Wal style pickups AND question about winders

[Triad]

Hello! I have a doubt...
I know for sure that Wal basses have special pickups... every pole magnet has its own bobbin so for a 4 strings pickup there are 8 bobbins (I guess they're wired in series).

I've owned several Wals and didn't notice a very particular sound without the preamp tweaked. So the question is (for the ones who tried this solution): more smaller bobbins give a darker sound? What's the difference for the ear?
I'm asking 'cause I have to wire a couple of huge humbuckers and I'm looking for a solution. The bobbins would be very long and I'm worried... too much weight could damage my winder AND I don't know if I'd be able to keep the wire with the right tension without breaking it (every turn would take a lot of wire so I'd have to feed the bobbin very fast). Thanx in advance!

[belwar]

Originally Posted by Triad

Hello! I have a doubt...
I know for sure that Wal basses have special pickups... every pole magnet has its own bobbin so for a 4 strings pickup there are 8 bobbins (I guess they're wired in series).

Correct... On the older Wal (The Pro basses) the top row of coils were wired together in series, then the bottom row were wired in series, then the two rows were connected together in series as well (End lead to End lead). The Modern ones such as the MKII and MKIII have the two coils for EACH STRING in series, and they are then added at the pre-amp.

Originally Posted by Triad

I've owned several Wals and didn't notice a very particular sound without the preamp tweaked. So the question is (for the ones who tried this solution): more smaller bobbins give a darker sound? What's the difference for the ear?

Thats the million dollar question. I'm building a Wal based pickup right now.. I cant comment on what the changes would be, because frankly I lack the skill to determine that without testing.. However I have some opinions..

- Having individual coils, puts more wire closer to the pole piece and the magnetic field. This should in theory increase the treble.

- If I understand it correctly, one of the factors that alters Inductance is increasing the number of turns of wire around an inductor. The wal pickup has very high inductance. Of course it also has 80,000 turns of wire. Altering the inductance is going to alter the tone. Though im still experimenting to determin its effect.

Originally Posted by Triad

I'm asking 'cause I have to wire a couple of huge humbuckers and I'm looking for a solution. The bobbins would be very long and I'm worried... too much weight could damage my winder AND I don't know if I'd be able to keep the wire with the right tension without breaking it (every turn would take a lot of wire so I'd have to feed the bobbin very fast). Thanx in advance!

Individual coils would certainly be a solution, and probably a good one too. I assuming your winding some something like an 8 string bass? If you wind slow you shouldn't have a problem with weight. You're still probably talking no more than a 1/4 pound. You could also create a split coil bucker, a-la P-Bass, but makybe with 4 coils. You could also increase the wire gauge to 43 or 44 and wind less. When you wind you could use multiple pieces of felt for tension.. each one with just a tinch of tension on it. that should smooth out the whiplash of the wire... and again wind slooooww.

[Triad]

I have to build two... well... two ELEVEN STRINGS basses
They're ready for the pickups and I'm trying to find the best solution.
With individual string humbuckers (two poles for each strings) I was thinking to wire them all in series (the basses will be passive), 5 pairs with North Up and 6 pairs with South up - to achieve hum cancelling.
Wasn't series wiring END to START? END to END wasn't for parallel?

[belwar]

Here i'll try to explain it this way.In the case of the Wal Pro Bass, the top four coils were put in series together.. For the sake of expediancy I'll refer to the Start Wire as "S" and the End Wire as "E".. If I say "E2" I mean the "End Wire of Coil 2"

The rows are wired like this... a Dash represents a soldered connection

S1 E1-S2 E2-S3 E3-S4 E4

S5 E5-S6 E6-S7 E7-S8 E8

That effectively makes two coils wound in series. They are then connected in series again with a connection between E4 and E8. Making the coils reverse wound.

Does that help?

[Triad]

Sure... thanx
So you think that two huge bobbins with 11 magnets could be wound without destroying my small Schatten winder?
Soundwise... I guess 11 small bobbins in series are gonna sound pretty different from two large bobbins... but I'd use the same number of turns. Example? 11 bobbins with 6000 turns each or two large bobbins with 11 magnets and 6000 turns each.

[belwar]

Can you post a picture of your winder?

Can you wind the pickup WITHOUT the magnet in?

[David King]

Originally Posted by Triad

I have to build two... well... two ELEVEN STRINGS basses
They're ready for the pickups and I'm trying to find the best solution.
5 pairs with North Up and 6 pairs with South up - to achieve hum canceling.

That won't do it but you can just add a dummy coil with an un-magnetized magnet inside the bass that's aligned in the same orientation so you have 6 + 6.

For the long bobbins, just remove the pulley on the Schatten motor and let the belt run right on the motor shaft, that will slow it down and give it more torque.

I guess I can't see why the length of wire is going to be that different whether you wind 11 individual coils vs one long one.I also don't see how the inductance is going to change substantially since the same quantity of magnetic material is enclosed within the same number of turns. (Joe?)

I agree that more of the wire will be closer to the magnets in the single string version and that should make them brighter over all but with only 6 K turns you might not hear the difference.

[Triad]

The winder is pretty close to the one actually sold by Stewmac... but it's older.
How could I wind the bobbin without the magnets in? I guess that, if I found a way to do it, puttin the magnets inside could be challenging.

[Triad]

They must always be in pairs (one North and one South) for hum cancelling?

[David King]

Originally Posted by Triad

They must always be in pairs (one North and one South) for hum cancelling?

Well not strictly;
A) You could wind 18% more turns on the 5 North than on the 6 South.

B) The 5 North could use larger magnets (perhaps best for larger strings anyway) and the coils could then cover 18% more area than the 6 South coils. (I think you'd want the 5 large magnets to weigh in about as much as the 6 smaller magnets.)

[David King]

Originally Posted by Triad

The winder is pretty close to the one actually sold by Stewmac... but it's older.
How could I wind the bobbin without the magnets in? I guess that, if I found a way to do it, puttin the magnets inside could be challenging.

You could find some rigid thin-walled tubing that the magnets fit perfectly into. Build your bobbin around the tubing as spacers between the flatwork. And then insert the magnets in after you've wound the coils.

Alternatively you could make dummy slugs out of acetal (delrin)® and then pop them out one at a time and replace them with the magnet.

[Triad]

Understood... but this is for a 5+6 configuration, right?
If I'm going to use 11 bobbins, one for string, and want to wire them in series and achieve hum cancelling... can I put (for example) 5 pairs with North up and 5 pairs with South up?

[David Schwab]

There are very simple ways to make the bobbins using off the shelf parts. Here's one way. Hint, think nylon.



Regarding smaller coils. In the Bartolini patent #3983778, he states:

Above the resonant frequency, the impedance is influenced by the capacitive effects between turns of the coil and between layers in the coil winding. Specifically, the changing current in one turn of the coil influences the current in the neighboring turns of the coil. This effect becomes larger with increasing frequency such that the coil behaves as a capacitive reactance with turn-to-turn capacitive leakage to ground. Accordingly, the output signal from the sensing coils falls off rapidly above the self-resonant frequency.

Since both the inductance and capacitance of a sensing coil vary linearly with its mean radius, replacing one coil by multiple small coils can reduce the impedance of the pickup system by a factor equal to the number of coils and raise the self-resonant frequency by a factor equal to the square root of the number of coils.

He wasn't the first to use this either. For bass pickups, Gibson had this:



And Ovation had the Magnum. That bass was way ahead of its time.

[Triad]

Nice!
So if I don't want to use full lenght bobbins I guess I could definitely use smaller solutions.

Is this solution ok? 11 bobbins, 2 magnets each, 1 bobbin for string. 5 North and 6 south. Would they cancel hum?
Alternatively I could use bigger magnets using the same layout of the Ovation, more or less. But should I have the same number of magnets North and South to cancel hum? I guess not... but not sure.

[mkat]

Originally Posted by David Schwab

And Ovation had the Magnum. That bass was way ahead of its time.

I bought an Ovation Magnum bass many moons ago and could never get a sound I liked out it, it was terrible IMO. I remember the neck felt ok but the thing just sounded bad. I ended up selling to help fund a 67 pbass.

[David Schwab]

Originally Posted by mkat

I bought an Ovation Magnum bass many moons ago and could never get a sound I liked out it, it was terrible IMO. I remember the neck felt ok but the thing just sounded bad. I ended up selling to help fund a 67 pbass.

Well it certainly didn't sound like a P bass. It was more in the Rick camp.

I tried out a Magnum II with the EQ circuit when they first came out. I was very impressed with it... it sounded like a piano. I didn't realize it at the time, but that was my first experience with a graphite reinforced neck.

[Triad]

You guys are leaving me aloooooone with my problem!

[David Schwab]

No, we are giving you ideas to solve the problem.

If you have an odd number of strings, and you are only doing one coil per string, then you need to add an extra coil. The magnet is not important, because there is no string over that coil. A steel core would suffice.

You can also split up the pickup into two units like a long P bass pickup.

[Triad]

So the options are:

11 coils wired around 11 magnets + a dummy coil to cancel hum (so the coils must be in pair, as I thought)

two coils, one with 6 and one with 5 magnets... and I'd put more wire on the smaller one to achieve a similar value

two coils with 11 magnets (hoping my winder doesn't die)

11 coils with 2 magnets each (but I'd need a dummy coil anyway)

Right?

[David Schwab]

Originally Posted by Triad

11 coils with 2 magnets each (but I'd need a dummy coil anyway)

You can't have two different polarity magnets in one coil.

Your winder should be fine with long coils. I have the same winder.

[Triad]

Sure, I didn't plan to put N and S magnets in the same coil... I wanted to put 5 pairs N and 6 pairs S PLUS a dummy coil. But if you think the winder won't break I'll make two long bobbins and solve the problem

[David King]

Triad,
I think there is another option which I described above..
As long as the 5 coils match the 6 other coils in area inside the coils and match the mass of magnetic material inside the coils you *might* be OK. This is purely theoretical...

[Triad]

Thanx David. By the way, I've always loved your basses
I'll see what tomorrow will bring... maybe I'll simply wind two huge bobbins.

[Joe Gwinn]

Originally Posted by David King

Triad,
I think there is another option which I described above..
As long as the 5 coils match the 6 other coils in area inside the coils and match the mass of magnetic material inside the coils you *might* be OK. This is purely theoretical...

I would modify this a bit. What one must match is the sum of the area-turns products of the 5 coils to that of the 6 coils. If a coil has a slug core, its area-turns product is increased by a factor of about three. If a coil has a magnet core, the effect on area turns product will be small. In both cases, experimentation is needed, as the exact area-turns products and increase factors are hard to predict from theory.

[Triad]

Uhm... I use magnets poles, not bars and slugs.

[mkat]

Originally Posted by David Schwab

Well it certainly didn't sound like a P bass. It was more in the Rick camp.

Yeah, sure was. I was much more comfortable with the pbass sound at the time, but I did like the Rick sound better than the Magnum.

Originally Posted by David Schwab

I tried out a Magnum II with the EQ circuit when they first came out. I was very impressed with it... it sounded like a piano. I didn't realize it at the time, but that was my first experience with a graphite reinforced neck.

That's interesting, I think the active eq on this would be more to my liking. The documentation states that the bridge pickup in both I and II produces a piano like tone, but I didn't hear that in the one I had (Magnum I).

[Triad]

I ended up making the pickups in the good ol' way: two bobbins. They turned out huge but they work and even if they were a bit hard to wound now they're ok and ready to pot

[Mike Sulzer]

If you replace a single coil pickup with n coils, putting the same number of turns on each coil, you can expect the inductance of each of the n coils to be about 1/n times the inductance of the single coil. So if you put the n coils in series you get the same inductance as the single coil.

The capacitance of each of the n coils is lower than that of the single coil as well. So the resonance frequency with the n coils is higher than for the single coil. But this ignores the cable capacitance, which is larger than the the capacitance of the single coil pickup. So if you use the pickup without a preamp, using the n coils makes some, but not a lot, of difference to the resonant frequency of the system with the cable. This is because the the cable capacitance is larger, and therefore more important, than the pickup capacitance.

If you use a preamp, thus unloading the cable capacitance from the coils, then the resonant frequencies of both systems are increased, and that of the n coil pickup is very high. But the resonance of the single coil might be as high as you need in this case.

[Triad]

Both basses are passive...
I would have liked to try to make more smaller coils but I did fear to do something wrong about hum cancelling so I went for the "standard" pair of huge singles.