re-magnetizing horsehoes...

[brycycle]

i can get my hands on some RE magnets easily - can some-one give me a step-by-step on how exactly i would use them to re-gauss the shoes?

much appreciated.

[rickfan60]

That is a good question. I suppose long, flat RE magnets laid along (not across) the top and bottom legs of the HS would work. If you are using NIB magnets you should notice a change in gauss overnight.

You probably already know this but please be careful when handling strong permanent magnets. They can accelerate toward iron or another RE magnet at amazing speed. If your hand or anything else is in the way it could hurt a lot. One manufacturer's website says that NIB magnet fragments can actually ignite if the force of impact is great enough.

[johnallg]

Good advice about strong magnets Ted. Blood blisters hurt!

Bryce PM'd me and this is what I wrote him. If anyone has more to add or corrections, hop right in, please.

"Yes the shoes have to be off the pickup, loose. John Hall has said that when the shoes are oriented like when they are mounted on the pickup, they have to oppose. If you remember how the shoes were sitting on that woofer magnet in the picture that was posted on the forum, that makes the top of each shoe touching the "top" of the woofer donut magnet, and the bottom (side with screw holes) of each shoe touching the "bottom" of the woofer donut magnet. This both puts the lines of flux of the woofer magnet through the horseshoes and makes them the same polarity. It really doesn't matter if it is N or S, just so they are the same, at least in my opinion. Phasing of the pickup really comes from direction of the windings of the wire on the coil as I understand it.

So, I have these about 1" square magnets and I stack two as that makes the right height to just fit into the gap of the horseshoe. I put about 1/4" into that gap, then put the other shoe with the same orientation (screws of both shoes to the same side of the magnets) and make the shoes face each other like when mounted to the pickup assembly.

Hope this is clear. Oh, as to originally orientating the magnet(s) to your shoe, slowly and gingerly let it approach the shoe and you should be able to "feel" if it is oriented correctly. It should want to pull itself into the gap and not have the top of the magnet trying to pull to the bottom of the shoe arm, if you get what I mean. If that happens, just turn the magnet over. If there is no difference, then the shoe is really weak and it shouldn't matter one way or the other, but my guess is you will feel even a slight tug to be able to tell the optimum way to put the magnet into the gap."

[Lost Coyotes]

Great post, John.
Gonna copy/paste that to file in case it's needed here...
THANKS!

[johnallg]

My most reassuring statement about my post is it worked for me. Thanks Mike.

[rickfan60]

Great info John! Thanks for posting that. I would also add that the shoes are not identical the EA shoe has a slightly wider opening that does the GD shoe. Be sure to orient them properly when reassembling the pickup.

[johnallg]

Great info John! Thanks for posting that. I would also add that the shoes are not identical the EA shoe has a slightly wider opening that does the GD shoe. Be sure to orient them properly when reassembling the pickup.

Huh, you know I'd noticed that but never made that connection. Thanks!

[wints]

Thanks for that informative post John.

[johnallg]

Thanks, Andy. Bryce needed clarification, so I drew this. Lousy, but it shows what I mean.

[rickfan60]

Thanks, Andy. Bryce needed clarification, so I drew this. Lousy, but it shows what I mean.

That is pretty much how I pictured it. Thanks for the clarification John.

[wints]

That could almost be my smile when I get finished and have new gauss....

[johnallg]

I actually have one more magnet shoe pickup waiting for a chance. I checked it today for magnetization and it grabs an allen key really strong still, so the magnetism is lasting. I need a chance to swap it into my '04 replacing the RIHS to see if I like it better - less windings on the coil.

[johnallg]

Lastly Bryce asked, "the gap between the shoes would equal approx 1/4"?" To which I replied:

"The gap is whatever width the magnets are and is really unimportant unless it is less than the gap when the shoes are mounted for use - you don't want them touching. I believe mine is 1/2" to 3/4" but like I said, not important as you are only charging the shoes and will remove the magnets after 24 hours or less. Because of the polarity when charged, the shoes will repel each other when facing like when mounted for use.

Remember the shoes on the woofer? They didn't even face each other and were not in close proximity. While charging, the important thing is a strong enough magnet(s) and polarity. I charge mine facing like in the drawing to insure polarity.

[pacealot]

After scrabbling around inside my old CPU in vain to try to find some RE magnets, I finally had a moment alone with my horseshoe and my gigging speaker cabinet, and so I was able to try Steve's speaker magnet technique, and I must say it really did make a difference. As it had been, the 'shoe was working just fine, but it had always been noticeably lower output than the toaster even factoring in the .0047uF cap, and I'd additionally been starting to wonder if it was fading, or if I was just imagining it (since I nearly always run it in stereo, it's hard to be sure). I have an Eminence Kappa series 15" with a ceramic magnet in my cab, so I stuck the shoes on just like Steve did and left them on overnight (maybe on for 9 hrs. altogether), and, after reassembly, the output of the horsie is a lot closer to that of the toaster, even with the cap in (I summed the bass back into mono even to check it out). It may have been a small difference in magnetism, but it is audible and certainly seems like an improvement overall!

It'll be interesting to see how long it stays....

[johnallg]

I always like to do a before and after strength test using the shoe to pick up a bigger screw, small screwdriver, or last time I just stuck the shoe to the vertical surface of a metal desk (easily available). Before it would not stay stuck (support its own weight) but after it hung on nicely.