Humbucking Tech Question

mudface

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This may be a dumb question,....

With the pair of coils of a humbucker would one coil being under wound or infact "Tapped" cause an impairment of the hum canceling?
 

strayedstrater

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Yes. How much depends on how different the coils are. With most asymmetric coils the extra noise is barely noticeable.

I'm not aware of any commercial humbucker with tapped coils, and having only one coil tapped would be even more unusual. The amount of extra noise would depend on how many winds the tap disconnects -- again the extra noise depends on how much different the two coils are.

If you actually meant "split" (turning off one coil), the noise cancelling goes away entirely.

Coil split vs coil tap:

The coils in a humbucker are normally connected in series. If you switch them to parallel the tone will be brighter, thinner, with less output, kinda sorta "single-coil"ish but will still be full humbucking. (Assuming the coils are matched -- asymmetric coils will have the same slight extra noise in both series and parallel).
 

mudface

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Yes. How much depends on how different the coils are. With most asymmetric coils the extra noise is barely noticeable.

I'm not aware of any commercial humbucker with tapped coils, and having only one coil tapped would be even more unusual. The amount of extra noise would depend on how many winds the tap disconnects -- again the extra noise depends on how much different the two coils are.

If you actually meant "split" (turning off one coil), the noise cancelling goes away entirely.

Coil split vs coil tap:

The coils in a humbucker are normally connected in series. If you switch them to parallel the tone will be brighter, thinner, with less output, kinda sorta "single-coil"ish but will still be full humbucking. (Assuming the coils are matched -- asymmetric coils will have the same slight extra noise in both series and parallel).
Yes,... i am aware there are no commercial pickups made with tapped pair of coils or single coil tapped pair of coils in a single humbucker pickup. (what a mouthful to say).

The thought i am having is if one of the coils could be tapped 50% or 25/75 what kind of change in tone would that have when paired with a full coil in a humbucker.

Will it have a frequency change that would be musically useful or would it simply be a weaker version of it's untapped tone?

The noise impairment would be the only drawback i would assume.
 

cooljuk

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...if one of the coils could be tapped 50% or 25/75 what kind of change in tone would that have when paired with a full coil in a humbucker.

Will it have a frequency change that would be musically useful or would it simply be a weaker version of it's untapped tone?

The noise impairment would be the only drawback i would assume.
Depends on the humbucker. Congested and dark humbuckers with strong magnets will have much less of a perceived difference than a clear and detailed pickup with a weaker magnet.


There's almost no reason to worry about hum, though. You can knock a single humbucker coil down to less than half of its partner coils turn counts and still have hum canceling. It may not be super perfect dead-on hum canceling, but NO humbucker is, because the two coils can't physically live in exactly the same space. If you hear a difference in a guitar rig, I'd be surprised.

I can say for certain, that I have a couple humbuckers out there with one coil underwound to an absolutely extreme amount of turn count offset from the other coil. This isn't a stock model of mine but sometimes this is just what's needed to balance out the sound of particular guitars.

There's a couple of these pickups I've built that hit stages 250+ nights a year in front of thousands (no exaggeration). I can tune in live and listen to them streaming on basically any given night, through a truly amazing rig. They sound great! The act I'm thinking of uses quite an elaborate lighting and power setup and there's still no perceived hum in humbucker mode, regardless of the severe turn count coil offset.
 

mudface

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Depends on the humbucker. Congested and dark humbuckers with strong magnets will have much less of a perceived difference than a clear and detailed pickup with a weaker magnet.


There's almost no reason to worry about hum, though. You can knock a single humbucker coil down to less than half of its partner coils turn counts and still have hum canceling. It may not be super perfect dead-on hum canceling, but NO humbucker is, because the two coils can't physically live in exactly the same space. If you hear a difference in a guitar rig, I'd be surprised.

I can say for certain, that I have a couple humbuckers out there with one coil underwound to an absolutely extreme amount of turn count offset from the other coil. This isn't a stock model of mine but sometimes this is just what's needed to balance out the sound of particular guitars.

There's a couple of these pickups I've built that hit stages 250+ nights a year in front of thousands (no exaggeration). I can tune in live and listen to them streaming on basically any given night, through a truly amazing rig. They sound great! The act I'm thinking of uses quite an elaborate lighting and power setup and there's still no perceived hum in humbucker mode, regardless of the severe turn count coil offset.
That’s very cool information,.... I had imagined that there was a use for this offset humbucker pair.

Would there be a useable tone change to have a switchable “tapped” coil in a humbucker?.....
 

cooljuk

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Though it's case-by-case what the exact result will be in various different humbucker designs, you could sort of quantify it like this....

If you have a given humbucker that has four conductor and you compare the sound of just the screw coil to full humbucker mode, then you cut the slug coil in half, you could roughly say the half-slug-coil-humbucker-mode would be halfway in between the full and split modes, but leaning more towards the humbucker side.

Man - that's crude figuring, though. Not really easy to quantify a thing like that until you do it in your pickup / guitar / rig!
 

cooljuk

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Would there be a useable tone change to have a switchable “tapped” coil in a humbucker?.....

I use it more as a problem solver than a tonal option in a single guitar but, yes, you could. It won't be as extreme of a difference in sound than say switching the two coils from series to parallel or just shorting one out entirely.

If you're going to do it, I'd suggest you tap 75% through the coil, as a starting point. Then, you can use the inside 75% or the outside 25%. Even if you did 50/50, the inside / outside would sound different from each other. You can also get wild and wind in such a way that you do upper / lower, rather than inside / outside. Feeling crazy? Wind 50% of the coil as a hurricane shape and the outside 50% as an upside down hurricane shape. Then, you have an upper-inside (bright) / lower-outside (warm) selection.

...but it's not a vintage PAF with L marks on the feet, so nobody would want it. lol!
 
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mudface

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I use it more as a problem solver than a tonal option in a single guitar but, yes, you could. It won't be as extreme of a difference in sound than say switching the two coils from series to parallel or just shorting one out entirely.

If you're going to do it, I'd suggest you tap 75% through the coil, as a starting point. Then, you can use the inside 75% or the outside 25%. Even if you did 50/50, the inside / outside would sound different from each other. You can also get wild and wind in such a way that you do upper / lower, rather than inside / outside. Feeling crazy? Wind 50% of the coil as a hurricane shape and the outside 50% as an upside down hurricane shape. Then, you have an upper-inside (bright) / lower-outside (warm) selection.

...but it's not a vintage PAF with L marks on the feet, so nobody would want it. lol!
Thank you very much..... this has been a curiosity of mine for awhile..... i may have to Frankenstein some cheap pups and work my way up to a PAF......lol!..... just kidding. But a 490 would be a good start. ;)

Have half the pickup stock and experiment with some hand wound bobbins tapped at different percentages and wire type.... and search for a sweet spot.
 
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cooljuk

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...But a 490 would be a good start. ;)
That's a prime example of a pickup that you will get the least result from. Those are very much one-trick-ponys. They always sound like themselves, with a pretty narrow range or voicing and dynamics.

If you want to play with something cheap, try a Yamaha pickup from an Artcore. Particularly, the ceramic or A3 versions. They are pretty clean. I'm not familiar enough with them to know what's what in what models but I know they can be among the clearest cheap pickups I've ever heard.
 

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This may be a dumb question,....

With the pair of coils of a humbucker would one coil being under wound or infact "Tapped" cause an impairment of the hum canceling?

Rather than tap one of the coils, you could do something a lot easier, and get a similar result, which is split the humbucker with a resistor. Normally if you split a humbucker, you go from the connection between the two coils to ground, and that grounds one one whole coil leaving you with one single coil. If instead of going straight to ground, you put a resistor in series with that path to ground, and in a sense you're keeping one coil fully active, and just turning the volume down on the other coil, which ends up sounding somwhere in between full series and split to a single coil. If you were to tap one of the coils and keep it in series as you're describing, I think the end result would be pretty similar to splitting with a resistor. Both methods will reduce the degree of hum cancelling.

The trick is figuring out the right resistance value, just as the trick with tapping would be to know where to put the tap point, so I'd suggest using a 20k trim pot, and then adjusting the resistance to be 10k, right in the middle, and then add or remove resistance to get the sound you like the best. Some people even dedicate a potentiometer so you can vary the resistance with a knob, and that has been referred to as a "spin a split" mod https://www.seymourduncan.com/blog/latest-updates/guitar-wiring-explored-the-spin-a-split-mod
 

mudface

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Rather than tap one of the coils, you could do something a lot easier, and get a similar result, which is split the humbucker with a resistor. Normally if you split a humbucker, you go from the connection between the two coils to ground, and that grounds one one whole coil leaving you with one single coil. If instead of going straight to ground, you put a resistor in series with that path to ground, and in a sense you're keeping one coil fully active, and just turning the volume down on the other coil, which ends up sounding somwhere in between full series and split to a single coil. If you were to tap one of the coils and keep it in series as you're describing, I think the end result would be pretty similar to splitting with a resistor. Both methods will reduce the degree of hum cancelling.

The trick is figuring out the right resistance value, just as the trick with tapping would be to know where to put the tap point, so I'd suggest using a 20k trim pot, and then adjusting the resistance to be 10k, right in the middle, and then add or remove resistance to get the sound you like the best. Some people even dedicate a potentiometer so you can vary the resistance with a knob, and that has been referred to as a "spin a split" mod https://www.seymourduncan.com/blog/latest-updates/guitar-wiring-explored-the-spin-a-split-mod
This seems like something to explore too..... awesome information thank you for your post!
 

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