Modifying/manipulating one coil from a humbucker

[dNA]

I was wondering if it's possible to take an existing humbucking pickup and alter/modify only one of the two coils.

The reason I ask is because I have a dual humbucker guitar with a switch that gives me one coil from each in parallel in the center position. I really like the way it sounds with the current pickups. Conversely, I find the neck humbucker in standard series mode to be a bit too fat. I know that if I were to change this pickup out for a brighter humbucker, the center position would change and I don't want that to happen. This is generally the problem with series/parallel for me - the tonal change is always a little more extreme than I want it to be.

So I was thinking if the coil that is being used in the center position is left untouched, can I change the tonality of the humbucker by manipulating the other coil? Can some col wind be undone to lower the output and make it a little brighter? Mind you I don't really know anything about the construction of a pickup, and I'd have a tech/pro do whatever mod if I thought it was a good idea. I know some companies produce humbuckers with coils that are mismatched for different tonality, so i know it's not a structural impossibility.


so, yes.. thoughts?

 

[TroubledTreble]

In short.. Yes. If you change the coil that is not used in the center position, when used in series in say the neck position it will alter the tone. There is much debate about whether it was the slug or the screw side of a PAF that typically had the lower wind. The PAF is known to have slightly offset coils, usually by a hundred or so winds.

There is certainly no harm to the pickup other than the mod is not reversible. As long as you don't change any of the other parts, i.e. the metal parts or the magnet, the active coil will not be affected by reducing the winds in the inactive coil. Changing the metal parts and magnet will change the overall inductance and magnetic structure of the pickup and therefore the overall tone.

Reducing the winds will brighten it up a little. It would be best to do both bobbins but that is not an option here. Another option would be to swap out the one bobbin with a coil wound with a different gauge wire. The different gauge will do more to affect the overall tone. There are makers who used mismatched gauges as well. One other thought is to put a small air gap at the coil that you would like to affect. That will lower it's output a little and sweeten it slightly. So maybe a combo of alterations would do the trick for you.

Edit* by "air gap" I am referring to pulling the magnet very slightly away from either the slugs or screws so the magnet does not come in full contact with them.

 

[dNA]

awesomeness. Thanks Ken. I want you to know the only reason I didn't take this question straight to you is because I know you're busy and you've got lots of more important work to attend to than answering my silly questions.


anyone here ever done something like this before?

 

[drewfx]

You can also try "partially" splitting the HB by putting a resistor to ground between the 2 coils in HB mode. Depending on the resistor value, you can get sounds between full humbucking and just the split coil. I'd try a 15k resistor to start with - still too fat, go lower; too thin, go higher.

 

[TroubledTreble]

awesomeness. Thanks Ken. I want you to know the only reason I didn't take this question straight to you is because I know you're busy and you've got lots of more important work to attend to than answering my silly questions.

Thanks for the consideration. As you know I have been working on some new stuff. Besides, I think it's good to put this stuff out there. I'm sure your not the only one to wonder and there may be other answers to consider. Love this place for that!

No silly questions unless it involves being silly. :icon_jokercolor:

 

[dNA]

You can also try "partially" splitting the HB by putting a resistor to ground between the 2 coils in HB mode. Depending on the resistor value, you can get sounds between full humbucking and just the split coil. I'd try a 15k resistor to start with - still too fat, go lower; too thin, go higher.

you know where in the equation that means i need to wire it with a 4PDT switch?

 

[drewfx]

You can also try "partially" splitting the HB by putting a resistor to ground between the 2 coils in HB mode. Depending on the resistor value, you can get sounds between full humbucking and just the split coil. I'd try a 15k resistor to start with - still too fat, go lower; too thin, go higher.

you know where in the equation that means i need to wire it with a 4PDT switch?

Hard to say without knowing the way the existing wiring is.

 

[pabloman]

Throw a pot on it and dial in the amount of coil so to speak. There's a diagram on the Duncan site.

 

[stubhead]

There's a diagram on the Duncan site.

What's it called?
http://www.seymourduncan.com/support/wiring-diagrams/

I have often though that because of my preference for split/series/parallel HB pickups with volume & tone for each, I might as well just put a volume pot and phase switch on each of the four coils. Boggle thyself... :hello2:

 

[dNA]

I think I got this setup going:
http://dimarzio.com/sites/default/files/diagrams/2h1v1t_1ep1111_reversepolarityB.pdf

 

[dNA]

Throw a pot on it and dial in the amount of coil so to speak. There's a diagram on the Duncan site.

while a cool concept, I am not much for using knobs on the fly and I don't think i would find it practical to have that as a feature.

 

[pabloman]

It will allow you to change the amount of the second coil when going into humbler mode. You can dial in the tone and leave it there. Hell you could even use a trim pot in the cavity. Essentially the same thing as removing turns of wire on a pup. Yet its much less permanent and invasive.


The mod is called a spin a split. I've also heard it called dial a tap. It's in the FAQ section or tech tips I believe. Sorry I would post a link but I'm posting from my phone.

 

[stubhead]

http://www.seymourduncan.com/support/choosing-installing/tech-tips/spinasplit/

http://www.seymourduncan.com/support/schematics/schematics.php?schematic=sum96tip

Hmm. Hmmm. And with two HBs and two concentric pots, you'd be.... nuts as a bunny! A happy happy bunny.... :hello2:

 

[drewfx]

It will allow you to change the amount of the second coil when going into humbler mode. You can dial in the tone and leave it there. Hell you could even use a trim pot in the cavity.

I have to try to avoid using trim pots as I feel strangely compelled to open things with trim pots up and tweak them every so often - even if I've gone through this before and know they're already set "perfect".  :doh: :sad1:

So I find settling on a resistor and leaving it works better for me. YMMV.

 

[drewfx]

I think I got this setup going:
http://dimarzio.com/sites/default/files/diagrams/2h1v1t_1ep1111_reversepolarityB.pdf

In that diagram, look at the bottom "half" of the switch.

You have a row, left to right, that's labeled "neck (black and white)", a connection to ground in the middle and an unused lug on the right. If you put a resistor (or pot, or trim pot) between the "neck (black and white)" on the left and the unused lug on the right it will give you a "partial split" in the neck position.

Similar on the bottom row - put the resistor between the unused lug on the left and the "bridge red & green" lug on the right.

 

[stubhead]

How did you hit on the 15K resistor? I mean, is there some math behind it.... I know they're dirt cheap, but did Radio Shack have what you want? Singles of 10K-15K-20K-etc. When I read about "fixing" pots with a 750K resistor, I had to buy a hundred... might last a me a bit.

http://www.projectguitar.com/tut/potm.htm

 

[pabloman]

I am fortunate enough to live near a really cool electronics store. They sell small parts in 5 packs. Been wire by the foot. It's like a candy store.

 

[drewfx]

How did you hit on the 15K resistor? I mean, is there some math behind it.... I know they're dirt cheap, but did Radio Shack have what you want? Singles of 10K-15K-20K-etc. When I read about "fixing" pots with a 750K resistor, I had to buy a hundred... might last a me a bit.

http://www.projectguitar.com/tut/potm.htm

I just jumpered up different resistors when I was trying to get a decent single coil sound from splitting a low output HB (I found 7-8k sounded reasonable in that application). Based on that experience, it seems to me 15k would be a good starting point for taming a high output HB.

Of course, you could do the math if you wanted to calculate the DC resistance when you partially split the HB, but DC resistance in and of itself doesn't mean much, so I'd rather go by ear. But the calculation for the new DC resistance would be:

RC1 = DC resistance of coil 1 (primary coil connected to output)
RC2 = DC resistance of coil 2 (partially split coil)
R3 = resistance from resistor(s) you add going to ground between the coils

= RC1 + (RC2*R3)/(RC2+R3)

 

[dNA]

I have to try to avoid using trim pots as I feel strangely compelled to open things with trim pots up and tweak them every so often - even if I've gone through this before and know they're already set "perfect".   :doh: :sad1:

So I find settling on a resistor and leaving it works better for me. YMMV.

i absolutely feel you on this. If i know there's something that can be tweaked i will always want to tweak it. and with a rear-routed guitar that's almost too easy. But i might try it just because it seems like it would require less experimentation and soldering. i've gotten pretty good at soldering quickly and cleanly, but is till hate doing it.


thanks so much for the feedback guys. For what it's worth, these are DiMarzio 36th Anniversary PAFs - they're hotter than the old PAF classics (which i have in another guitar), but i think they still qualify as lower output, right? Maybe i should start with a lower value resistor?

 

[dNA]

I think I got this setup going:
http://dimarzio.com/sites/default/files/diagrams/2h1v1t_1ep1111_reversepolarityB.pdf

In that diagram, look at the bottom "half" of the switch.

You have a row, left to right, that's labeled "neck (black and white)", a connection to ground in the middle and an unused lug on the right. If you put a resistor (or pot, or trim pot) between the "neck (black and white)" on the left and the unused lug on the right it will give you a "partial split" in the neck position.

Similar on the bottom row - put the resistor between the unused lug on the left and the "bridge red & green" lug on the right.

Hey, I haven't tried this just yet. I was getting ready to, and then I thought about how i have an unused knob on this guitar (it's a vol/vol/tone layout originally, but this wiring only used vol/tone.) Could I actually wire a pot in place of the resistor you were referring to and have a level control for that one coil?
Could i also put a switch to switch a resistor in and out? And actually, did somebody suggest this already?


sorry if i'm seeming kind of tech-ignorant. I feel like i should understand how all this stuff works (i've studied a bit of electronics and i've always done my own soldering) but my brain just kinda shuts off when it comes to the details.