5 string p bass pickup

[Marko Ursin]

I've looked at 5 string p bass pickups and Nordstrand pickups caught my eye because they have normal sized covers, not one shorter and one longer cover which are harder to find. I suppose there is same size bobbin in both halves, the other is just made without one pair of magnets and instead it has either metal or plastic slugs. What do you think?

[David King]

Marko,
Actually they do have the 5th and 6th magnet under the cover but these aren't magnetized. It's a really easy way to achieve full hum cancelation.

[Marko Ursin]

I guess steel poles without magnets will work as well. I have to wait for the covers before drawing bobbin plates for CNC.

[David King]

Alnico has a lower permeability than iron so it makes sense to stick with identical materials though it probably won't make a huge difference. I think I've read here that AlNiCo has a permeability similar to that of air so a plastic slug might be better than a steel one...

[Marko Ursin]

In that case I'll use plastic.

[rjb]

What type of magnets are you planning to use?
Relative permeability of neodymium magnets is near 1.
A cursory Google search on alnico shows a range of values of about 1.3 thru 6.7, depending on type, conditions, and who you ask.

[big_teee]

If you want it to have P-bass tones?
Then it needs to have Alnico rods for the main poles.
Don't you think?
T

[Marko Ursin]

Wound but not tested yet as the bass is on the drawing board. I made a split coil J pickup as
well. 9500 rounds on P, 10000 rounds on J. I have to charge the magnets before testing.

[David King]

Marko,
You won't get very effective hum cancelation on the split J if the coil's turns*areas aren't the same, the shorter coil will need some additional turns to make up for the shorter coil length. With more turns it will need slightly weaker magnets to have the same output. You might try 9000 turns on the longer coil vs 12000 on the shorter one and then load the shorter one with A2 magnets while the longer one has A5s. You can also discharge the short coil's A5s by 30% or use a fatter or better yet a longer magnet (making a taller coil for the extra turns).

[Marko Ursin]

Sounds like this. I hear no problem humbucking the J so I guess this is how it's going to be. P, J and both with two a bit different settings.
Maihinnousu - Lataa - MPU - 5pj16

[David King]

It sounds quiet enough to me, maybe I'll try one after all. Did you have room to wind the J with 42awg? I'm wondering if the offset magnets helped with the bobbin space and with the magnetic cancellation at the join.

[Marko Ursin]

It sounds quiet enough to me, maybe I'll try one after all. Did you have room to wind the J with 42awg? I'm wondering if the offset magnets helped with the bobbin space and with the magnetic cancellation at the join.

I wound the J with 43awg. There was less room at the sides than at the join. It was tight to get 10000 rounds with 17mm string spacing bobbins.

[David King]

I bet it was! Now try it on 19mm in a short j shell the way Carey does.

[Jason Rodgers]

Wound but not tested yet as the bass is on the drawing board. I made a split coil J pickup as
well. 9500 rounds on P, 10000 rounds on J. I have to charge the magnets before testing.
[ATTACH=CONFIG]37896[/ATTACH]
[ATTACH=CONFIG]37897[/ATTACH]

Just to clarify: the P is actually using 3+3 bobbins, but one is only mag loaded for 2 strings, and 4750 turns on each; the J is using 3+2 bobbins, with some combo of 10,000 turns between the two?

[big_teee]

The 9500, & 10,000 turns, should be per bobbin.
T