RWRP P-pickup Question

[radrobgray]

If I *don't* wind one P coil RWRP, but do one coil north, one coil south and wire it in series it should still be humbucking? I'm not grasping why its necessary to do RWRP on a P if we don't in a standard guitar humbucker.

[big_teee]

This is what is the established NORM for non RWRP, from other threadsl
http://music-electronics-forum.com/t38163/
Post 10.


"This is a quote from Jason Lollar, off a Mustang bass thread.
When it comes to two coils played together ,whether a double coil pickup or playing two single Coils together?

"Reverse Wound is What Cancels Hum, and Reverse Polarity is what sets the Phase."

[big_teee]

If I *don't* wind one P coil RWRP, but do one coil north, one coil south and wire it in series it should still be humbucking? I'm not grasping why its necessary to do RWRP on a P if we don't in a standard guitar humbucker.

To try to answer your question better?
On a regular 2 coil humbucker? Though they are both wound the same direction?
One coil has the input on the start, the other coil the input is on the finish.
See diagram.
http://www.1728.org/humbckr7.gif
You can also do that on a P pickup, by wiring the two finish, or two start leads together, and polarizing one magnet north, and one south.
That makes the coils reverse wound, & rev polarity, even though both coils are wound in the same direction.
It is not necessary to make one coil north up and one coil south up on a split pickup, for it to be hum canceling, (though typically they are wound, & wired RWRP).
Because each coil senses separate strings, on a P-bucker unlike a guitar humbuck that both coils sense all strings.
Noise issues are also to be considered with rod magnet single coils, and split rod humbuckers.
RW on one coil, is usually done to keep the input away from the magnets to help on static noise.
GL,
T
** If anyone else has any input to add on this, pleaes Jump In!

[Steve A.]

Having the hot lead next to the magnets in a strat pickup can introduce the possibility of it shorting out completely (I have seen many strat pickups with continuity between the windings and one of the studs.)

Steve A.

[David Schwab]

Having the hot lead next to the magnets in a strat pickup can introduce the possibility of it shorting out completely (I have seen many strat pickups with continuity between the windings and one of the studs.)

Steve A.

It also induces hum if you touch the magnets. That's why the Mustang had closed covers, since you could reverse the polarity of each pickup.

So the start should always be ground if you can help it.

[David Schwab]

"Reverse Wound is What Cancels Hum, and Reverse Polarity is what sets the Phase."

Reverse winding reverses the polarity. It's the reverse coil polarity and the reverse magnet polarity that cancels hum.

[big_teee]

I disagree!

On a P or mustang, you can have rod magnets same polarity or not.
The magnets set the phase.
Since each pickup senses separate strings, the phase doesn't matter.
The RW coils make it cancel hum.

[kayakerca]

The combinations of magnetic polarity of two coils and wind direction (relative to ground and hot) yields the same results as the chart below (from one of my books) in my experience. Magnetic polarity and wind direction work in conjunction with each other in my limited experience, but the physics doesn't change regardless of years of experience.

[big_teee]

The combinations of magnetic polarity of two coils and wind direction (relative to ground and hot) yields the same results as the chart below (from one of my books) in my experience. Magnetic polarity and wind direction work in conjunction with each other in my limited experience, but the physics doesn't change regardless of years of experience.

[ATTACH=CONFIG]47777[/ATTACH]

IME the diagram above applies where both coils sense the same strings.
That doesn't necessarily apply with a P bass, or mustang bass.
both bobbin coils sense separate strings, so the polarity is not a big issue, but RW is.
With a J-bass it would matter, cause both bobbins sense all strings.
Check out this thread, posts 16-22.
http://music-electronics-forum.com/t36630/
At that time I checked it, and it seemed to be that way.
See if you agree?
T
**DS won't agree, he never does!

[kayakerca]

IME the diagram above applies where both coils sense the same strings.
That doesn't necessarily apply with a P bass, or mustang bass.
both bobbin coils sense separate strings, so the polarity is not a big issue, but RW is.
With a J-bass it would matter, cause both bobbins sense all strings.
Check out this thread, posts 16-22.
http://music-electronics-forum.com/t36630/
At that time I checked it, and it seemed to be that way.
See if you agree?
T
**DS won't agree, he never does!

I've gone through the posts. It seems to be pretty much the same as in the phase chart from the book though. But the Jason Lollar comment below (from the referred threads) seems to read (when talking about the P-bass) that if the magnetic polarity is the same, then "humbucking" and "in phase" are mutually exclusive. That would be the same for a humbucker being address by the same string set.

I don’t know why Fender made the P bass alternating polarity, the vintage mustang bass and fender 12 both have coils with the same magnetic polarity and humcancel- they are out of phase with each other.

I've been winding my P-bass pickups just like a humbucker from both a magnetic polarity and wind direction perspective. They are definitely in phase and no one has complained about them not humbucking. I best sit down and think about this some more until it sinks in a little better than it is at this point.

[big_teee]

Post 16

no reason to make one north up and one south up if both bobbins dont sense the same string- thats only so both bobbins are in phase with each other but they dont need to be in order to hum cancel on a typical gibson style humbucker both bobbins have to be in phase but mustang bass, fender 12s and early Pbass were not made that way.

On a P, the coils don't have to be in magnetic phase, because each coil only senses 2 strings, the other coil senses the other two different strings.
If they are out of magnetic phase they still only sense two different strings, and they will work either way, and still cancel hum.
I tested it all at that time, It was Like Jason Lollar said, I don't have anything rigged up right now to test it again.
I may do the pickup test out of the guitar.
All I would have to do is re-magnetize one coil, so both coils are the same magnetic polarity, and see if it still cancels hum.
Right now I stand by my original statement.
T

**The important thing is for the pickup builder to be aware, and to adjust accordingly!

**++ An hour or two later, I just retested a loose set of P bass pickups.
RWRP they cancel hum and pass the pop test.
RWSP they still cancel hum and still pass the pop test. RWSP=Same polarity
To all, your test results are welcome! Those are mine.
I still stand by the J Lollar, and my original statement.

[kayakerca]

Post 16
I still stand by the J Lollar, and my original statement.

In the sincere desire by me to try and get a better handle on this, can you explain the advantage of building a P-bass as RWSP compared to RWRP, or just the disadvantage of building a RWRP pickup for a P-bass, or is there just going to be no difference whatsoever? For discussion sake, let's assume that from time to time there may be 2 strings plucked simultaneously, one from the 2 low strings and one from the 2 high, and, if or how this makes any difference to the analysis and conclusions.

[big_teee]

No real advantage, that I'm aware of.
I was trying to understand why the original Mustang was wired that way.
That was when JL chimed in.
As far as plucking multi-strings, it should make no difference because they are using different coils.
With one coil CW, the other CCW, and both same polarity magnets, your chart shows them to be out of phase.
The strings shouldn't care about phase polarity, and which way the signal is going because of the separate coils and separate strings.
Throw a J pickup in the mix, and not sure which would work best! Two strings in phase, two out of phase however you wire them.
As mowing season is cranking up again, I won't have much time to mess with the pickups.
If you do any experimenting, I'm interested in your test results.
That's my observations, that's it for me, and all I know about it.
So good luck to everyone.

T

[tbonuss]

Hello all, this is always a fascinating topic. I think you still need to reverse the polarity because there is overlap on the A and D strings.
Here's how I think about it:
You wire the pickup coils so they are hum canceling (the EMI noise doesn't care about the magnets, so you wire them so the noise coming from the coils is out of phase with each other).
Unless you want the pickups to to be signal cancelling, you then must reverse the polarity of the magnet so the two signals are in phase.
So noise out of phase, signal in phase.
If you don't reverse polarity of one of the pickups, the signals will be out of phase and "signal bucking". In this example, mostly on the A and D strings.

[Steve A.]

NWNP or RWRP... or NWRP or RWNP?!?

EDIT... Yikes, I forgot that a RWRP P Bass set will not work properly when used with a Jazz Bass pickup which is very common. I still suggest offering a RWRP set to someone who bends bass strings... let them decide.

EDIT2... A P Bass with a RWRP or RWNP set of pickups would have less hum than with a NWNP or NWRP set.

««●»»

Using the same polarity for both coils on split bass pickups as on a P bass can create problems if you were to bend strings by pulling on the A string or pushing on the D string.

Jason Lollar mentioned the Supro string-through pickup with each coil having the same magnetic polarity but it was intended for lap steel guitars where the 3rd and 4th strings are not usually pushed or pulled in a horizontal direction. Ry Cooder uses a Supro pickup in the bridge position of his Coodercaster but he plays a lot of slide guitar and he does have a Teisco gold foil pickup at the neck if he was going to bend strings with his fingers. Even with a lap steel it is kinda tricky to get the magnets for the 3rd and 4th strings adjusted right.

So I would suggest that split pickups for bass follow the same rules for polarity as PAF humbuckers since some bass players do bend strings like a guitarist (which was probably not that common when Leo came up with his designs in the 50s and early 60s):

https://www.talkbass.com/threads/guy...you-do.908695/

And as suggested earlier it is best not to use the start windings next to the magnets for the hot signal output as they can cause hum if you touch the magnets (you can reverse PAF humbucker coils because they are wound on a plastic bobbin.)

««●»»

The combinations of magnetic polarity of two coils and wind direction (relative to ground and hot) yields the same results as the chart below (from one of my books) in my experience. Magnetic polarity and wind direction work in conjunction with each other in my limited experience, but the physics doesn't change regardless of years of experience.

That chart is basically the same chart in the Donald Brosnac book provided to him by Seymour Duncan which led me to believe that an out-of-phase linkage could not be humcancelling which is not true. Yes, out of phase pickups can be humcancelling, a possibility I had ignored for 20 years in designing my custom wiring harnesses for strats and teles. Thanks a lot, Seymour!

Steve A.

EDIT... Yikes, I forgot that a RWRP P Bass set will not work properly when used with a Jazz Bass pickup which is a very common arrangement. My bad!