New hum cancelling widget: Xotic HRI

[big_teee]

I think the permeability of Alnico is a few times air, that is, low compared to steel, but enough to matter in achieving balance.

I am thinking of two windings rather than two completely separate coils as I believe your are.

But the key thing in order to avoid affect on the sound is low inductance. The typical approach is a large air coil coil with many fewer turns than a pickup (Suhr): low inductance, but similar sensitivity to hum as the pickup. But that is not what they are doing here. Another approach might be a larger magnetic core than extends as nearly as possible through the entire thickness of the bass and has as big a diameter as you can fit in. Maybe that is what they are doing. I did not see anything about electronics, so this is passive?

Thanks David, Mike:
Without getting too complicated, and trying to stay on a similar design like the Video.
I like the idea of 2 smaller stacked coils.
It would be easier to keep them the same size, and same DCR.
So just for experimental purposes.
Take 2 slug humbucker coils and wind them the same, Stack them, and run unmagnetized Alnico rods thru them.
Then the center tap like david suggested could be the 2 starts or 2 finishes of the 2 coils with the rods in the middle.
Could something like that be used for an experiment?
Thanks,
Terry

[Mike Sulzer]

Bass players do not seem opposed to active circuits. It is much easier to get good cancellation and minimal effect on the sound with an active circuit. It is also easier to design the coil since you can pretty much just duplicate the pickup.

Thanks David, Mike:
Without getting too complicated, and trying to stay on a similar design like the Video.
I like the idea of 2 smaller stacked coils.
It would be easier to keep them the same size, and same DCR.
So just for experimental purposes.
Take 2 slug humbucker coils and wind them the same, Stack them, and run unmagnetized Alnico rods thru them.
Then the center tap like david suggested could be the 2 starts or 2 finishes of the 2 coils with the rods in the middle.
Could something like that be used for an experiment?
Thanks,
Terry

[big_teee]

i Did some experimenting, and didn't have much luck.
I just had a single coil and a slug coil wired in series loose to a input jack.
It was all pretty noisy.
T