Jazzbass 5 string

[Evilbiker]

Iīm about to wind a splitcoil 5 string jazzbass and my question is do i wind say 9000 windings on a singlecoil how much do i wind on each coil! I have wind a splitcoil to a 4 string and thats easy because thay have the same size on the coils, but for a 5 string the coils is not same size!
Thanks

[David Schwab]

Wind the same number of turns on each coil, even though they aren't the same size.

[Peter Naglitsch]

For split coil pickups you wind exactly the same number of turns on both of the smaller coils ans you would do on the original "non split" version of the same pickup. So if a traditional J-bass pickup have 9000 turns (I don't wind that type of pickup so I don't have the numbers in fresh memory, please check them) you wind 9000 turns on the "south" coil and 9000 turns on the "north" coil (north and south reffering to the polarity of the mangets). And yeas, it will give you a higher DVC recistance reading than the non-split J-bass pickup but that is part of the split pickup nature.

Edit: David beat me to it

[David Schwab]

I would divide the 9,000 turns of the original, so it would be 4,500 on each coil, wired in series. That's how the commercial split Jazz pickups are done. If you do 9,000 turns on each coil, it will sound more like a P bass, and not a Jazz.

[David King]

I don't think this will work out as well as hoped since the coils, being different lengths will cover different areas. The longer coil should have fewer turns and stronger or longer magnets to keep the levels the same AND cancel hum effectively.

If you didn't care too much about the hum, which will be slight, then wind the same number of turns and let it go at that.

Calculating the actual numbers of turns needed involves a lot more math and physics than I possess so I'm planning on going at it via hit-or-miss until I get close enough.

[David Schwab]

David, the commercial pickups like this wind the same number of turns on the two different size bobbins. It's the turns that matters for hum cancelation.

But as you mentioned, you can offset the coils and still have a quiet pickup. I've offset humbuckers by 1,000 turns and they didn't get noisy at all.

I'd also place the wider coil under the treble strings. Just seems like it would balance better that way.

[Evilbiker]

Thanks guys! Iīm about to wind the pickup soon, i have done the bobbins and gonna press in the magnet today, then is just the winding left!

[Joe Gwinn]

David, the commercial pickups like this wind the same number of turns on the two different size bobbins. It's the turns that matters for hum cancelation.

If the coils are of different sizes, one may need to adjust the turns counts to achieve full cancellation. Not that it's terribly fussy to get adequate cancellation.

In any case, if there is no iron nearby, the area-turns products of the two coils must match for perfect cancellation.

With iron, it gets more complex, and lab measurements will be quicker than theory.

But as you mentioned, you can offset the coils and still have a quiet pickup. I've offset humbuckers by 1,000 turns and they didn't get noisy at all.

There was a long thread on the theory underlying this. As I recall the equation, assuming each coil is nominally 5000 turns, a 1000 turn difference yields 4500 turns and 5500 turns, and a cancellation voltage ratio of (5500-4500)/(5500+4500)= 0.1, or 20*Log(0.1)= -20 dB, or 20 dB cancellation, which is sufficient in practice.

I'd also place the wider coil under the treble strings. Just seems like it would balance better that way.

Why?

[David King]

David Schwabe,
I have examined a lot of "commercial" noiseless split coil J pickups and they all seem to have the normal number of turns around each coil though they are most often wound in 43 awg so it looks like less wire but the of course the DCR goes up with the higher resistance per foot.

The proposed 4500 turns on such a short coil gives a very low DCR. I just wound some split 4 string J coils and 8500 turns barely got me 3.1K
That's only 6.2K in series which is very low for a Jazz pickup, they sounded a bit puny to boot. The problem of course is that 9000 turns of 42 awg will never fit on a 5 string PU in a 4 string PU shell unless the magnets are closer together and longer and the thinner flatwork is used

Joe, thanks for the Turns x Area formula, I figured it would be something very simple like that. I can't remember if Alnico acts like an iron core to some extent or not at all. The easy solution is to add a couple of uncharged magnets to the shorter coil to even up the ferrous content. You see this a lot on 5 string P pickups where there's plenty of room for equal coil lengths under the covers.

[Joe Gwinn]

Joe, thanks for the Turns x Area formula, I figured it would be something very simple like that. I can't remember if Alnico acts like an iron core to some extent or not at all. The easy solution is to add a couple of uncharged magnets to the shorter coil to even up the ferrous content. You see this a lot on 5 string P pickups where there's plenty of room for equal coil lengths under the covers.

Alnico has an incremental permeability of 3 to 5, so alnico is almost air. Mild steel is more like 2,000. Ceramic is almost exactly 1.00, so it is equivalent to air.

[David Schwab]

Why?

I don't do many split coal pickups, but I like them better when the bass half is closer to the bridge, which is opposite from the way Fender did it. You don't hear the tonal change as much going from one half of the pickup to the other.

I really hear it on a standard P bass, and it bugs me.

So if I were going to do that with an odd number of strings, I'd have the top three strings on the coil closer to the neck.

[David Schwab]

David Schwabe,

Hey.... watch that "E", Kinge!

I have examined a lot of "commercial" noiseless split coil J pickups and they all seem to have the normal number of turns around each coil though they are most often wound in 43 awg so it looks like less wire but the of course the DCR goes up with the higher resistance per foot.

The proposed 4500 turns on such a short coil gives a very low DCR. I just wound some split 4 string J coils and 8500 turns barely got me 3.1K
That's only 6.2K in series which is very low for a Jazz pickup, they sounded a bit puny to boot. The problem of course is that 9000 turns of 42 awg will never fit on a 5 string PU in a 4 string PU shell unless the magnets are closer together and longer and the thinner flatwork is used

After I posted that (and while the forum was down) I thought about the smaller coils I'm winding for a Wal pickup clone.. each coil holds 9,000 turns of 42, but they only measure about 3K.

So yeah, I'm probably mistaken when I said that. I can see why they would need to wind the regular amount on the coils. But that's the way I thought it was done.

I have an 80's Jackson P/J bass here for some work, and it has a split coil Jazz pickup. It's potted with epoxy, so I can't look inside, but interestingly it's quite a bit taller than a regular Jazz pickup... almost twice as tall. So they are probably using 42 AWG. I don't know if the coils are in series, but it sounds like it. It measures 11.94K.

[David King]

Hey.... watch that "E", Kinge!

Oops! Sorry David, have I been doing that for years? I have no idea where that came from. Very embarrassing I tell you. Anyway they always called me "Queeny" in Jr High.

[David Schwab]

Oops! Sorry David, have I been doing that for years? I have no idea where that came from. Very embarrassing I tell you. Anyway they always called me "Queeny" in Jr High.

Hey no problem! It is a version of the name though.

Yeah, I was "Schwaby".

[Joe Gwinn]

Yeah, I was "Schwaby".

It should be a form of swabbie for sure. The context is holystone.