Bass HB / Guitar HB construction specs

[Biarnel]

There is something that leaves me with a face like this:

If you want a good bass humbucker (or call it split coil, anyway something hum cancelling), you have to:
Wind a coil.
Wind another coil, reverse magnet polarity.
Connect the starting wires of the coil together.
Use one of the finishing wires as the HOT, the other one as GROUND (by the way: WHICH one?? it's the same?)

If you want a guitar humbucker, let's say PAF style, accordingly to stewmac's free info, you have to:
Wind a coil: this coil has polepieces touching the alnico bar underneath.
Wind another coil, same wound, same number of turns.
Solder the adjustable coil start to GROUND, adj. coil finish to slug coil finish, slug coil start to HOT, slug coil finish to adj. coil finish.

Well this seems quite different to me.
The bass style has polepieces in both coils. The wiring also differs.

And again, why the slug coil, not wired to the adj. one (think to 4-conductor wire), routed directly to the output, will make the guitar play even if there are no mags inside?

[Phil m]

1. It doesn't matter which one you use for hot or ground. they are interchangeable.

2. The wiring is the same. However, you've confused me with this sentence

Solder the adjustable coil start to GROUND, adj. coil finish to slug coil finish, slug coil start to HOT, slug coil finish to adj. coil finish.

Everything is normal to me and results in a normal series humbucker until "HOT". By adding "slug coil finish to adj. coil finish." you're losing me

3. The bar magnet under the guitar humbucker magnetises both coils through the slugs /screws. One is polarized south, the other north.

[Biarnel]

adj. coil finish to slug coil finish, slug coil finish to adj. coil finish.

Sorry, I just mentioned the same connection twice

Anyway, if you examine this:

..you will notice that screw poles are magnetically "attached" to the alnico via the metal spacer, while the slugs are somewhat saparated by the plastic shim.
Ok, mag field will reach them anyway, but in a different way.
Why a plastic shim instead of a metal one?

[Phil m]

I'm a bass builder, not a guitar builder so I might not be totally right on this one but (correct me anyone if I'm wrong) I believe the slugs are directly in contact with the right side of the magnets. i.e. they are wedged between the bar magnet and the plastic spacers.

[mkat]

Sorry, I just mentioned the same connection twice

Anyway, if you examine this:
..you will notice that screw poles are magnetically "attached" to the alnico via the metal spacer, while the slugs are somewhat saparated by the plastic shim.
Ok, mag field will reach them anyway, but in a different way.
Why a plastic shim instead of a metal one?

I'm a bass player too, but I do play some guitar which doesn't necessarily mean much really. I don't see what the difference is though. Whether a humbucker has a single bar magnet with slugs and screws and other parts, or individual alnico magnets - the magnetic polarity of one coil will be south the other north. You still wire them up the same. It just so happens that the dual coil bass pickups I've been making look drastically different to the guitar humbucker pic you attached. Correct me if I'm wrong, but the polarity, winding direction and hookup is based on the same principle.

[David Schwab]

The slugs on a PAF style humbucker are active, and in fact that coil has more output than the screw coil. The adjustable screws were not in the original design, and were added as a marketing decision, since the P-90 had adjustable poles, and Fender's don't.

You can make a humbucker with both coils exactly the same. Bass pickups are different because unless it's a Fender copy, they are newer designs. They don't have to copy 50 year old Gibson designs.

I make bass humbuckers with a blade polepiece in each coil.

And since we are on the subject, I started on guitar first, but I'm a bass player. The two instruments aren't all that different. Bass guitar is just a regular guitar an octave lower after all.

(actually I started on drums first, but that's another story)

[Peter Naglitsch]

..you will notice that screw poles are magnetically "attached" to the alnico via the metal spacer, while the slugs are somewhat saparated by the plastic shim.
Ok, mag field will reach them anyway, but in a different way.
Why a plastic shim instead of a metal one?

Phil’s right. The slugs are magnetically in contact with the bar magnet and the plastic shim is placed on the other side of the slugs, just to help “balance” the coil (physically, not tone-vice or any other, deeper meaning). And as David mentioned, the slug side had a higher magnetic flux compared to the screws. That is probably because the lack of screw extending through the back helps directing the magnetic field, or the more steel in the slugs.

But on the other hand lets have a look at the DiMarzio Air Norton pickup. It has small (patented of cause, we are talking DiMarzio here) plastic holding fixtures that separate the pole pieces from the magnet to alter the magnetic field strength.

The reason to why the P-bass pickup is different is that Leo (Fender that is) tried to go around Gibson’s patent for the humbucker. And as with every thing he designed he tried to make it possible to manufacture the stuff as cheap as possible in large quantities.

[Biarnel]

Everything is clearer now.
I suppose I had a bit of confusion in my head - I really need to say thanks to everyone in this forum.

Now, if it's not asking too much, is there in the net a vademecum for coil playing?
I mean... you do this and you cancel hum, do that and you cancel the sound too, do this and you are in phase, do that and you have the ultimate pickup..
Something to use as a quick reference, when building PUs with more than one coil (I heard music man bass PU has 3 coils... how come?).

[Phil m]

I'm not sure what a vademecum is. Do you mean somewhere to find wiring diagrams?

Here's a link to Seymour Duncan's schematic page. They've got diagrams for dozens of combinations.
http://www.seymourduncan.com/support/schematics.shtml

[GlennW]

Vademecum? If it was mademecum I'd think I walked into a porn site.

[Biarnel]

Sorry, it's latin
Vade-me-cum (travel with me) it's more or less what you call and handbook.

I was talking about a quick reference for coupling coils, not just wiring pickups.

[madialex]

Vademecum? If it was mademecum I'd think I walked into a porn site.

[David Schwab]

I heard music man bass PU has 3 coils... how come?

They have a switch to choose either the two top coils, wired like a regular humbucker, or one of the top coils plus a bottom coil for hum cancelation to give a single coil sound.

[Biarnel]

You mean that the bottom coil (with mags? without mags?), in series with one of th top coil, will cancel the hum while leaving the classic single coil sound? Or maybe it's boosted like an HB but less muddy?

And again: the bottom coil is in series with one top coil only? Maybe is two top series, two top parallel and bottom series, one top in series with bottom?

[David Schwab]

You mean that the bottom coil (with mags? without mags?), in series with one of th top coil, will cancel the hum while leaving the classic single coil sound? Or maybe it's boosted like an HB but less muddy?

And again: the bottom coil is in series with one top coil only? Maybe is two top series, two top parallel and bottom series, one top in series with bottom?

It's three coils, but only two are used for a humbucker. The third coil is under the other two, and is used for hum cancelation when the pickup is switched to single coil mode.

It's a dummy coil. I'm not sure exactly how it's made, but I wold assume it has pole pieces but no magnets.

Some music man pickups are wired in parallel. I'm not sure how the dummy coil is wired.

Bartolini does a pickup like this also, but I think his dummy coil is between the other two.

Here's a photo of the Nordstrand version.