Humbucker question

[chansencc]

This was partially answered, but at the advise of one respondent I am reposting this question here.



I have looked quite extensively, but I can't seem to find the answer to my question... perhaps I not looking in the right places. Why do some humbucker pickups have screws for the second bobbin while others have magnets on both rows.

The first pic is of a bassline p/u the second is just the stewmac diagram of their kit. is the Bassline still technically a humbucker or are the two coils wired differently? Series vs. Parallel?


Thanks! I'm quite new to this but I really did try to find the answers first!

Christian

[roundmidnight]

There are many different construction approaches to humbucking designs.
1). Iron slugs in each coil with a bar magnet under the coils (appears to be the original Seth Lover design)
2). Rod magnets in each coil (some bass pickups and guitar variants)
3). Bar magnets inside each coil (Firebird)
4). Adjustable screws in one coil with iron slugs in the other with a bar magnet under the coils (typical PAF and many variants)
5). Adjustable screws in both coils with a bar magnet under the coils (Gretsch Filtertrons)
....etc.

As long as the coils are connected in series with reverse winding direction and reverse magnetic polarity and identical number of winds you obtain hum cancellation which was the original intent (har, har, as far as I know).

Get a copy of Dave Hunter's pickup book, it is a good start.

[belwar]

Hi there,

In a standard humbucker there is one magnet that is located below and between the two bobbins. The side faces of the magnet are then in contact with a pole piece. These pole pieces can either be screws, set screws, or soft iron slugs. The pole pieces touching the north face of the magnet create the north coil, and the pole pieces touching the south side of the magnet create the south coil.

So why is it most common to see one screw side and one slug side?

Tradition and marketing. In the early 1950's, Gibson was using "adjustable pole pieces" a major selling point in the advertisements of thier guitars. The P-90's that were installed OEM on the early les pauls has adjustable screws. When Seth Lover came up with the design for the Humbucker, he didnt use screws at all, only two rows of slugs. The patent shows this design too - No screws anywhere. However when it came to the production models (The famed P.A.F. pickups) Gibson couldnt very well turns its back on all the marketing it had just done explaining why "adjustable pole pieces" were better. So Seth Lovers original design was slightly altered to include a row of pole screws.

A PAF style humbuckers is by nature always pole screws on one side, and slugs on the other. Traditionally the screw side is the south side of the magnet. In the neck position the screws are closest to end of the fretboard, and in the bridge the screws are closest to the bridge.

Hope that helps,

b.

[David Schwab]

The first pic is of a bassline p/u the second is just the stewmac diagram of their kit. is the Bassline still technically a humbucker or are the two coils wired differently? Series vs. Parallel?

As long as you have two coils wired so that it hum cancels, then its a humbucker. They can also be stacked on top of each other, or in a split coil arrangement like a P bass.

It doesn't matter if the coils are wired in series or parallel.

Music Man pickups are often wired in parallel, but you can wire them both ways.

[chansencc]

Thanks all for the info! I didn't realize there were so many types of humbuckers, or even how the name played into the intention of it.

I am really impressed with the amount of info here - I hope to put it to good use when I finally make it to my next project which will be a neck through bass.

I will be sure to pick up the book that was suggested.

Thanks!

Christian

[David Schwab]

Thanks all for the info! I didn't realize there were so many types of humbuckers, or even how the name played into the intention of it.

They "buck" the "hum" so that's what the name means.

[Bob Entooler]

The David Hunter Book, How to find the sounds you like(?) is available at Barns and Nobel. My girlfriend just grabbed me a revised edition today on her lunch break. Yes she has sisters but they are married.