Hand-wound Coils

[biasply]

Hello Trolls!
I've only recently discovered diy record cutting/found this site .... can't believe it's possible - I've always been a diy/hand packaged music type - but this is awesome....

Anyway, I was lurking for a week and now I'm in, gonna build something, and here's my first question:

With the objective of small and light for the cutter head, what about getting 1/4"d. (or 1/2") Neodynium magnets and hand winding coils? (Aside from being tedious that is.)
Unless I have my numbers wrong, 50-60 turns for 8 ohm resistance, and would (guessing?) require less amp power. True, it would result in less force, but if the stylus support/composition was also modified to reduce weight, could this all work together?
Would there be enough excursion?

I'm going to try it anyway, but I wanted to ask for second opinions....

Also having trouble locating small spools of magnet wire in anything other than copper, anyone have leads?
Aluminum and silver it seems produce more SPL (which I take to mean more excursion/movement for the stylus).

The reason I'm trying to get so very small, is that I want to design a (usable) system that will fit onto my regular home deck. And by this I mean the cutter being built into a stripped cartridge to interchange with my regular one, and a motor system that slides onto the back of the tone arm, replacing the counter weight. A better description of my motor idea will come later, it really does make sense...
I'm not looking to rival a $10,000 cutting system, but I would like to come close to some of the essence of 1970s Jamaican vinyl - Lee Perry etc.

Cheers
Steve

[EmAtChapterV]

The resistance of a wire depends not only on its length, but also on its gauge - http://en.wikipedia.org/wiki/American_wire_gauge . There will be a trade-off between how much wire will physically fit into a given space, how much resistance it will have given a certain gauge (not enough resistance means too much current and the amplifier becomes very unhappy and unstable), and a coarse enough gauge that the wire will be able to handle enough current without burning up.

The advantage of silver or aluminum wire, as I understand it, is less heat buildup, and less weight.

Professional cutterheads also have feedback coils, meaning the movements the stylus is actually making (versus the movements it ought to be making) are fed back into the recording chain, and motion that's not meant to be happening is cancelled out. This makes the system as power-efficient as possible.

[biasply]

Thanks, and I guess at the very least, all I need to do is meter the resistance to see if I got it right.
Any comment on the actual size being so small? Is there too small with kind of thing?

This is a gross oversimplification, but it's what gave me the idea
http://www.instructables.com/id/Styrofoam-Plate-Speaker/step3/Finish-the-Voice-Coil/


Feedback signal, I agree it'll increase my fidelity, but that's down the road for me I think.

S.

[markrob]

Hi Steve,

There is quite a bit to the physics of head design. There are a number of related parameters. First design choice you need to make is the type of head you wish to build. The two main types in use today are moving iron (e.g. Presto 1D) and moving coil (e.g. Nuemann SX74). If you are interested in the technical details and pm me with you email, I can send you a scan of some textbook material that has a nice expalnation of the moving iron style head design. Most of the principles can also be applied to moving coil designs. Its not overly math heavy, but it does require some math/physics background.

Mark