Stacked Single Coil Sized Humbucker

[nickc35]

Has anyone built a single-coil sized stacked humbucker for a Strat type guitar? I have a friend who wants me to make one for him but I don't know how they're made. Does it require special bobbins? Are there parts available out there to make them?

Any help would be greatly appreciated.

[Mark Hammer]

The simplest thing is to use the tallest polepieces (i.e., the ones normally used for the G and D strings with staggered polepieces), and stick a second piece of flatwork halfway up the polepiece, winding one coil for the top, and the second on the bottom. Wire them up appropriately, and there you go.

Some 25 years ago, I was told by the guy who made the Evans pickups that he could not get such stacked bumbuckers to sound good. His own design was a side-by-side dual coil, that fiut yin-yang style in a Strat-sized cover, not unlike the current Fralin units. I was never really partial to the Evans, but then I mostly heard them played by guys using Tube Screamers, so I may not have heard the raw tone of them. Bottom line is that his comments may have reflected some fairly specific tonal goals that not all of us share, OR they may have been realistic and wise. I don't know. What I do know is that I made a couple, using Gibson bobbins, and they were dead quiet and sounded okay. But I haven't heard them in so long, I wouldn't consider that a valid opinion.

[David Schwab]

I made a stacked Tele bridge pickup, and I've installed a lot of the commercial stacks. They actually do a good job when you want clean and bright, as they tend to not have a lot of bottom end unless you wind them really hot, like to 25k.

If you want standard Strat type tones, like 8,000 turns per coil and work up from there.

[nickc35]

So there is only one magnet polarity facing the strings....unlike a standard side-by-side humbucker where one coil is south and the other north?

Do I wire the two coils the same way a standard humbucker is wired, finish wire to finish wire if they're both wound in the same direction or finish of one to start of another if they're wound in opposite directions?

David - Won't it be on the hot side if have 8000 turns per coil? I'm thinking I don't want a real hot pickup but maybe the design requires higher dc resistance to sound good? I don't know, just asking.

Thanks for the help!

[Mark Hammer]

In a sense, there is only one "magnet" in a PAF-style humbucker as well. It just happens to be U-shaped, with some "fingers" that extend out of the magnet at each end and take a sharp 90-degree turn. We think of the two coils as if they lived in separate magnetic universes, but really, it's just one coil at the southy end of the magnet and another at the northy end of the same magnet. When one makes a stacked humbucker, all you're really doing is "straightening out the magnet".

Take a peek at the thread in the main pickup-makers forum regarding the pickup for the Gibson Ripper bass ( http://music-electronics-forum.com/t29924/ ), and you'll see a different version. In this case, it is essentially a stacked humbucker sitting on its side, with "fingers" protruding from the middle.

[big_teee]

So there is only one magnet polarity facing the strings....unlike a standard side-by-side humbucker where one coil is south and the other north?

Do I wire the two coils the same way a standard humbucker is wired, finish wire to finish wire if they're both wound in the same direction or finish of one to start of another if they're wound in opposite directions?

David - Won't it be on the hot side if have 8000 turns per coil? I'm thinking I don't want a real hot pickup but maybe the design requires higher dc resistance to sound good? I don't know, just asking.

Thanks for the help!

As my good friend SonnyW calls it, it is the Magnetic window.
The PAF style Humbucker has 2 magnetic windows that you energize with the strings.
The North magnetic poles on one side and the South magnetic poles on the other.
The Strings and flux fields are effected by both north and south, when the strings move by.
On the Stacked Coil there is only one magnetic widow.
The coil on the bottom is not directly effected by the moving field of the strings, and is more of a dummy coil.
It is there primarily to cancel the 60 Cycle hum.
That is the mental picture I have of it.
If someone else wants to explain it without getting too Engineering deep, Please do.
T

[nickc35]

In a sense, there is only one "magnet" in a PAF-style humbucker as well. It just happens to be U-shaped, with some "fingers" that extend out of the magnet at each end and take a sharp 90-degree turn. We think of the two coils as if they lived in separate magnetic universes, but really, it's just one coil at the southy end of the magnet and another at the northy end of the same magnet. When one makes a stacked humbucker, all you're really doing is "straightening out the magnet".

Thanks for that explanation Mark. I've asked that question before and no one explained it quite the way you did. It helps a lot.

[davos]

As my good friend SonnyW calls it, it is the Magnetic window.
The PAF style Humbucker has 2 magnetic windows that you energize with the strings.
The North magnetic poles on one side and the South magnetic poles on the other.
The Strings and flux fields are effected by both north and south, when the strings move by.
On the Stacked Coil there is only one magnetic widow.
The coil on the bottom is not directly effected by the moving field of the strings, and is more of a dummy coil.
It is there primarily to cancel the 60 Cycle hum.
That is the mental picture I have of it.
If someone else wants to explain it without getting too Engineering deep, Please do.
T

Do both coils need a similar amount of turns to cancel the 60 cycle hum? Would it work for instance if one coil had 10K turns and the other had just 100? Im just thinking from a construction point of view, not tonal.

[big_teee]

Do both coils need a similar amount of turns to cancel the 60 cycle hum? Would it work for instance if one coil had 10K turns and the other had just 100? Im just thinking from a construction point of view, not tonal.

I haven't actually made this pickup, but several on here have.
On the fender stacked, I think the bottom coil is smaller, and uses finer wire.
I recommend, start making one and experiment with the turns count.
However, I don't think a coil with 100 turns will get you by.
I make an unmatched humbucker with one bobbin 42, and the other with 43, and the turn count is not equal.
It still does a good job of hum canceling.
So I think you will be able to have mismatched coils, just not sure how much.
Someone on here needs to persue this, and report back.
The problem with most forum info like this is, once someone goes through all the trial and error, they lose the willingness to share.
T

[rjb]

...However, I don't think a coil with 100 turns will get you by.
...So I think you will be able to have mismatched coils, just not sure how much.
Someone on here needs to persue this, and report back.

I'm being lazy here- I know this has been discussed before, and I could look it up- but I'm not going to.
But anyways, I think the rule of thumb for humbucking is you want the "sensing area" (coil area x #turns) to be about the same.
If you're off by 10%-20%, my guess is you won't hear any noticeable difference.
There has been at least one thread about using a large sensing coil with few turns to "humbuck" a normal single coil pickup.
Use at your own risk. If the guys who know what they're talking about aren't all on vacation, I expect someone to pipe up soon.

[Mark Hammer]

Do both coils need a similar amount of turns to cancel the 60 cycle hum? Would it work for instance if one coil had 10K turns and the other had just 100? Im just thinking from a construction point of view, not tonal.

In many instances they do, but not all instances.
I regularly tell people that you need to think of the coil like an antenna that pulls in a "station" broadcasting at 60hz. If the two coils pull in the same station, with the same signal strength, and they are opposite phase, then you will get complete cancellation. If the one antenna pulls in the station with either greater or lesser strength, then you get good, but not perfect, cancellation.

The problem they face is that two objects can't occupy the same space at the same time. If two perfect copies of the same antenna could be in the same place at once, then obviously they wouldexhibit identical sensitivity to the EMI, and you'd get perfect cancellation.

Alas, the best they can do is be very close to each other. One might safely assume that two identical coils in a dual rail pickup should provide better hum cancellation (by virtue of sensing the EMI near identically) than a RWRP neck and bridge pickup on a Tele, partly because the Tele pickups are not identical coils, and partly because they are spaced apart and don't sense the EMI source identically.

Do they HAVE to be identical and very close? Not necessarily, as the Suhr backplate illustrates. What matters is that the two coils are engineered and oriented to sense the EMI source equivalently. So, two otherwise identical coils, one "pointing" up to the strings, and a second perpendicular to the strings, might not sense the hum source equally. Result? Modest cancellation.

Pushing the idea a little further, one coil with 5000 turns of #42 around a bar magnet won't necessarily sense the EMI source identically to 5000 turns of #38 wire wound around 3/8" diameter slugs. It's not the slugs vs bar magnet per se, but the shape, resistance, and inductance of the coil (and a whole bunch of other things the more knowledgeable folks here will surely remind me of).

[big_teee]

The mini Strat sized Rail does exhibit excellent hum cancellation.
IME better than a full sized humbucker.
I never saw the need for a stacked pickup, since the IMO much better option is the Baby mini Rail Pickup.
The only possible advantage of the stacked, is it satisfies the Vintage look.
That is a future project for me is to build a stack and compare to the mini rail!
T

[rjb]

The problem they face is that two objects can't occupy the same space at the same time. If two perfect copies of the same antenna could be in the same place at once, then obviously they wouldexhibit identical sensitivity to the EMI, and you'd get perfect cancellation.

Free-associating here.
Has some mad scientist ever tried winding a coil with two parallel wires, or twisted-pair magnet wire?
Objects can't occupy the same space at the same time- but some objects can be interleaved.

[rjb]

There has been at least one thread about using a large sensing coil with few turns to "humbuck" a normal single coil pickup.

Synchronicity. This just posted in another thread: http://music-electronics-forum.com/t30193/#post268482

[big_teee]

Synchronicity. This just posted: http://music-electronics-forum.com/t30193/#post268482

So how many guys are going to let you take a Router to the vintage Strat?
T