Rare Earth Magnets

[psw]

Rare Earth Magnets

These are also known as Neodymium Iron Boron.

Yes they are very powerfull and expensive - However because of this power you don't need to have magnets of the same dimension so for a similar power to alnico the cost is very competitive.

One of the major problems with pickup winding is the obtaining of suitable magnets. I live in Australia so the choices can be minimal however it is a problem everywhere as you will see on other sites on winding.

As I am more interested myself in building a better mousetrap, sorry pickup , the fact that they are so small opens up a huge range of options for new designs.

Anyway. A Rare Earth Magnet the size of a strats polepiece would suck the string down to the pickup and you might find it difficult to get off!

I've been experimenting with discs of 5mm x 1.5mm and 3mmx2mm so far. You can stack them to make even more powerfull magnet and/or attach them to various types of magnetic materials (steel, nails, rivits, staples, refrigerators, etc) to create different core shapes.

And this is the key to pickup design. It is not so much the power of the magnet but the shape of the magnetic field, and the coil within it, that creates it's sound.

Consider this. Humbucking pickups use steel slugs and screws to direct the field through the coils and towards the strings from a bar magnet below. The same is used on the cheapest single coils where you see a large ceramic magnet below. Real single coils have internal magnets and a deep coil. Why are these "better" because it is the shape of the field and the coil design that gives much to the classic strat sound.

In short : Rare earth magnets, because of their small size to power ratio means that you have new possiblities to explore in manipulating the shape of the magnetic field and the size and shape of the coil.

My experiments include moulding pole pieces from epoxy containing pure iron powder and a rare earth magnet within. This is an attempt to utilize advanced transformer principles to heighten sensitivity to changes in the electromagnetic field and to create cores in any shape I want.

I think the best advice for anyone trying to reproduce a classic pickup design is to copy it completely. However, if your up to stepping into the unknown check these out

PSW

p.s.

(we use metric down here and it's a lot easier for small dimensions even though I was brought up on feet and inches check out the stonehenge scene in spinal tap to see what can go wrong!. 5mm= about 1/4 inch

[Phil Mailloux]

Hi PSW,

Thanks for answering my questions (in LOTS of details)

I'm experimenting with pickups right now, so your info definitely gives me food for thought.

(we use metric down here and it's a lot easier for small dimensions even though I was brought up on feet and inches check out the stonehenge scene in spinal tap to see what can go wrong!. 5mm= about 1/4 inch

I'm canadian, we also use metric and imperial, so anyone is fine with me.

Just a tip: you might want to click on the "add reply" button next time to post your message instead of the "start new thread" button. It's less confusing for anyone else to follow the conversation.

[jefm]

Cool stuff on those magnets...

Definately share the results of the expiriments with us

[psw]

Thanks guys

I'll try to keep the thread.

I'm new to this chat stuff so bear with me!

psw

[ansil]

plastic sewing mahcine bobins for thread a spool of pickup wire and a sewing machine makes great pickup winders for individual type pickups.

place six of them in a row, and either use six individual of those magnest [way way strong] o ruse like three of them on a flat piece of steel they work great.

u can also use radioshack relays and put one of those magnets on it to make a great sounding hexpickup. or combine six of the relays and a single humbucker [half of the humbucker actually so one coil] and u can lmake a split hum/hex pickup. works killer in hum mode you add in trimers to make it able to balance all the strings.

and in hex mode it lets you trigger hex parts or gives you a great clean tone.

to onvert the relays just put a small nail through them and trim the end of it, theres an article somewhere online here

[psw]

Ansil, Hi

The hex pickup / relay idea is on the pickupmakers forum. I was wondering how they would sound though. Have you actually made this?

Also how effective is the split humbucking Z coil thing? Different polarities for 2 pairs of three strings? I know it's used a bit on basses!

Also. My latest idea for sustainer devices goes along the lines of a piezo element that vibrates these small magnets below the strings causing the magnetic field to fluctuale and sustain the string like the electromagnetic coils currently made. Would this not solve the phase problems, power requirements and reduce the amount of EMI and eliminate RF in the system?

Also, I imagine you could run it backwards so that the magnets, vibrating in sympathy with the strings would cause a piezio signal for an acoustic type of sound! How great would that be!!!!!!

I imagine a set up where the centre pickup in a strat is replaced with this or, made small enough, stuck to the guitar at an optimum location under the srings with no alterations to the guitar at all!

One other thought. Would it not be that bending a peizio element into a concertina shape produce a more dramatic (multiplying) movement of the peizio. A kind of peizio spring.

Anyway, some food for thought! Am still working on these ideas

Any sugeestions anyone?????

[psw]

oh yeah

Here's another idea.

I'm trying to get a hold of the miniture vibration motors used in mobile phones.

These can be as small as 4-5mm, have ammazing speeds ad very low emissions

I thought of drilling into the sustain block or mounting them inside the centre trem spring to cause the bridge to vibrate and drive the strings.

Perhaps 2 to create more complex vibrations.

Any Thoughts guys?

[lovekraft]

I f you want to play with the trem, this may be of some interest to you:

Reverbitar

And before I forget, any two pickups with opposite magnetic phase wired electrically out of phase will be humbucking to some extent - the effect increases as the pickups become more closely matched, and closer in proximity. Even a dummy coil (no magnet) will give you humbucking because it will still cancel the induced noise. HTH

[psw]

Thanks Lovekraft

Looks like the ultimate surf guitar (love that stuff) but I imagine feedback would be a problem and strange squeeks would eminate whenever the trem was used!!!!!!!!!

The trick to making motors sustain strings would be to vary their speed with frequency. I think perhaps that could be impractical but would make an interesting auto subtle but true vibrato similar to a chorus effect. Not actually what I was going for.

Anyone got any good sources for piezo materials other than canabalising buzzers??

I bought out the local of piezo transducers which are great (about 30mm round on thin brass sheet). What I need are thin strips to bend into "spring" like elements to maximize movement of the magnets.

Any ideas?

[lovekraft]

The trick to making motors sustain strings would be to vary their speed with frequency. I think perhaps that could be impractical but would make an interesting auto subtle but true vibrato similar to a chorus effect. Not actually what I was going for.

You'll have to have the vibrator track the fundamental frequency of the note you're playing, the way an EBow does. If you don't, you're going to get intermodulation (sum and difference frequencies) like a ring modulator. If you don't know what I'm referring to, whistle and hum at the same time. It can get quite nasty at close frequencies. So, maybe a hex piezo bridge pickup driving 6 of Ansil's relay coils? Just a thought.

[psw]

Thought that too

Individual coils and piezo drivers with separate driver stages for each string is where I'm heading at the moment.

The motors wouldn't work I fear!

The coil driver across all strings though stimulates them all equally with the same frequency. Separate drivers pickups and amps for each string would appear to be more efficient for the reasons you mentioned, especially if the phase difference created by the inductor of the driving coil (that varies with freq) is overcome.

The result I hope would be more even sustain (notes not winning out within chords) and a more efficient driving system. With use of piezo drivers I hope to get around the complex electronics required to align the phase shifts and some of the EMI from the use of coil drivers.

Perhaps I should start a new thread on sustainer ideas as this is getting away from the posted topic of Rare Earth Magnets.