aluminium bobbins

[Seasick Mick]

I want to make a few single string diddley bow pickups with sewing machine bobbins.Would it be ok to use aluminium bobbins?....

[ILL GREEN]

Bobbins should be non-conductive. Wood or acrylic thin boards around 1/8" or 3/16" would be recommended. Or any  non-conductive material, even a vinyl record.

Coils need to be suspended, if you used aluminum, you can fry the whole shebang.

=D actually, you'll get nasty feedback, louder and worser than the 60 cycle hum.

[Seasick Mick]

Thank you.That's what I suspected,,,,

[François]

Just do like I did. Crack open an old wall wart, extract the transformer and use that as the coil.

You can then hide it in the bow and use a metal sewing machine bobbin for decoration on top of the coil. Just make sure there is a magnet inside the coil itself.

On my prototype 2 string bow, I have a big metal washer on top and it works just fine.

[Seasick Mick]

Thank you,Francois...

[JL]

If you are talking about using an aluminum bobbin for wrapping the coil wire of a magnetic pickup, I'd say you will get something between interesting and disappointing.  Although aluminum is not Ferromagnetic, it does have some strange interaction with moving magnetic fields reacting with an induced current with an opposing magnetic field axis. 

An AC magnet will hover over an aluminum plate. 

[Seasick Mick]

Thank you,JL.I think I will stick with making bobbins from plastic or wood...

[darryl kernaghan]

It is an interesting question, because in times gone by, we had a thread regarding so called "induction pickups", unfortunately, the object that initiated the thread had a dis agreement with someone and in a hissy fit closed his membership/ links with CBN, unfortunately due to the original initiator "owning" the thread, when he left , some 30 or 40 pages of development went as well. But, more relevant to your query is the fact that, essentially the the bobbins were a conductive material, but also the actual coil, but they needed separation/ isolation  from the magnets, I suggest that assuming you are using cylindrical magnets,a simple tube of heat shrink around them should see you ok, there is nothing I'M aware of that says the bobbin can't be alive, but, you do need separation from the mag field, of course you also have the issue where the actual winding on the bobbin needs to have a start and finish, but that is pretty easy to overcome

[Seasick Mick]

That's interesting.Perhaps I will experiment with them and see what the outcome is....

[Timothy Hunter]

i did think that the bobin would act like a primary coil and the copper windings as a secondary.. in the induction pickup the secondaries were about 500 to 1000 windings... 

even using the way back machine the induction pickup thread is gone.. sad times whem most of the thread wasnt his!

https://web.archive.org/web/20161025131400/https://cigarboxnation.c...  found some of it!!

[Seasick Mick]

I will have a good look at that...Thanks

[François]

Was just looking at the patents...That's a pretty strange arrangement that they came up with.

Lots of talk about them here https://groupdiy.com/index.php?topic=27929.0

Personally, I really don't know if the sound is worth the effort. The way it's built it reminds me a bit of those two part bass pickups where the high and low strings get recorded separately in order to enhance the tone.

I have the feeling that those lace pickups are a bit like that but in a single package with an overly complicated layout.

[darryl kernaghan]

Francois, they are remarkably simple to make in the basic form, but need a low to high impedance in line mic transformer, the Lace pickups don't require this as they have added circuitry to overcome it.