Should all pole pieces have the same polarity?

[pocketgroove]

Hi,

I've been working on an instrument, and for a while, something has just sounded "off"about it. Out of curiosity, I touched a strong magnet to each individual pole piece to see if they had the same polarity. Two of them (numbers 1 and 3) repelled the side of the magnet that all the others had attracted.

So, is this normal? Or should the pole pieces all have the same polarity? If so, can it change over time, or was there probably something wrong with the pickup from the factory?

Thanks!

[GlennW]

Not normal.

All the pole pieces for the same coil should have the same polarity.
Single coils; SCPB, Strat, Jazz Bass, etc...yes, all the same.
HB pickups; 1/2 & 1/2, one coil should be all N, the other all S
Split P; one coil all N, the other all S

Change over time? Not on their own (I think).

Something wrong with the pickup at the factory? It was probably a minor mix up.

[walterw]

Originally Posted by pocketgroove

Hi,

I've been working on an instrument...

specifics, please; what is it?

[sawzalot]

The answer is that it depends. For example, Bartolini used to make a set of Jazz pickups where each string had its own coil and pole piece, and each was reverse-polarity/reverse wound. The design made them hum-cancelling within each individual pickup. If used in pairs, they could only be used with another of the same pickup design or else every other string would be out of phase and have no bottom end.

I wouldn't be surprised if there were other pickups out there using the same sort of design, which would result in each polepiece being reverse polarity.

Tom

[Stealth]

There's also the possibility it's an inline humbucker, basically a split-coil design in a Jazz housing or similar, without the offset coils. Still, the polepieces would've been NN NN NN NN SS SS SS SS (or N N S S).

[SGD Lutherie]

Originally Posted by pocketgroove

Out of curiosity, I touched a strong magnet to each individual pole piece ...

That's a good way to ruin your pickup too. If you are using a ceramic or neo magnet to touch an alnico pole, you will demagnetize the alnico magnet.

And as the others have asked, what kind of pickups are they?

If it's a single coil like a Jazz, they should all be the same. But if it has multiple coils it might be intentional.