pickups is that since they are individually hum cancelling. You don't need to worry about matching one type with the opposite type when creating combos to make sure hum is cancelled. OK?

Good luck.