Humbucker and Phase Relationships

[MattSA]

I have found contradictory information on phase relations. I'm under the impression that the standard phase relationship for pickups is in-phase (out-of-phase produces "unwanted" or less usable tones) and that in-phase requires adjacent coils to be opposite polarity. It seems that all the humbuckers I have dealt with have one coil's polarity North and the second coil's polarity South, resulting in an in-phase relationship. Since the guitar I'm working on has two humbuckers, standard in-phase wiring requires that the neck humbucker's bottom coil be South and the bridge humbucker's top coil be North, or vice-versa, to produce an in-phase relationship between the two humbuckers. Is this correct?

Thanks,
MattSA

 

[hermetico]

Re: Humbucker and Phase Relationships

Well, despite of the fact that in-phase and out-of-phase really mean, same or oposite polarity...
Making it short, two coils, to be hum cancelling must have oposite MAGnetic polarity (Reverse Polarity) and oposite ELECtrical polarity (Reverse Wound).

Be aware that some of the schemes or information you will find in Internet are just calling North to the upper coil and South to the lower coil and, sometimes its not related to the Magnetic polarity but, simply as a (wrong) way to identify the two different coils.
I prefer to name them inner (closer to the center of guitar's body) and outer coils (away from the center of guitar's body).

Usually, makers do bridge and neck pickups with same polarity for each coil type (inner = usually slug coils; outer = usually screw coils). This is the case of SD (except for some models, like the P-Rails) so, when you want to combine two coils of two different humbuckers, you need one inner and one outer to have hum cancelling.
But there are other makers that reverse the polarity so, when you choose both inner or both outer coils, they are hum cancelling (what is usually named: they are in-phase). Even, P-Rails work in that way so, when you choose the two rails (inners) or the two P90 (outers) they are both in-phase.

So the answer to your question is barely yes, but it will finally depend on the maker and specific model!.

 

[uOpt]

Re: Humbucker and Phase Relationships

I have found contradictory information on phase relations. I'm under the impression that the standard phase relationship for pickups is in-phase (out-of-phase produces "unwanted" or less usable tones) and that in-phase requires adjacent coils to be opposite polarity. It seems that all the humbuckers I have dealt with have one coil's polarity North and the second coil's polarity South, resulting in an in-phase relationship. Since the guitar I'm working on has two humbuckers, standard in-phase wiring requires that the neck humbucker's bottom coil be South and the bridge humbucker's top coil be North, or vice-versa, to produce an in-phase relationship between the two humbuckers. Is this correct?


Thanks,
MattSA

If I understand the question correctly the answer is "doesn't matter". You can turn around the neck pickup (screws toward fretboard or slugs toward fretboard) without changing it's phase relative to the bridge pickup when both are on.

If you were to flip the magnet so that the other coil is north then you would be out-of-phase (regardless of how you mount it), until you also change the wires (if possible, with braided wire it's not).

 

[MattSA]

Re: Humbucker and Phase Relationships

First off, Im working with Seymour Duncan Pickups - a 59NL SH-1 '59 in the neck position and a TB11L Custom Custom in the bridge position.
To use the terminology introduced above:

The inner coils both have south magnetic polarity.
The outer coils both have north magnetic polarity.

From my understanding of phase relations, humbuckers are in-phase because one coil is magnetic north and the other coil is magnetic south.
Do the two humbuckers also need to be in-phase? In the situation I'm thinking about, the "inner" coils should also have opposite magnetic polarity, correct?

MattSA

 

[uOpt]

Re: Humbucker and Phase Relationships

You seem to ignore what people posted. You can turn the pickup around without getting into phase issues.

 

[G0lden]

Re: Humbucker and Phase Relationships

Don't just look at the magnets. Look at how each coil is wound. One must be wound one way, and the other the opposite. That way they make the same electrical "phase" (due to flipped magnetic polarity).

Like it has been said before, you can rotate a pickup all you want. Slugs toward the neck; slugs toward the bridge; it doesn't matter.

If you have never taken the 2 SD pickups apart, and they are still in stock condition, you will not have any phase issues. SD makes sure of that.

SD pickups are all wound so that the slugs have one magnetic pole and the screws have the opposite pole. That way you can take a neck pickup, flip it 180 degrees and throw it in the bridge position. You will still be in phase with another SD neck pickup.

So yes, in your case, the inner coils should have the same poles and the outer coils should have the same poles.

Make sense?

 

[robrob2]

Re: Humbucker and Phase Relationships

Things can get interesting when you split the two humbuckers and want hum canceling when you pair the single bridge with the single neck. As said above you must have magnetic and electrical phasing correct to get hum canceling. You need one coil North up and the other South up. You need one coil with clockwise current flow and one with counter-clockwise current flow (wind direction is really a misnomer).

You reverse the magnetic polarity by flipping a humbucker's magnet. You can reverse the current flow by reversing the humbuckers' coils' leads (for SD humbuckers: reverse the white and black; and reverse the red and green). Get the magnetic polarity wrong and you simply lose hum canceling. Get the electrical phase wrong and the split coil combo will sound hollow and weak.

 

[hermetico]

Re: Humbucker and Phase Relationships

Things can get interesting when you split the two humbuckers and want hum canceling when you pair the single bridge with the single neck. As said above you must have magnetic and electrical phasing correct to get hum canceling. You need one coil North up and the other South up. You need one coil with clockwise current flow and one with counter-clockwise current flow (wind direction is really a misnomer).

You reverse the magnetic polarity by flipping a humbucker's magnet. You can reverse the current flow by reversing the humbuckers' coils' leads (for SD humbuckers: reverse the white and black; and reverse the red and green). Get the magnetic polarity wrong and you simply lose hum canceling. Get the electrical phase wrong and the split coil combo will sound hollow and weak.

^^^^
+1

 

[robrob2]

Re: Humbucker and Phase Relationships

When working with a guitar with two humbuckers (HH) you need to start with getting the electrical phase correct between them when all 4 coils are active (no coil split on either humbucker). If both humbuckers are from the same manufacturer then both would be wired normally (SD black hot, green ground).

When out of phase the combined outputs sound hollow, nasaly and weaker than when in phase. You change the electrical phase of the whole humbucker by swapping its hot out and ground. Magnetic polarity of the two humbuckers when all 4 coils are active doesn't matter (it also doesn't matter when combining a humbucker with both coils active with a single coil pickup).

Normal magnetic polarity for a pair of humbuckers is SN....NS

Once you have the electrical phase correct for the two humbuckers with all 4 coils active you can work on getting the electrical and magnetic phase correct for them when they are combined and both have one coil split. You normally want the bridge humbucker to have its inside (neck side) coil active when split because it will sense more string movement. With SD humbuckers the inside coil is usually North and its wires are black and white. There are exceptions to this general rule. My SD Invader humbucker's inside coil is South when the "Seymour Duncan" logo is correct. I highly recommend you purchase a $9 magnetic polarity tester from StewMac to verify your polarity.

With SN....NS polarity and using the inside coil the bridge polarity would be North. You would then need to have the neck pickup's South coil active when split. With SD wiring the South coil's wires are red and green (active) and the North wires are black and white (both grounded when split).

 

[MattSA]

Re: Humbucker and Phase Relationships

I understand that in order for the humbuckers to be hum resistant their single-coils must be in phase. Now, I have two humbuckers in-phase. From what I read above, if I was to wire both humbuckers to a three way switch, obviously the neck and bridge humbuckers alone sound fine. What happens when both humbukers are active (when the switch is in its middle position)? Above, it says I may rotate the neck humbucker without worry of creating out-of-phase sounds when both humbuckers are active. This means the two humbuckers do not have to follow the adjacent rule for magnetic polarity (they should be opposite) because the single-coils are already canceling any hum for each of the humbuckers?

 

[robrob2]

Re: Humbucker and Phase Relationships

When pickups are magnetically and electrically in phase spinning them around 180 degrees (either one or both) will have no effect on phase or hum canceling.

 

[uOpt]

Re: Humbucker and Phase Relationships

I understand that in order for the humbuckers to be hum resistant their single-coils must be in phase. Now, I have two humbuckers in-phase. From what I read above, if I was to wire both humbuckers to a three way switch, obviously the neck and bridge humbuckers alone sound fine. What happens when both humbukers are active (when the switch is in its middle position)? Above, it says I may rotate the neck humbucker without worry of creating out-of-phase sounds when both humbuckers are active. This means the two humbuckers do not have to follow the adjacent rule for magnetic polarity (they should be opposite) because the single-coils are already canceling any hum for each of the humbuckers?

I think your confusion comes from that the magnetic field is really local to each pickup. One pickup cannot see what the magnetic field of the other pickup is oriented it (in significant quantities, for 2-pickup guitars at least).

 

[Artie]

Re: Humbucker and Phase Relationships

Making it short, two coils, to be hum cancelling must have oposite MAGnetic polarity (Reverse Polarity) and oposite ELECtrical polarity (Reverse Wound).

Don't just look at the magnets. Look at how each coil is wound. One must be wound one way, and the other the opposite.

As said above you must have magnetic and electrical phasing correct to get hum canceling. You need one coil North up and the other South up. You need one coil with clockwise current flow and one with counter-clockwise current flow (wind direction is really a misnomer).

Sorry guys, but these statements are all somewhat incorrect.
Magnetic polarity has nothing to do with hum-cancelling.
Both coils on a Duncan pickup are wound the same direction. They can be wound the same, or opposite, without regard for magnet polarity, and still be hum-cancelling. For example, both coils of a Duncan humbucker are wound the same direction, while the middle pickup in singles is wound reverse. When used with a neck or bridge pickup, its hum-cancelling.

Here's how it works: for hum-cancelling, we need two coils. If I wind them the same direction, I connect them start-finish-finish-start. If I wind the two coils opposite directions, I connect them start-finish-start-finish. Notice that both of those configurations are out-of-phase, internally, and hum-cancelling and I haven't brought magnets into the picture yet. (The start-finish-start-finish coils are out-of-phase because one is reverse wound.)

Now, for the signal to be in phase, I need the magnetic polarity of each coil to be opposite. In the first case, we get the typical humbucker, and in the second case we get the neck/middle or middle/bridge of single coils. (Or neck/bridge of a Tele.)

Does that make sense?

I'd post a diagram that might help, but I'm not at home.

 

[robrob2]

Re: Humbucker and Phase Relationships

Magnetic polarity has nothing to do with hum-cancelling.

It's silly to say magnetic polarity has nothing to do with hum-canceling when it's required for a functional hum canceling pickup.

 

[Artie]

Re: Humbucker and Phase Relationships

I meant that statement relative to understanding what the different aspects of pickup design do.
I can completely remove the magnet and a humbucker will remain silent. Swap the wires on one coil, (ie., start-finish-start-finish), and it will hum. The magnet is purely to produce the signal, and even its job is only to magnetize the strings. Remove the magnet and magnetize the strings and the pickup will continue to work fine, for awhile.

 

[uOpt]

Re: Humbucker and Phase Relationships

I would express it this way: messing with the magnetic polarity in a humbucker is only required to get things back in phase after you messed with the coil direction.

 

[Artie]

Re: Humbucker and Phase Relationships

:fing2:

 

[Fritz6]

Re: Humbucker and Phase Relationships

Hey November. The guy whose statement you called silly has helped alot of people, myself included, on this site with every kind of wiring problem imaginable over the years. He's a great guy and is THE go to maestro for all things electrical on this site. Instead of bustin his chops, try listening to him. You might learn something. He's forgotten more about this stuff than you think you know .

 

[MattSA]

Re: Humbucker and Phase Relationships

This is getting more technical then I think I require. I think at this point I'm just confused about having two humbuckers active at the same time. If both are wired correctly for in-phase relationship, and both are active via the middle position of a three way switch, your saying I should be fine. You also said I can rotate the bridge or neck pickup 180 degrees without causing problems. Are these statements correct?

Next, Im now concerned about electrical polarity. I understand this means knowing which interior lead is used as the ground and the hot lead. Switching the leads will also cause phase issues? Can you explain the science behind this? How does the electrical current affect polarity, scientifically? Also, what is the best way to test electrical polarity without opening the pickup? I have heard it can be determined with an ohmmeter but Im not sure how.

Thanks for all the help!
MattSA

 

[uOpt]

Re: Humbucker and Phase Relationships

Feeding the same signal but with phase reverted cancels the signal. In the case of two pickups being active it means that all the signal that is left is the part that was previously canceled out (when pickups were in phase).

There is no way to test wind direction without trying. Obviously if it's the same vendor then using the same colors will ensure that things are in phase.