Hum free inner outer coil splits and series parallel cross pickup coil combinations

[vinnie1971]

Hi all.

Most of us are used to coil splitting.
Some of us are used to splitting to either the screw or slug coil.
Some of us are used to the principles of combining the inner coils ( usually slugs) or the outer coils ( usually the screws) for strat-like cluck in between sound or telecaster like spanky in between sound.

But here are some other considerations I’ve come up with in my experiments:

Hum free inner and outer coil splits:
By rotating the neck pickup, the outer coils are the neck slug and bridge screw coil; the inner coils are the neck screw coil and the bridge screw coil. So you can have your inner and outer coil splits, but when both pickups are selected- then it’s hum cancelling.

One humbucker split together with the other full humbucker- normally this is done in parallel as that’s the easiest way to combine but the net effect is a little disappointing as it results in quite a bit of volume drop. That’s because the split coil is in parallel with the humbucker yielding a net DCR less than the DCR of one coil of a humbucker.

So in my latest HH guitar, I have universal coil splitting which gives hum cancelling inner and outer coil splits ( when both pickups are selected). I’m using an on off on switch : inner coil splits, coil split off, outer coil splits.
Plus I have the ability to combine one humbucker with a split coil. But I’ve done it like this ( using a push pull which is used in conjunction with my coil split toggle):
1. Neck north coil in series with ( neck south coil in parallel with bridge south coil) which gives a beefy neck focused outer coil split sound due to my rotated neck pickup, with a bit of bridge to colour the tone
2: bridge north coil in series with ( bridge south coil in parallel with neck south coil) which gives a beefy bridge focused inner coil split sound ( again due to the rotated neck pickup) with a bit of neck to colour the tone.

Let’s look at some example DCR numbers to help illustrate what’s going on here.

Taking HH project which has super 70 clones ( the DCR is PAF like but using oversized roughcast alnico 8 magnets, the inductance is high and they split really well, like super distortions)

Symmetrical wind ( both coils are the same DCR in each humbucker) I’m rounding to the nearest decimal point:
Bridge: 8.2k
Neck: 7.6k
Together in parallel that’s 3.9k

Bridge split: 4.1k
Neck split: 3.8k
Together in parallel: 2k

Bridge in parallel with neck split: 3k

Bridge north coil in series with (bridge south coil in parallel with with neck south coil): 6k

It takes a bit more figuring out to do this but it’s well worth it. I’ll do a demo shortly ...

I’ve deliberately left out putting humbucker coils in parallel with themselves instead of coil splitting as I’m not so keen on them. Taking my bridge pickup that takes the DCR down to 2K And when you put both bridge and neck as parallel with themselves and each other, that’s 1k. For vintage wound humbuckers that’s not very useable unless you have oversized magnets to bolster the inductance like in a Gretsch Filtertron.

Sorry about my handrawn on the phone diagram

This guitar also has out of phase and bass cut. Bass cut is useful as it gets these humbuckers in a similar tonal ball park as P90s, with no hum!

EDIT
Here’s a demo

https://youtu.be/e2O-x3a5mrM
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[Artie]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

The "DCR = output voltage" is invalid when talking about parallel connections. Imagine two AA cells as the two coils. In series, they're 3-volts. Split, they're 1.5 volts. Parallel, they're still 1.5 volts. The slight volume drop we hear when going to parallel is because the two coils are each picking up a slightly different string node, so you get tiny harmonic cancellations. The drop should be barely noticeable.

 

[Mincer]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

I did a similar wiring (and got hum-free by flipping a magnet). I wrote a blog about it, too.

 

[vinnie1971]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

The "DCR = output voltage" is invalid when talking about parallel connections. Imagine two AA cells as the two coils. In series, they're 3-volts. Split, they're 1.5 volts. Parallel, they're still 1.5 volts. The slight volume drop we hear when going to parallel is because the two coils are each picking up a slightly different string node, so you get tiny harmonic cancellations. The drop should be barely noticeable.

Except it to my ear it is quite noticeable. I have a Les Paul that has inner coil split, outer coil split and I can also put each humbucker in parallel with itself. I rarely use the humbuckers in parallel mode because the volume drop is more than going down to one coil. The pickups are Dimarzio Super Distortion and PAF pro.

That’s why I did a bit more thinking on this project. They’re really good useable sounds too.


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[vinnie1971]

Hum free inner outer coil splits and series parallel cross pickup coil combinations

I did a similar wiring (and got hum-free by flipping a magnet). I wrote a blog about it, too.

Hi Mincer,

I’m curious, did that result in out of phase?

I do have out of phase on this guitar but I can’t test if it would be hum cancelling as when I do inner or outer coil splits I’m selecting hum cancelling pairs already.

EDIT

I’ve just read the blog and listened to the samples, I think I’m hearing an out of phase sound there.

I used to have coil splits in those very same pickups. They do split well.

Regards
Vinnie

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[Mincer]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

No, it isn't out of phase...it has some 'quack' in there, but it isn't a thin sound at all.

 

[vinnie1971]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

No, it isn't out of phase...it has some 'quack' in there, but it isn't a thin sound at all.

Yes, it’s clucky with quite a scooped nasal sound. Not thin though. Sounds good.


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[vinnie1971]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

No, it isn't out of phase...it has some 'quack' in there, but it isn't a thin sound at all.

I’ve done that once in an HSH strat when i wanted to get humbuckers to split to the outer coils and be hum cancelling with the middle single coil. The south coils were the same electrical and magnetic polarity as the middle pickup so I flipped the magnets and revered the wires on the single coil so it was RWRP to the screw coils.


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[vinnie1971]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

And a demo of said coil combos among all the other tricks this guitar has from a totally passive circuit!

https://youtu.be/e2O-x3a5mrM


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[Mincer]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

Very cool video- great tones! Thanks for sharing!

 

[vinnie1971]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

Very cool video- great tones! Thanks for sharing!

There’s another vid on the way - there are 6 out of phase tones - all quite different due to being able to select different coils either in series or parallel or a combination of both!


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[DavidRavenMoon]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

Rotating the pickup doesn’t matter, unless you just want the sensing coil in a different location.

To achieve hum cancellation and not have the two coils not sound out of phase they need to have opposite magnetic polarity. The two coils themselves need to be electrically out of phase.


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[vinnie1971]

Hum free inner outer coil splits and series parallel cross pickup coil combinations

Rotating the pickup doesn’t matter, unless you just want the sensing coil in a different location.

To achieve hum cancellation and not have the two coils not sound out of phase they need to have opposite magnetic polarity. The two coils themselves need to be electrically out of phase.


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Yes, that’s the point, so I can get hum free inner coils or hum free outer coils. I select the bridge slug coil together with the neck crew coil to get hum free inner splits and the neck slug coil with the bridge screw coil to get outer coil splits. So I select RWRP pairs.

I did think about flipping a magnet and swapping the hot and ground wires over but as my covers were already soldered on I decided I’d just rotate the pickup instead.

When I select inner splits I connect the bridge series link wires to ground and the neck series link to hot on my on off on switch. For outer coils it’s the other way around.


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[DavidRavenMoon]

Hum free inner outer coil splits and series parallel cross pickup coil combinations

Yes, that’s the point, so I can get hum free inner coils or hum free outer coils. I select the bridge slug coil together with the neck crew coil to get hum free inner splits and the neck slug coil with the bridge screw coil to get outer coil splits. So I select RWRP pairs.

I did think about flipping a magnet and swapping the hot and ground wires over but as my covers were already soldered on I decided I’d just rotate the pickup instead.

When I select inner splits I connect the bridge series link wires to ground and the neck series link to hot on my on off on switch. For outer coils it’s the other way around.


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My point was it doesn’t matter if it’s inner or outer coils. As long as you have a north and south.

You can do a screw and a slug coil. It wouldn’t sound that different.


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[vinnie1971]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

No, it isn't out of phase...it has some 'quack' in there, but it isn't a thin sound at all.

Hi Mincer.

My OCD got the better of me, I decided I didn’t like aesthetics so much so I have flipped the magnet, swapped the hot and ground over and put the pickup back to normal orientation, so now my bridge slug coil is north and my neck slug is south and still got him cancelling pairs.

It could be my ears but I think the screw coils sound a tad brighter so this does seem to enhance the difference slightly between inner and outer coil splits - especially when both pickups are selected.

So thanks for mentioning it. I should have done that in the first place - ( I was just lazy because I’d already soldered the covers on. Plus I put masking tape over the coils and a bead of rubbery glue then clamp the cover in place before I solder to stop squeal)


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[Mincer]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

I am happy it worked out. I have this setup in several guitars now.

 

[PFDarkside]

Re: Hum free inner outer coil splits and series parallel cross pickup coil combinatio

Hi Mincer.

My OCD got the better of me, I decided I didn’t like aesthetics so much so I have flipped the magnet, swapped the hot and ground over and put the pickup back to normal orientation, so now my bridge slug coil is north and my neck slug is south and still got him cancelling pairs.

It could be my ears but I think the screw coils sound a tad brighter so this does seem to enhance the difference slightly between inner and outer coil splits - especially when both pickups are selected.

So thanks for mentioning it. I should have done that in the first place - ( I was just lazy because I’d already soldered the covers on. Plus I put masking tape over the coils and a bead of rubbery glue then clamp the cover in place before I solder to stop squeal)


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This seems much more effective for tonal differences than a slug and screw vs a slug and screw.

I still need to try this...

 

[vinnie1971]

Hum free inner outer coil splits and series parallel cross pickup coil combinations

This seems much more effective for tonal differences than a slug and screw vs a slug and screw.

I still need to try this...

The next thing I’m trying is no push pulls, just a super switch with 2 humbuckers ( with neck rotated as this set are vacuum wax potted) to get :

1 bridge humbucker
2 bridge slug coil and neck screw coil in series ( giving an inner coils humbucker)
3 Both humbuckers
4 neck slug coil in series with neck and bridge screw coils which are together in parallel
5 neck humbucker.

I may experiment with a 3 position 4 pole rotary switch to see if I can swap the functionality of 2 and 4 over to get
Position 2 as bridge slug in series with bridge and neck screw coils which are together in parallel and
Position 4 as neck slug coil in series with bridge and screw coil for an outer coils humbucker for position 4

Then see what out of phase or other sounds can be achieved on the 3rd rotary switch.

The reason I’m not going for regular coil splitting is that this set of humbuckers are assymetric. The bridge is 8.5k with the screw coil being 4.5k, the neck is 8.2k with the screw coil being 4.2k, they’re alnico 2 and have lowish inductance so while splitting to the screw coil is acceptable, slug coil splits sound terrible.


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