need schematic for hum cancelling jazz bass pickups

[Joe Gwinn]

So your test shows something that is obvious. So what? It does nothing towards proving what you want to show: that individual coils connected in series are significantly brighter than a similar single large coil. I guess you realize that, but given your description of the test, how was anyone else supposed to know what you were or were not trying to prove with it?

Mike, the shape of the coils does not matter. If one has a number of coils that are far enough apart and/or mutually orthogonal, so there is insignificant magnetic coupling, the inductance of these coils in series will be the sum of the individual inductances taken one at a time. If some of the coils have significant magnetic coupling, the series inductance can be higher (series aiding) or lower (series opposing) than the simple sum. If all the coils are arranged and oriented as for a single big coil, the overall series inductance will be proportional to the square of the total number of turns.

One easily demonstrate this. Take two bobbins with say 5000 turns of #42 on them and wire them in series with enough wire that they can be at least six inches apart. Measure the inductance with the coils well separated, and then whit the coils next to each other on a common non-metallic core. This is done twice, with one coil flipped over. This will yield three inductances. Wide apart coils will yield the middle value.

[Mike Sulzer]

Yes, that is right. last night I demonstrated the increase and decrease of the inductance with two coils (intended as individual string coils for a bass pickup). The increase or decrease over the simple sum is less than 10%. This is relevant to pickup design because it shows that the inductance of a bass pickup made from an individual coil for each string is less when the coils are wired in alternating phase in order to make a humbucker rather than all in phase. However, the output will be less as well, and if one winds on more turns the inductance will rise as well as the output. Hard to fool mohter nature.

To test David's claim it is necessary to make the equivalent single coil pickup, measure the inductances of both, and then listen to them both.

Mike, the shape of the coils does not matter. If one has a number of coils that are far enough apart and/or mutually orthogonal, so there is insignificant magnetic coupling, the inductance of these coils in series will be the sum of the individual inductances taken one at a time. If some of the coils have significant magnetic coupling, the series inductance can be higher (series aiding) or lower (series opposing) than the simple sum. If all the coils are arranged and oriented as for a single big coil, the overall series inductance will be proportional to the square of the total number of turns.

One easily demonstrate this. Take two bobbins with say 5000 turns of #42 on them and wire them in series with enough wire that they can be at least six inches apart. Measure the inductance with the coils well separated, and then whit the coils next to each other on a common non-metallic core. This is done twice, with one coil flipped over. This will yield three inductances. Wide apart coils will yield the middle value.

[Joe Gwinn]

Yes, that is right. last night I demonstrated the increase and decrease of the inductance with two coils (intended as individual string coils for a bass pickup). The increase or decrease over the simple sum is less than 10%. This is relevant to pickup design because it shows that the inductance of a bass pickup made from an individual coil for each string is less when the coils are wired in alternating phase in order to make a humbucker rather than all in phase. However, the output will be less as well, and if one winds on more turns the inductance will rise as well as the output. Hard to fool mother nature.

The 10% effect is because air coils don't couple all that well. Were they side-by-side or one atop the other? Atop gives greater coupling. Or, try it with iron cores and you will get far closer to the full N^2 effect.

To test David's claim it is necessary to make the equivalent single coil pickup, measure the inductances of both, and then listen to them both.

One can also do some direct measurement and computation. If one measures a winding with all other windings open-circuited, one will get the inductance of that coil alone. If one then measures in pairs, taking two measurements per pair, reversing one winding between measurements, one will be able to compute the mutual inductance. In a little while, one will know all self and mutual inductances. From this, one can compute the inductance of any connection arrangement of those coils.

By the way, a 10% difference would be quite audible.

[David Schwab]

To test David's claim it is necessary to make the equivalent single coil pickup, measure the inductances of both, and then listen to them both.

Now this is the thing, you have to listen to them. None of us actually know what the inductance is on a Wal pickup, or its individual coils. I have the pickup here, but no way to measure it.

Do we actually know that making two pickups in different ways (single coil vs/ multiple coils), but measuring the same inductance will indeed make them sound the same? Why would we think this is the case? Inductance is clearly one element to a pickup.

As an example we can take hum canceling Jazz bass pickups. One way to do this is to split the pickup into two halves, so each half handles two strings. Otherwise the pickup is just as it was, in regards to the magnets and general form factor. The general consensus in that they sound different enough from single coils that some people don't care for them. So if winding each half to equal the inductance of a single coil version made it sound the same, this would be an easy thing to do. But apparently it isn't. Or even just trying to make it sound the same regardless of inductance.

I'm just starting to work on some prototypes for Jazz bass pickups. As a control, I'm winding a standard single coil Jazz pickup. Once I get that to sound the way I want, I am going to make a split coil version and see if I can make them sound the same. Then I plan on making a four coil version and seeing how that differs. It would be nice to measure the inductance of these tests, but since I don't own a meter I have to do it by ear.

[Joe Gwinn]

Now this is the thing, you have to listen to them. None of us actually know what the inductance is on a Wal pickup, or its individual coils. I have the pickup here, but no way to measure it.

Does the pickup have or can it be made to have a pair of leads for each and every individual coil? If yes, then one can measure the effects. This has the advantage that the magnetic structure does not change, making the comparisons more direct.

[David Schwab]

Does the pickup have or can it be made to have a pair of leads for each and every individual coil? If yes, then one can measure the effects. This has the advantage that the magnetic structure does not change, making the comparisons more direct.

Yes. Each coil is connected to a circuit board. But they can be disconnected and taken out separately.

I'm going to be making a copy of this pickups, so I can wire it any way I like.

[Mike Sulzer]

Does the pickup have or can it be made to have a pair of leads for each and every individual coil? If yes, then one can measure the effects. This has the advantage that the magnetic structure does not change, making the comparisons more direct.

Exactly. I have made a four coil bass pickup, 6000 turns per coil. Now I am making one with the same core structure that will have a single coil around the core structure of 6000 turns.

Yes, David, there should be some difference between a single coil and 4 coils, unless they are like the square coil thing I showed earlier where there is nearly perfect current cancelation along the interior paths and one long side. The four round coils have some coupling between them; if they are wired for the string signals to be in phase, then the total inductance is lowered a bit (order of 10%) below the sum of the four individuals. The signal should be lowered a coresonding amount, too, but I have not made that measurement yet. I doubt that you can accomplish anything like the major effect in sound that you have been talking about, but we shall see.

I have started measuring the four coil pickup, but this whole project will take at leasat another week or two.

[David Schwab]

Exactly. I have made a four coil bass pickup, 6000 turns per coil. Now I am making one with the same core structure that will have a single coil around the core structure of 6000 turns.

Why 6,000? Try 10,000, and wind eight coils. Then it will match the example at hand. The point was that with all eight coils in series it reads 20k. Then try winding two 10k coils and wire them in series and tell me what it sounds like. I already know because I've heard and wound my own examples of that. That's a big difference from four coils wound with 6,000 turns. That would never sound muddy. That sounds like you are setting this up so you have conformation that you are right. Stick to the specs please.

Yes, David, there should be some difference between a single coil and 4 coils, unless they are like the square coil thing I showed earlier where there is nearly perfect current cancelation along the interior paths and one long side. The four round coils have some coupling between them; if they are wired for the string signals to be in phase, then the total inductance is lowered a bit (order of 10%) below the sum of the four individuals. The signal should be lowered a coresonding amount, too, but I have not made that measurement yet.

They are round coils, and they are all in phase across a row. All the coils are wound in the same direction, and are set up like a humbucker with opposite magnetic polarity and wired up start to start.

Bartolini uses square bobbins and poles. That's part of his patent.

The Wal pickup uses round bobbins and round poles.
Once again, it looks like this:

I doubt that you can accomplish anything like the major effect in sound that you have been talking about, but we shall see.

Mike, this is where you baffle me. These pickups already exist. It's already been done. It works. I even posted sound clips. Both myself and Marco have made our own versions. I have the real pickup here and studied it, and I'm making mine as close to the real thing as possible. So I know how it was wound, etc. This pickup sounds very different from other bass pickups.

You are talking like it's some idea I proposed that hasn't been tried out yet. Intsead of trying to prove if it happens, how about trying to find out why it happens.

[Mike Sulzer]

Why 6,000?

I do not want a muddy bass pickup.

In any case, If four coils are brighter than one large one, it should happen with fewer turns as well. This should be something that is a bit more general if it is true. In fact, you claimed it was more general.

Originally Posted by Mike Sulzer:
"That Gibson EB-4L does not look as though it has nearly as much wire as a mudbucker."

You:

Ya think? The question is; why wold they make the pickup with four coils and not two? Do you think they were just bored? I mean they had to actually tool up for that pickup. They must have felt their was a need for it.

And looky here... another one:

....


Why would you expect me to be convinced by and A-Z listening test when only you have heard the Z?

And if accuse me of being dishonest again, I will have to complain to the moderator! (no, just joking!)

[David Schwab]

I do not want a muddy bass pickup.

In any case, If four coils are brighter than one large one, it should happen with fewer turns as well. This should be something that is a bit more general if it is true. In fact, you claimed it was more general.

Not really, because as you wind more wire you reach a point of diminishing returns. A low wind pickup regardless of how many coils is going to sound bright. 10,000 turns on the Wal bobbins comes out to 2.5k. That's pretty low. What's 6,000 turns going to be?

Another way to look at it is take something like a Gretsch Filter'tron. Both coils in series are 4k. Then take a Duncan JB. Both coils in series are 16.4k. Which one is going to sound brighter?

The whole point of this is a 20K pickup should be very muddy, but that is not the case with the Wal pickup.

[Mike Sulzer]

A low wind pickup regardless of how many coils is going to sound bright.

No. As you continue to take turns off, you move the resonance out of the range (above) of the instrument/electronics and it sounds less bright as you lose the resonant boost. Even Seymour Duncan recognizes this, as I have pointed out several times.

This is why you need to understand the theory, make measurements, and listen. Otherwise you do not know what is going on.

In any case, a 6000 turn pickup can have its resonance pretty much where I want, either by using the right length cable into an amp, or correct shunt capacitance into a high Z input buffer. Resonances from 2500 Hz up to about 4500 Hz make differences that are easily heard if they are altered a bit give very useful sounds on a clean instrument. I will put the resonance where it sounds good for the bass under test, and we shall see what the differences are.

The whole point of this is a 20K pickup should be very muddy, but that is not the case with the Wal pickup.

You have made a rather general claim that individual coils sound brighter than a single large one. I am investigating if this might be so and why, and will show results in a specific case. You can back off on the generality all you want, and dispargae what I do, but it does not matter.

[David Schwab]

You have made a rather general claim that individual coils sound brighter than a single large one. I am investigating if this might be so and why, and will show results in a specific case. You can back off on the generality all you want, and dispargae what I do, but it does not matter.

This is the test; Wind a humbucker with 42 gauge wire where both coils read 10k each, wire them in series and then tell me how it sounds. Then wind eight coils with 10,000 turns each, wire them in series and tell me how it sounds.

Now explain why they sound different.

Your test has nothing to do with this pickup.

And Mike, I understand why a pickup with few turns has a high resonant frequency. You are still ignoring the fact that if you wind enough wire on a pickup you will indeed lose high frequency response. Right after the resonant peak the highs start rolling off. Get enough wire on a coil and you won't get it to be bright no matter how hard you try.

[Mike Sulzer]

Who are you to tell me what the test is? I will decide what is the right thing to test, and do it. You want to do the test your way and show the results, fine. But you are not going to do that, are you?

You made the claim more general by bringing up pickups with lower resistance. Are you taking that back now? You can, you know. But just ignoring it is wrong.

And what about this statement: "A low wind pickup regardless of how many coils is going to sound bright." It shows an incomplete understanding. Is that no longer part of what you are claiming? Are refusing to deal with that, too?

By the way, there is a reason why the series connected individual coils can be brighter than one large one, but I do not think 10,000 ohms gives enough turns for it to apply. If you really understand pickups and resonant circuits, you know what it is. Can you tell me? Hint: you started this whole thing by quoting Bartolini on the lower inductance of smaller coils. There is another factor involved.

"You are still ignoring the fact that if you wind enough wire on a pickup you will indeed lose high frequency response." No, I am certainly not ignoring that. But you might be ignoring what else is involved.

This is the test; Wind a humbucker with 42 gauge wire where both coils read 10k each, wire them in series and then tell me how it sounds. Then wind eight coils with 10,000 turns each, wire them in series and tell me how it sounds.

Now explain why they sound different.

Your test has nothing to do with this pickup.

And Mike, I understand why a pickup with few turns has a high resonant frequency. You are still ignoring the fact that if you wind enough wire on a pickup you will indeed lose high frequency response. Right after the resonant peak the highs start rolling off. Get enough wire on a coil and you won't get it to be bright no matter how hard you try.

[David Schwab]

Who are you to tell me what the test is? I will decide what is the right thing to test, and do it. You want to do the test your way and show the results, fine. But you are not going to do that, are you?

Me? I wind pickups every day, what do you do? Your test in flawed because you can't possible get a muddy sounding dual coil pickup your way. Making two pickups with lower winds will make two bright sounding pickups. That's conformation bias. I've already done this test in the process of trying out new pickup ideas, and so have others. How many 10k+ pickups have you wound? Designs like this came about because the tradeoff between trying to get a loud pickup that isn't muddy. We were discussing this particular pickup, but you want to alter the specs to make it fit your outcome.

Mike, you aren't a pickup maker, and seem out of touch with some of the designs that have been on the market for years. Being pedantic only goes so far when you aren't actually trying out different pickup designs.

This is why people give you a hard time here. But it has to be us and not you, right? Maybe we need to "think about it the right way"?