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How does a horseshoe actually work?

Posted: Wed Sep 27, 2006 5:44 am
by philipharris
I'm no tech-head - I just play them, and I never really think about what's going on under the bonnet. But I got to wondering, as the original h/s is so idiosyncratic compared to other contemporary pups, how does it actually work? Are the poles magnetised as well the shoes? What role do the shoes play? Sorry to profess ignorance. I'm no good with cars or barbeques either, which is why I'm a trade mark lawyer, not a patent attorney I guess.

Posted: Wed Sep 27, 2006 6:01 am
by jnbass
calling Mr Pick-up,

Sergio!

Posted: Wed Sep 27, 2006 6:17 am
by jwr2
I believe the horseshoe pickup was the first pickup for the electric guitar ...

The shoes on the horseshoe pickup was magnetized steel ... this surrounded the strings with a magnetic field ... the problem is that steel is prone to degaussing ... modern pickups have alnico (aluminum, nickel, cobalt and iron) magnets in them or they have a base magnet with steel or iron pole pieces ...

Image

as per trademarks I believe the shape of the horseshoe is a registered trademark that belongs to Rickenbacker ...

Posted: Wed Sep 27, 2006 7:40 am
by rickfan60
Magnetic pickups work by setting up a magnet field around a coil of wire. As the strings vibrate in the field they disturb the field slightly and induce a small current in the coil. The strength and shape of the field determines the strength of the resulting current. Horseshoe magnets setup a different field shape from that of a bar magnet. No, the poles on an old HS pickup are not magnetic. Only the shoes are.

Posted: Wed Sep 27, 2006 7:57 am
by soundmasterg
There are restrictions with trademarks as far as the function is concerned. I'm not a legal expert or anything, but if a trademark has been issued for something that is based on a functional aspect of a design, then it is possibly reversible.

Posted: Wed Sep 27, 2006 10:06 am
by johnallg
To add to Ted's excellent post the horseshoes sense string movement is all directions of vibration (up/down, side to side, etc.), whereas the magnetic pole type pickup is mainly in the horizontal (back and forth) direction. That is why the horseshoe pups are very good at reproducing the dynamics of playing also.

Posted: Wed Sep 27, 2006 10:35 am
by rickfan60
Yeah, different magnets in different orientations can produce different tone colors and dynamics. Permanent magnet technology was not very good in George Beachamps day. Pre-war magnets tend to be pretty weak. Not so much because they have degaussed but because they where not heavily gaussed to begin with. Compared with the industry today, he had a very limited field of choices. I don't know if George was able to use bar magnets or even if he had access to cylinder magnets. My guess is that fairly weak horseshoes made of tungsten alloy were his only real options.

Posted: Wed Sep 27, 2006 2:56 pm
by rickcrazy
"Mr. Pickup" got in a bit late today. Sorry. But I don't think I would have been able to elaborate on the subject matter any further than Ted has.

Posted: Wed Sep 27, 2006 4:32 pm
by rickfan60
Thanks Sergio. Those are just the broad strokes. I am not clear on how the field and phasing work or the dynamics of the coil windings - symmetric versus scatter winding.

Posted: Wed Sep 27, 2006 4:45 pm
by wayang
A horseshoe works just like a hand grenade...

Posted: Wed Sep 27, 2006 4:50 pm
by johnallg
Ok, I'll bite......

Posted: Wed Sep 27, 2006 4:59 pm
by wayang
John...you've never heard the phrase "Close enough for horseshoes or hand grenades"?

Of course, there are differences...no one's ever stuck around to report on the difference between a 'leaner' and a 'ringer' when playing 'hand grenades'...

Posted: Wed Sep 27, 2006 5:41 pm
by johnallg
Ok, Dane, now it makes sense for me! As for the difference, probably the difference between a stretcher and a pine box.

Posted: Wed Sep 27, 2006 11:05 pm
by philipharris
Thanks everyone- this place is brilliant....

Posted: Thu Sep 28, 2006 9:49 am
by johnallg
At times, Phil! :D Sometimes it wanders far afield! But then that makes things interesting too, and I even learn new "old saws".