5 string p bass pickup

[rjb]

I wouldn't use neo rods though. Too much string pull. Alnico is bad enough.

I guess I didn't clearly make my point.
Please reference posts 4, 5, & 6

Post 4:
David King says the unmagnetized dummy slugs should have the same permeability as the magnetized poles- but he mis-remembers that AlNiCo has permeability close to air (i.e. relative permeability close to 1).

Post 5:
So Marko concludes that he should use plastic slugs.

Post 6:
I clumsily point out that neodymium has a relative permeability of 1, and AlNiCo has some higher permeability.

I didn't follow through and state what I thought was the obvious conclusion:
1) Since you are probably using AlNiCo magnetic poles, then use unmagnetized AlNiCo slugs.
2) If, for some reason, you are using neodymium poles, then use plastic slugs.

But yes, I would expect neo rods to be too strong for bass pickups.

EDIT:
This is all water under the bridge.
Marko has already built his 5-string P & split-J set, and they sound great.

[David Schwab]

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.

I wouldn't use neo rods though. Too much string pull. Alnico is bad enough.

[Marko Ursin]

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

That's right.

[big_teee]

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

[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?

[David King]

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

[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]

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]

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]

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]

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.

[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

[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.

[Marko Ursin]

In that case I'll use plastic.

[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...