Is there a way to find out if a PU is a humbucker or a single coil?

[JazzNote]

One of my guitars which i bought used, came with a Kent Armstrong Johnny Smith style floater with polepieces but sounds pretty much like a single coil PU. It also generates an annoying amount of hum when i turn down the volume pot, much stronger than the Johnny Smith style humbuckers of which i have installed a few on several guitars. However with the pot at its loudest setting there is no hum at all.
- Is there a way to find out if it is really a single coil without taking it apart?
- could the high amount of hum (when vol. is reduced) be proof for it to be single coil?
TIA

[John A.]

One of my guitars which i bought used, came with a Kent Armstrong Johnny Smith style floater with polepieces but sounds pretty much like a single coil PU. It also generates an annoying amount of hum when i turn down the volume pot, much stronger than the Johnny Smith style humbuckers of which i have installed a few on several guitars. However with the pot at its loudest setting there is no hum at all.
- Is there a way to find out if it is really a single coil without taking it apart?

If there are two coils, one should be above magnetic north and the other should be above magnetic south. If you take a magnet and hold it above each side of the pickup it should repel on one side and attract on the other. But it might be hard to orient things to get that effect; disassembly would be more definitive.

- could the high amount of hum (when vol. is reduced) be proof for it to be single coil?
TIA

Not necessarily. It could be that other (unshielded) wiring is acting as an antenna for EMI, it could be a grounding or other wiring issue, or it could be that the pickup is broken in some way (e.g., one of the coils is shorted out). Because the hum goes away when the volume is all the way up, that suggests to me that it is a humbucker, the pickup itself is not broken, and there's something wrong with other wiring.

[docsteve]

Take it to Nevershouldhavesoldit‘s jam session
There is a high voltage line next to the place that creates some serious hum indeed.

If the pickup only hums when you reduce the volume, there is possibly something wrong in the signal chain. I have the same issue with a pair of wireless transmitters that are only silent when the pot is on 10 or on 0. No issues with a lead, though. That’s with humbuckers and single coils.

Try a different lead or amp before you take the pickup apart. Replace the volume pot if necessary.

Edit: I saw John beat me to it.

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[Doctor Jeff]

As a slight digression, I recently got a guitar with Gretsch HiLo-trons. I have played it for months and just found out that it has single coil pickups. Apparently the HiLo-tron is one-half of a Filtertron pickup.

I have to say it is a very responsive pickup and can get growly, but overall I am loving the sound of the guitar (G6117T-HT).

It is virtually noiseless with my tube amp, which kind of surprises me.

[Cunamara]

The Kent Armstrong floating Johnny Smith style pickup is a humbucker. His single coil pickups have the polepieces in the center of the pickup cover, not along one edge. He does make a floating single coil pickup which is immediately and obviously different from any of his humbuckers.

The symptoms you are describing point at a wiring problem, possibly a ground issue versus bad solder joint. This happened on my archtop guitar and it turned out that the problem was that the Mogami shielded wire from the controls was not properly grounded at the jack; fixing that eliminated the symptoms.

[rpjazzguitar]

The Kent Armstrong floating Johnny Smith style pickup is a humbucker. His single coil pickups have the polepieces in the center of the pickup cover, not along one edge. He does make a floating single coil pickup which is immediately and obviously different from any of his humbuckers.

The symptoms you are describing point at a wiring problem, possibly a ground issue versus bad solder joint. This happened on my archtop guitar and it turned out that the problem was that the Mogami shielded wire from the controls was not properly grounded at the jack; fixing that eliminated the symptoms.

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Common problem is that tightening the nut around the jack rotates the jack inside the guitar. Eventually, it can pull the wires off the pot. There's a tool that reportedly holds the jack still while you tighten the nut.

[ThatRhythmMan]

\

Common problem is that tightening the nut around the jack rotates the jack inside the guitar. Eventually, it can pull the wires off the pot. There's a tool that reportedly holds the jack still while you tighten the nut.

I use this Allparts jack tightener.


https://a.co/d/bFAhDSr


Sent from my iPhone using Tapatalk

[JazzNote]

If there are two coils, one should be above magnetic north and the other should be above magnetic south. If you take a magnet and hold it above each side of the pickup it should repel on one side and attract on the other. But it might be hard to orient things to get that effect; disassembly would be more definitive.

Not necessarily. It could be that other (unshielded) wiring is acting as an antenna for EMI, it could be a grounding or other wiring issue, or it could be that the pickup is broken in some way (e.g., one of the coils is shorted out). Because the hum goes away when the volume is all the way up, that suggests to me that it is a humbucker, the pickup itself is not broken, and there's something wrong with other wiring.

Thanks John!
I took the whole assembly out of the guitar and at this moment i'm fooling around with a magnet, comparing it's reaction also to another KA pickup, one of which i know for sure to be a humbucker. The magnetic behaviour of the two pickups are quite different. The same magnet placed on the humbucker pulls on one side (the side with polepieces) and as you write repels on the other side (the side with no polepieces), on the pickup in question it pulls on both sides, but strong on the side with polepieces, much weaker on the other side. What does this indicate? The resistance, measured with a ohms meter reads 7.86 k

[JazzNote]

The Kent Armstrong floating Johnny Smith style pickup is a humbucker. His single coil pickups have the polepieces in the center of the pickup cover, not along one edge. He does make a floating single coil pickup which is immediately and obviously different from any of his humbuckers.

The symptoms you are describing point at a wiring problem, possibly a ground issue versus bad solder joint. This happened on my archtop guitar and it turned out that the problem was that the Mogami shielded wire from the controls was not properly grounded at the jack; fixing that eliminated the symptoms.

I checked and found no bad solder point. However, i found that different wiring schemes are recommended. Eg. Bartolini has the output jack on the pot's left slug, the PU in the middle, while Seymor Duncan and Benedetto show the opposite, the output in the middle, the PU on the left. In my case the PU was in the middle. After changing that (reversing PU and output) the hum decreased audibly. I measured the resistances at the PU and the output before and after changing the connections, and found different readings for both. The pickup however, still sounds like a single coil. I had Kent wind a custom floater with both options for me a while ago (humbucker with a tap wire for one coil) so i'm wondering if this might also be a special order, but what could it be as no tap is visible ....

[Cunamara]

What does the sticker underneath the pickup say?

Every appearance is that it is a humbucker. Whether it is one of the Asian made ones versus a "hand wound" US one isn't clear from looking at the top of it. (FWIW, the Asian ones are also hand wound- by a guy trained by Kent; those pickups get a bad rap, but Kent says they sound exactly like the same model pickups he winds in Vermont. The materials and designs are the same). 7.86K is consistent with being a humbucker. A single coil is typically around half that. That you got different readings after changing the wiring, assuming you're taking those readings at the jack, makes sense because you're getting the DC resistance of the entire circuit, not just the pickup. It's possible that reversing the input lugs on the volume control changes the grounding of the circuit; it's also possible that one of those two solder joints was in fact bad and now you've fixed it.

If you are comparing the floating mini humbucker to a full size one, it's going to sound more like a single coil relatively speaking. These are inherently brighter and more focused pickups than a PAF. Especially if you're comparing it to a PAF that is mounted in a guitar versus floating.

[sgosnell]

There are multiple ways of wiring a pickup through potentiometers, and they all work, mostly. Some sound better to me than others.

That pickup certainly has the humbucker construction method. A single-coil pickup should have the polepieces in the center, because there is only one coil. It's possible to produce a pickup with two coils but with only one connected, commonly known as coil-splitting. Those usually have 4 or more wires, though, and use a push-pull pot to provide both humbucking and single-coil modes as the player desires. The magnet test can be deceptive, because magnetic fields are often rather broad, especially when a metal cover is in use. It's also possible to have no magnets in the second coil. If there are only two wires from the pickup, it could be either a humbucker or single-coil. But I would bet that pickup is a humbucker. Wiring makes a difference. There are many wiring diagrams available on the internet, so you may want to try some and see how you like them, and how noisy they are. I prefer this one, but YMMV.

Bravo wiring diagram.pdf

[JazzNote]

What does the sticker underneath the pickup say?

Every appearance is that it is a humbucker. Whether it is one of the Asian made ones versus a "hand wound" US one isn't clear from looking at the top of it. (FWIW, the Asian ones are also hand wound- by a guy trained by Kent; those pickups get a bad rap, but Kent says they sound exactly like the same model pickups he winds in Vermont. The materials and designs are the same). 7.86K is consistent with being a humbucker. A single coil is typically around half that. That you got different readings after changing the wiring, assuming you're taking those readings at the jack, makes sense because you're getting the DC resistance of the entire circuit, not just the pickup. It's possible that reversing the input lugs on the volume control changes the grounding of the circuit; it's also possible that one of those two solder joints was in fact bad and now you've fixed it.

If you are comparing the floating mini humbucker to a full size one, it's going to sound more like a single coil relatively speaking. These are inherently brighter and more focused pickups than a PAF. Especially if you're comparing it to a PAF that is mounted in a guitar versus floating.

There's no sticker, but according to the apperance and the guitar it was mounted on i don't think it's an asian model. I did check the wiring before i canged it, and it was all fine. I took the readings at the jack, and at the pickup. Since i own several guitars with floaters like Gibson Johnny Smith originals, some BJB's, some Kent Armstrong 6 pole and 12 pole, one Dommenguet Jazzbucker (switchablebetween single coil and humbucker), also i had a Biltoft P90 on a guitar which i replaced again with the KA split Humbucker/Single Coil mentioned above, i replaced asian PU's with Bartolinis (which i also removed a while ago). So i do believe that i can distinguish between a typical single coil floater and a floating humbucker.

There are multiple ways of wiring a pickup through potentiometers, and they all work, mostly. Some sound better to me than others.

That pickup certainly has the humbucker construction method. A single-coil pickup should have the polepieces in the center, because there is only one coil. It's possible to produce a pickup with two coils but with only one connected, commonly known as coil-splitting. Those usually have 4 or more wires, though, and use a push-pull pot to provide both humbucking and single-coil modes as the player desires. The magnet test can be deceptive, because magnetic fields are often rather broad, especially when a metal cover is in use. It's also possible to have no magnets in the second coil. If there are only two wires from the pickup, it could be either a humbucker or single-coil. But I would bet that pickup is a humbucker. Wiring makes a difference. There are many wiring diagrams available on the internet, so you may want to try some and see how you like them, and how noisy they are. I prefer this one, but YMMV.

Bravo wiring diagram.pdf

Yes, it has the humbucker construction method. What leaves me puzzled, is therefore not expecting a single coil sound from it. Both wirings used (see my post #9 above) give me a single coil sound .....

[sgosnell]

I couldn't possibly say without disassembling the pickup, but again it's possible that the second coil is a dummy, without magnets. That's an attempt to get a single-coil sound while still bucking hum.

[Herbie]

I use this Allparts jack tightener.


https://a.co/d/bFAhDSr


Sent from my iPhone using Tapatalk

Amazing! There is a gadget even for this!

[ThatRhythmMan]

Amazing! There is a gadget even for this!

It’s not even the only tool designed for the job. Check this one out.

https://a.co/d/5qmnGbh


Sent from my iPhone using Tapatalk

[JazzNote]

Amazing! There is a gadget even for this!

Good for "professionals" who use it once a week. For me that would be avg. once every two years max. So i stick to what i believe to be Mark Campellone's invention, using a piece of slightly angled wood - forcing it in slightly and hold it, to keep the jack from turning when tightening the nut.