humbucker bobbin wiring

[Marco Pancaldi]

Re-reading the old Brosnac bible (Guitar Electronics for Musicians) I found, in the introduction, the following statement:

"Humbuckers generally use one inside coil wire for the hot lead and the other inside coil wire for the ground lead. Humbucker pose a problem because the ground and hot lead need to came from the same location of each coil. It is felt that using the outside lead is not the best choice."

Can someone explain better? And is this correct even using "mirroring" (reverse wound) bobbins?

I was sure that with modern 4-conductor humbuckers it was possible to wire the PU in ANY configuration, for the phase and bobbin "order" (I mean, from HOT to COLD) to manage at best overall phasing and coil cut in a specific guitar without to risk tone changes or noisier behaviour...

many thanks
m.p.

[Spence]

Suck it and see for a definitive answer.........
There are good reasons to have the ground on the inside of a coil, mostly to do with noise. If you do that, because both coils of a humbucker are wound in the same direction, the hot lead from the second coil will also have to be the inside start wire.

[Tonerider]

Interesting point, but I cant hear or measure a shred of difference in noise whether the coil starts on the inside or the outside. With the standard configuration outlined in the first post, the second coil starts on the outside and ends on the inside. No noise issues.

The acid test would be a strat single coil...If you installed one and found it to out of phase and non-humcancelling and so reversed the wires, do you think more noise would be introduced? I cant hear it.

Humbucker noise (the slight residual noise in most buckers) is usually due to different loading of the coil. Screw poles and slug poles load the coil in different ways, and hence the interference does not occur in symmetry. Mojo, however, does seem to occur with the assymetrical Gibson design.

[Marco Pancaldi]

Some puzzles from my disturbed mind:

About SC:
the standard configuration (inside/start to ground - outside/end to hot) is safer in case of broken wire insulation on magnetic poles, but I suspect that if you use plastic bobbins or tape insulation on the poles you can use the inner end as hot, obtaining little more "auto-shielding" from the (now grounded) external layers.

I don't know if this "reversing" can give little more capacitance (similar to contouring the coil with grounded copper strips) and less lively high frequencies. Your experiences?

Little drawback: you have buzzing from touching the poles, so you need to ground the poles too (more capacitance?).


About HB:
I don't undertsand this: the main idea is "inside to ground = less noise", right?
But if, starting from the ground, I wire the first coil "inside to ground" (best for noise), I need to wire the second coil "inside to hot" (worst for noise), and viceversa. So the question now is: which coil needs the best (for the noise) polarity arrangement, the "to-ground" one or the "to-hot" one?

The apparent ideal solution should be using mirroring coils, using all insides in "to ground" direction and all outsides in "to hot" direction, independently from the coil order from ground to hot. But this implies that reversing the total PU polarity gives makes more (or less) noise.
I hope it is clear. Comments?

m.p.

[David Schwab]

Having the inside of the coil as ground is considered a good practice because the pole pieces are capacitively linked to the inside of the coil. In practice as long as your poles are grounded it shouldn't matter.

With ungrounded poles, as on a Fender pickup, you will probably get less noise with the inside of the coil as ground, especially if you touch the magnets. The magnets really should be grounded.

I've been winding my humbuckers with both coils in the same direction, and wiring one in reverse, but I might start winding one in reverse. I guess as long as the inside start wire on one coils is to ground, it wouldn't mater as much for the series coil, since it's not directly connected to ground...

In the end it's all pedantic!

[Spence]

Golden rule number 1:

If it ain't broke, don't fix it.

So by all means be curious about how these things work but the long and short of it is not to fuck around theorising, working out equations or arguing about things. Just get on and make a pickup like the industry standards. If you still think that's not good enough, then put your science hat on.

This is not criticism, it's what the Japanese did after the war years. Didn't do them any harm.

[SkinnyWire]

In humbuckers, the noise is canceled by the "bucking" currents induced in the coils by external RF impinging fields (such as overhead lighting, emanations from a CRT based television, etc.). That has nothing to do with inside start/outside start. As long as you follow the rules required to set up the bucking current, you'll cancel the noise folks are talking about. You can cause other noise issues with wiring, but ...

It's handy to draw a field diagram and use the right-hand-rule or some other method to "see" what's going on in and around the coils.

[David Schwab]

In humbuckers, the noise is canceled by the "bucking" currents induced in the coils by external RF impinging fields (such as overhead lighting, emanations from a CRT based television, etc.). That has nothing to do with inside start/outside start.

There's several different types of interference, and some of them are not bucked very well because their wavelength is too short. That's the high frequency buzz you hear. The low frequency stuff cancels just fine though. Good shielding gets the rest.

There's no reason to wind humbuckers CW/CCW unless your pole pieces are not grounded. Having the "hot" on the inside of the coil, touching the ungrounded poles will add noise. But (most) humbuckers are not made that way, so there's no need to worry.

Just to paint a clearer picture... the coils are wired out of phase, so any signal common to both coils will cancel out when the output of the two coils is summed together. The string's signal does not cancel out because of the opposite magnet polarity of each coil. The string is picked up in a differential manner, being out of phase with each coil, so when the two coils are summed, the resulting signal is in phase.

One of the reasons we lose some highs is those harmonics are closer together and get attenuated by the bucking effect.

[SkinnyWire]

There's several different types of interference, and some of them are not bucked very well because their wavelength is too short. That's the high frequency buzz you hear. The low frequency stuff cancels just fine though. Good shielding gets the rest.

There's no reason to wind humbuckers CW/CCW unless your pole pieces are not grounded. Having the "hot" on the inside of the coil, touching the ungrounded poles will add noise. But (most) humbuckers are not made that way, so there's no need to worry.

Just to paint a clearer picture... the coils are wired out of phase, so any signal common to both coils will cancel out when the output of the two coils is summed together. The string's signal does not cancel out because of the opposite magnet polarity of each coil. The string is picked up in a differential manner, being out of phase with each coil, so when the two coils are summed, the resulting signal is in phase.

One of the reasons we lose some highs is those harmonics are closer together and get attenuated by the bucking effect.

ok

[Stan H]

Just to paint a clearer picture... the coils are wired out of phase, so any signal common to both coils will cancel out when the output of the two coils is summed together. The string's signal does not cancel out because of the opposite magnet polarity of each coil. The string is picked up in a differential manner, being out of phase with each coil, so when the two coils are summed, the resulting signal is in phase.

One of the reasons we lose some highs is those harmonics are closer together and get attenuated by the bucking effect.

That's one of the easiest to understand explanations I ever heard. Thanks David!

-Stan