Noise With My Lp - Grounding Issue?

[roahboah]

Hi,

I'm a new member to the forums and have been a reader for awhile - great, great information here!

I've posted this question in a couple of other places, but I haven't found anyone yet with the same symptoms.

I have a 70s LP Custom that I recently put some Fralin HBs into, and I'm loving the pickups.

However, since the new PUs have been put in, I've noticed noise where there was none before.

The noise is more noticeable at high gain, and is also somewhat dependent on proximity to my amplifier. It's not dependent on whether I'm holding the strings or not.

The most significant thing in my beginner's brain that might point to the issue, though, is the fact that the noise completely vanishes when I put the LP in the in-between position on the PUs. It's not wired out-of-phase or anything like that - just a vanilla LP configuration. It's quite amazing - the noise is completely gone in that position. I feel like if it was a specific shielding thing, then noise might remain in any PU position - but I could certainly be wrong. These were coverless PUs, so I did the diligence and wrapped the PUs with copper tape and grounded said tape to the PU frame just to make sure that wasn't the issue, but there was no change.

Has anyone experienced an issue similar to this one? I'm kinda baffled!

Thanks in advance, and please let me know if you want more information.

roah

[JoeAArthur]

Based on the symptoms, it sounds like your pickups.

In order for a pickup to be as close to humbucking as possible, both coils need to be wound as identical but with opposite polarity as possible. Unfortunately this isn't really possible with hand-wound coils. I don't know about Fralin, but some makers are claiming that mismatched coils provide a superior sound.

Whatever, the end result is a humbucking pickup that isn't really full humbucking and it will pick up more noise, especially as you get closer to the amp - the power transformer puts out lots of hum stuff.

The reason it sounds less hummy in the middle position is that you have two mismatches that balance each other out better and get closer to true humbucking.

[roahboah]

Based on the symptoms, it sounds like your pickups.

In order for a pickup to be as close to humbucking as possible, both coils need to be wound as identical but with opposite polarity as possible. Unfortunately this isn't really possible with hand-wound coils. I don't know about Fralin, but some makers are claiming that mismatched coils provide a superior sound.

Whatever, the end result is a humbucking pickup that isn't really full humbucking and it will pick up more noise, especially as you get closer to the amp - the power transformer puts out lots of hum stuff.

The reason it sounds less hummy in the middle position is that you have two mismatches that balance each other out better and get closer to true humbucking.

Very interesting information - thanks! I was not aware of problems such as these in hand-wound pickups. I guess that explains why copper etc. didn't really help with the noise. Do you have any idea how off the winds would have to be to begin picking up noise in this fashion? I might touch base with Fralin to see if this is a common occurrence.

thanks,

roah

[JoeAArthur]

Very interesting information - thanks! I was not aware of problems such as these in hand-wound pickups. I guess that explains why copper etc. didn't really help with the noise. Do you have any idea how off the winds would have to be to begin picking up noise in this fashion? I might touch base with Fralin to see if this is a common occurrence.

thanks,

roah

No. In the interest of being totally political correct concerning pickup hype, I would encourage you to contact Fralin.

[roahboah]

Very interesting information - thanks! I was not aware of problems such as these in hand-wound pickups. I guess that explains why copper etc. didn't really help with the noise. Do you have any idea how off the winds would have to be to begin picking up noise in this fashion? I might touch base with Fralin to see if this is a common occurrence.

thanks,

roah

No. In the interest of being totally political correct concerning pickup hype, I would encourage you to contact Fralin.

Thanks for the info.

[Fix_Metal]

well it seems like you've soldered them wrong. I mean, if they are noisy in what is supposed to be an humbucking position, that's not right.

What are your PUs like? 2,3 or 4 conductors?

[roahboah]

well it seems like you've soldered them wrong. I mean, if they are noisy in what is supposed to be an humbucking position, that's not right.

What are your PUs like? 2,3 or 4 conductors?

They are 4-conductor.

[Mike Sulzer]

Hand wound pickups can cancel hum very well. It is only necessary to use a counter to get the number of turns the same on the two coils. Fralin sells a model called the Unbucker with more wound on the screw coil. Is this what you have? If so, you cannot expect it to cancel hum as well. (Although it is possbile to design pole pieces with different sensitivities in order to compensate for the turns, but I do not think the Unbucker does.) It would be posible to wind and connect a pair of Unbuckers for good cancelation with both on, but this is the first I have have heard that it might actually work that way.

Based on the symptoms, it sounds like your pickups.

In order for a pickup to be as close to humbucking as possible, both coils need to be wound as identical but with opposite polarity as possible. Unfortunately this isn't really possible with hand-wound coils. I don't know about Fralin, but some makers are claiming that mismatched coils provide a superior sound.

Whatever, the end result is a humbucking pickup that isn't really full humbucking and it will pick up more noise, especially as you get closer to the amp - the power transformer puts out lots of hum stuff.

The reason it sounds less hummy in the middle position is that you have two mismatches that balance each other out better and get closer to true humbucking.

Very interesting information - thanks! I was not aware of problems such as these in hand-wound pickups. I guess that explains why copper etc. didn't really help with the noise. Do you have any idea how off the winds would have to be to begin picking up noise in this fashion? I might touch base with Fralin to see if this is a common occurrence.

thanks,

roah

[JoeAArthur]

Hand wound pickups can cancel hum very well. It is only necessary to use a counter to get the number of turns the same on the two coils. Fralin sells a model called the Unbucker with more wound on the screw coil. Is this what you have? If so, you cannot expect it to cancel hum as well. (Although it is possbile to design pole pieces with different sensitivities in order to compensate for the turns, but I do not think the Unbucker does.) It would be posible to wind and connect a pair of Unbuckers for good cancelation with both on, but this is the first I have have heard that it might actually work that way.

Based on the symptoms, it sounds like your pickups.

In order for a pickup to be as close to humbucking as possible, both coils need to be wound as identical but with opposite polarity as possible. Unfortunately this isn't really possible with hand-wound coils. I don't know about Fralin, but some makers are claiming that mismatched coils provide a superior sound.

Whatever, the end result is a humbucking pickup that isn't really full humbucking and it will pick up more noise, especially as you get closer to the amp - the power transformer puts out lots of hum stuff.

The reason it sounds less hummy in the middle position is that you have two mismatches that balance each other out better and get closer to true humbucking.

Very interesting information - thanks! I was not aware of problems such as these in hand-wound pickups. I guess that explains why copper etc. didn't really help with the noise. Do you have any idea how off the winds would have to be to begin picking up noise in this fashion? I might touch base with Fralin to see if this is a common occurrence.

thanks,

roah

You are absolutely correct - it is possible that hand wound can cancel hum, assuming that the "hand wound" coil is as close to "computer wound" as possible. However, if "hand wound" follows the typical "scatter wound" associated with hand winding, the chances of obtaining humbucking operation is closer to none than it is to slim.

[roahboah]

Hand wound pickups can cancel hum very well. It is only necessary to use a counter to get the number of turns the same on the two coils. Fralin sells a model called the Unbucker with more wound on the screw coil. Is this what you have? If so, you cannot expect it to cancel hum as well. (Although it is possbile to design pole pieces with different sensitivities in order to compensate for the turns, but I do not think the Unbucker does.) It would be posible to wind and connect a pair of Unbuckers for good cancelation with both on, but this is the first I have have heard that it might actually work that way.

Based on the symptoms, it sounds like your pickups.

In order for a pickup to be as close to humbucking as possible, both coils need to be wound as identical but with opposite polarity as possible. Unfortunately this isn't really possible with hand-wound coils. I don't know about Fralin, but some makers are claiming that mismatched coils provide a superior sound.

Whatever, the end result is a humbucking pickup that isn't really full humbucking and it will pick up more noise, especially as you get closer to the amp - the power transformer puts out lots of hum stuff.

The reason it sounds less hummy in the middle position is that you have two mismatches that balance each other out better and get closer to true humbucking.

Very interesting information - thanks! I was not aware of problems such as these in hand-wound pickups. I guess that explains why copper etc. didn't really help with the noise. Do you have any idea how off the winds would have to be to begin picking up noise in this fashion? I might touch base with Fralin to see if this is a common occurrence.

thanks,

roah

No, these aren't Unbuckers. They're PAFs, basically.

thanks,

roah

[Mike Sulzer]

[JoeAArthur]

Have you tried this? No special precautions are necessary to make a really goodhumbucker by hand winding. I have done it many times. The number of turns is the most important parameter. Differences in how the coils are wound can affect the capacitance somewhat, and so make a difference in the cancelation of higher harmonics, but in practice this is a very small effect.

If two opposite coils do not pickup the same equal amount of hum and in reverse polarity then they cannot be effectively humbucking.

Capacitance of your coils do not even enter into the humbucking equation. Only equal and out of phase signals can cancel effectively.

If you sloppy wind your two coils totally at random but they pickup the same equal hum signal but out of phase, more power to you.

And the next time I play poker, I will get a royal flush on the first five cards I am dealt every time without a problem.

[GregP]

In all fairness, the 2 coils don't have to be absolutely identical to effectively cancel most hum. Heck, I would think that the differences in polepieces (slugs vs screws) within a typical humbucker are going to create a bigger difference than a few extra winds here or there. It would be a huge overstatement to say that handwound pickups won't cancel hum effectively.

[JoeAArthur]

In all fairness, the 2 coils don't have to be absolutely identical to effectively cancel most hum. Heck, I would think that the differences in polepieces (slugs vs screws) within a typical humbucker are going to create a bigger difference than a few extra winds here or there. It would be a huge overstatement to say that handwound pickups won't cancel hum effectively.

I didn't say that they had to be absolutely identical. That would be a mis-statement as the windings have to be reverse. Tosses out identical into the trash heap.

The difference between slugs and polepieces have absolutely nothing to do with hum pickup. It does make a difference in picking up the string vibration, but only the coils pickup hum. Like an antenna.

Carefully hand wound pickups can be made to cancel hum effectively. But only if the hand winder avoids scatterwinding.

I am not talking "tone", you can argue that all you want.

But even the patent (as in P.A.F) claims that equal but reverse wound coils of opposite magnetic polarity are necessary to achieve the humbucking effect.

[Mike Sulzer]

Joe, you obviously have never tried this. Do you think the original PAFs from the 50s were "computer wound"? Nobody had a computer outside of a (large) lab then.

The capacitance between the windings reduces the output at high frequencies. If two coils in series have different capacitances the output voltages of hum at the higher frequencies are different and will not cancel so well. A minor but real effect.

What is the sarcasm for? There is nothing bad about being wrong, but you are making it hard for you to ever admit it.

Greg, the longer thinner screw matches with the thicker shorter slug pretty well, but I think you are right about this being the limit. Humbuckers with coils with identical poles can be better.

[GregP]

[edit: cross-posted]

I'll admit to being unsure about the screws... surely they factor into the entire equation of the pickup's ability to... er... pick-up... otherwise we wouldn't need polepieces at all? What you say seems to make sense, Joe, about the coils being the only factor in picking up certain things, so I can't say I feel as confident anymore. But nor am I completely convinced yet.

However, don't be pedantic about the 'reversed' coils. You know what I meant. That doesn't toss the idea into the trash heap as you imply. If the UnBucker still bucks SOME of the hum (and it does), and if one coil of a humbucker, combined with a coil of a separate humbucker (popularized by PRS but found in other manufacturers) will cancel a great deal of hum, and if one coil of a humbucker, combined with a single-coil middle pickup can cancel mucho hummo, then it stands to reason that as long as the two coils have at least been made with "equal but reverse" in mind, then they will cancel most of the hum.

To clarify that last phrase, I mean that the pickup maker/winder was at least TRYING to make them equal (even if the total length of the coils had slight discrepancies). That being the case, you're going to have most of the hum cancelled.

I can't say that you're "wrong", full stop. No way would I do that. But I think that it's unlikely to be due to the Fralin (high quality, with winds likely carefully counted) pickups and more likely to be due to a rewiring mishap or oversight. I'm not sure what effect the 'copper tape wrapping' might have, but I'm wondering....

To the OP: have you changed environments at all? Did you intentionally take note of the 'lack' of hum in the old pickups when standing near the sources of interference? Is it possible that it's just close scrutiny that is making you notice now (scrutiny due to having changed your own pickups and wanting to check them carefully), and that the old pickups might have passed along the same amount of hum in the same environment, gain levels, and proximity to interference but you just never thought to scrutinize previous to the change? When you say it's not the "touching the strings", does that mean that touching the strings has no effect whatsoever? Also, regarding the copper tape-- how did you affix it?

[Mike Sulzer]

The pole pieces in a humbucker have two purposes:

1. Magnetize the strings. (The magnet magnetizes the poles pieces; the pole pieces magnetize the strings.

2. Amplify external magnetic fields (from the vibrating strings, or external interference fields).

It is the second purpose that is in question here. Nearly all magnetic sensors use a ferromagnetic core to amplify the field being sensed. For example, nearly all AM radios sense the magnetic part of radio wave using a coil with a ferrite core. A ferrite that functions at frequencies up to about 1.6 MHz, or higher, is used. Without the ferrite core, it would not work so well, and one would probably need to use a long wire to sense the electric field from the wave.

The short steel cores used in a guitar pickup do not have a huge amplifyig effect, but it is there. This is easy to demonstate. Connect a humbucker to an amplifier. Make sure that it is well-shielded against electrical fields. Now remove the screws one at a time. If there are interfering magnetic fields present, the hum increases some as each screw is removed.

[JoeAArthur]

Joe, you obviously have never tried this. Do you think the original PAFs from the 50s were "computer wound"? Nobody had a computer outside of a (large) lab then.

The capacitance between the windings reduces the output at high frequencies. If two coils in series have different capacitances the output voltages of hum at the higher frequencies are different and will not cancel so well. A minor but real effect.

What is the sarcasm for? There is nothing bad about being wrong, but you are making it hard for you to ever admit it.

Greg, the longer thinner screw matches with the thicker shorter slug pretty well, but I think you are right about this being the limit. Humbuckers with coils with identical poles can be better.

I'm not sure what you mean.

I never said that hand wound coils couldn't be as close to humbucking as humanly possible. I said that scatter wound coils had a slim to none chance. If you believe there is no difference between a precise hand wound coil and the scatter wound then maybe I understand the confusion.

Hum is not present at high frequencies. That's why it is called hum. The frequency (in the USA) is normaly 60hz. There would have to be a heck of a lot of capacitance in those coils to reduce it by cutting off the high frequencies.

You ask if I've tried this, and you claim that it is obvious that I haven't. I don't know what you mean. So let me explain my position.

No, I have never wound a single pickup coil in my life. Over the last 35 years I have only been a consumer of pickups. I know I have bought way too many pickups in that time frame. If only I could have known then what I know now.

In each case, a scatter wound humbucker has been less humbucking than a precisely hand wound humbucker. In each case, a machine wound humbucker has been more humbucking than even the best of the precisely hand wound humbuckers.

So, if you are attempting to claim I have no basis to make my comments because I have never wound a pickup coil, that would be like claiming I have no basis to comment on my car's mileage because I have never made my own gasoline.

And you can take that last comment as sarcasm if you want.

[JoeAArthur]

The pole pieces in a humbucker have two purposes:

1. Magnetize the strings. (The magnet magnetizes the poles pieces; the pole pieces magnetize the strings.

2. Amplify external magnetic fields (from the vibrating strings, or external interference fields).

It is the second purpose that is in question here. Nearly all magnetic sensors use a ferromagnetic core to amplify the field being sensed. For example, nearly all AM radios sense the magnetic part of radio wave using a coil with a ferrite core. A ferrite that functions at frequencies up to about 1.6 MHz, or higher, is used. Without the ferrite core, it would not work so well, and one would probably need to use a long wire to sense the electric field from the wave.

The short steel cores used in a guitar pickup do not have a huge amplifyig effect, but it is there. This is easy to demonstate. Connect a humbucker to an amplifier. Make sure that it is well-shielded against electrical fields. Now remove the screws one at a time. If there are interfering magnetic fields present, the hum increases some as each screw is removed.

Wow. Where do you get this stuff from? It is so far from reality it is not even worth disputing!!

[GregP]

I dunno, Joe. I'm willing to be open-minded, but like you, I'm a consumer (not a maker) who happens to be weirdly obsessive about learning this kind of stuff, and your argument is missing a few things:

1. If the two coils are scatter-wound, using a counter, by the same person, there is a very good chance actually that they'll be almost perfectly humbucking. The law of averages factors in here-- yes, one wrap might be shorter than the next (due to diagonal displacement, etc), but spread over thousands of winds, there is likely to be pretty much the same length of wire used. Particularly if, like I say, they're wound by the same person. That person is likely to have the same approach to winding and will naturally wind each with similar displacements, resulting in (averaged over thousands of winds) a pretty similar pickup. By measuring inductance, they have an additional tool to make sure that the coils match.

2. The hum is not a static 60/50 cycle sine wave. Therefore there are higher-order harmonics present as well.

3. I honestly have no concrete knowledge yet, but Mike's explanation of pickup construction at least has the appearance of basis in fact, and lines up with common sense. It's common sense that the magnets will have an effect on the hum "picked up," though I'm willing to admit that there might be physics that I'm unaware of. Rather than simply saying it's not worth disputing, I for one would find value in an actual explanation as to why the magnets are not a factor in picking up hum. I don't mind if my common sense is proven wrong-- the world is full of discrepant knowledge and phenomenon. ;-)

I think it goes without saying that a scatterwound pickup is less precise than a computer-driven factory wind. As such, it's a given that the humbucking will be "X" degrees more effective with a factory wind. The issue I'm trying to convey which you still seem to disagree with is the "degree" to which this difference is an impact. It's by overestimating this degree of difference that you're at least *possibly* insisting on your interpretation of the OP's problem as being the right one without question. I think the difference in effectiveness is infantessimal to the degree that my instinct is to look to other potential causes. You have to trouble-shoot all possibilities rather than make one diagnosis and stick to it.

IOW, your theory is valid, but by overestimating the differences between scatterwound coils, you're shutting out the possibility that there are other factors.

For example: it seems like the OP has wrapped conductive copper tape directly to the coils themselves. Even though the coils generally have cloth tape around them, it's at least possible that something has gone amuck with the shielding tape. For that matter, though he says the new pickups are "open," he doesn't say whether the previous ones were open or covered. Even with copper tape around the coils, the top of an 'open' pickup still exposes the coils more than a covered pickup does.

Another example: maybe the OP just never noticed this effect (increased noise by proximity to amplifier) until he truly scrutinized his replacement job.

Another possibility: maybe the previous pickups were LESS effective and the noise of the middle position was just more noticeable than now; it could be the more remarkable difference in noise that's drawing his attention to it than the noise floor itself

Also possible: faulty wiring. Wouldn't be surprising for someone new to soldering and rewiring to make some faulty connections

--

Greg

[Mike Sulzer]

"Hum is not present at high frequencies."

Joe, most interference is not the fundamental, but harmonics, which extend up into the KHz range. Magnetic fields containing such harmonics can be produced when electrical currents are chopped by light dimmers or from circuitry in CRT monitors, etc.

"Wow. Where do you get this stuff from? It is so far from reality it is not even worth disputing!!"

AM radios do not use ferrite core antennas? They sure do. I am not the only one to have done the test that described above that shows how the hum cancelation descreases as you remove the screws.

[metallisomething]

I use EMG-81's and 85's and get a brutal buzz. It dies down a little but when i hold something, like a pot or pickup...But the instructions clearly tell you not to ground them. Even when the volume on the pickups is down i can hear buzzing. It's driving me crazy and I don't know enough about it to figure it out. Its a guitar I built...two volume and one tone.

[GregP]

My first thought is that one of the pickups has a faulty preamp. Although encased in epoxy (or whatever), it's still a circuit with components, and may fail. Just a thought, though.

[Mike Sulzer]

Check the wiring carefully, too. Coud wires be broken or reversed at the output jack or pots?

[Aka Nameless]

Metallisomething, the fact that you hear hum when both volumes are at 0 makes me think that your tone pot's casing isn't grounded and is pickup up noise with no way to ground it, which is bleeding into the unshielded hot wire from the tone pot to the output jack. Or.. if you shielded your guitar, maybe the shielding isn't grounded properly and noise is building up in the shielding with no way to ground, so your unshielded hot wire from tone to output jack is picking up the noise like an antenna. Just a guess.