Pickup winding question

[Steve Dallman]

I am building a 5 string, 51 Precision bass and want to wind a 5 pole, side by side, humbucking pickup. One coil will have two poles and the other 3 poles.

Do I wind the three pole coil the same as the two pole, or should the 3 pole side have 3/5th's winding compared to 2/5ths on the opposing, two pole side?

Thanks in advance.

I would also consider winding a stacked humbucker but need a little info on winding those coils.

So far the only pickup winding I've done is for repairing bad coils in pickups.

[David Schwab]

I haven't done this myself (yet) but I would imagine you want to wind both coils the same DC resistance ... it is a humbucker after all. I have seen some 5 string P bass pickups where they had a 6th pole in one coil... just for balance. I think it was just a slug.

I'm currently working on a stacked Jazz bass pickup. It's wound, but I haven't had a chance to try it out yet. I think the side by side humbuckers, like a P bass, sound better.

There's a few ways to do a stacked pickup. The difference is in the magnet arrangement. Some have opposite magnet polarity in each coil (magnets in between the coils). Some have the magnets running all the way through both coils, and some have a dummy coil on the bottom with no magnet... with/or without a metal load.

[SK66]

You are in a pinch..Besides having a "quick return" in the fields, you also have the epitome of unmatched coils. If you wind them the same you will get unequal volume but more hum cancelling, if you wind 3/5-2/5 you will get more even volume balance but less hum cancelling...My best guess is to go more towards the 3/5-2/5 and accept a little noise...also, a lower overall wind count will help minimize the issue.

[David Schwab]

This isn't a big deal. Both EMG and Bartolini make 5 string split pickups where each coil is a different size. I guarantee they wind them to the same DC resistance for hum cancelation, since they are quiet pickups.

Here's an example:

http://www.delano-pickups.com/english/5-string/pmvc5fe.html

[David Schwab]

Here's another one... this time a Jazz pickup:

http://www.nordstrandpickups.com/images/pickups/bass_trad/b-nj5fs_coveroff.jpg

[Mark Hammer]

Don't invest too much into the notion of matched resistance.

Hum-rejection is a property of matched turns and "antenna properties". The coil DC resistance is a pretty useful indicator of matched properties when the two coils are wound on identical-sized/shaped bobbins with identical wire and winding tension and the same number of turns. Once the two coils become dissimilar in one or more of those parameters, however, DCR becomes a less useful basis for matching in order to cancel hum.

I'm not saying that a 3/2 split in a pickup for a 5-string bass would NOT be capable of hum-rejection. Rather, given the dissimilar bobbin size, I think you'll get a more usable outcome if the coils are matched for #turns rather than DCR.

[David Schwab]

That makes sense. I wind by turn count myself, and only take DC resistance reads for my own info.

Aero (http://www.aeroinstrument.com/pickups.html) makes a 5 string J bass pickup with 6 magnets.

They say this on their website:

Odd string pickups have an even number of magnets (e.g. 5 string pickups have 6 magnets, the 6th unmagnetized magnet is on the high string side)

There are many paths to the same outcome! :)

[Dave Kerr]

How about using 43 gauge for x# of winds around the 3 (or 6 for JB) poles, and 42 gauge for the same # of turns around the other 2 (or 4) poles? Output should balance pretty well, and the thicker wire may compensate a bit for the reduced footprint of the smaller bobbin. Maybe using a heavier build insulation on the smaller bobbin would help, too.

[Pep]

+1 for same number of turns vs. DCR (for noise cancelling properties). Personally I would use the same guage wire. You can always compensate for volume differences with pickup height.

[Joe Gwinn]

Don't invest too much into the notion of matched resistance.

Hum-rejection is a property of matched turns and "antenna properties". The coil DC resistance is a pretty useful indicator of matched properties when the two coils are wound on identical-sized/shaped bobbins with identical wire and winding tension and the same number of turns. Once the two coils become dissimilar in one or more of those parameters, however, DCR becomes a less useful basis for matching in order to cancel hum.

I'm not saying that a 3/2 split in a pickup for a 5-string bass would NOT be capable of hum-rejection. Rather, given the dissimilar bobbin size, I think you'll get a more usable outcome if the coils are matched for #turns rather than DCR. I agree that turns count (not DC resistance) is the key.

Actually, for best hum rejection one should match by area-turns product, so the 3-pole section would get fewer turns than the 2-pole section. Assuming that the area of a "pole" (including surrounding air) is constant, the turns counts for a 3:2 split would be in the ratio 2:3 (yes, reversed, as 2:3x3:2=6:6), so the 2-pole section has 50% more turns than the 3-pole section. The wire guage is irrelevant, and need not be the same. Likewise, DC resistance.

One consequence of this is that the 2-pole section will be very slightly louder than the 3-pole section, at least in theory. Probably one can if needed simply adjust string-pole distances to compensate, as another poster suggested.