Fun with magnets

[wankdeplank]

Not your garden variety ceramic. I've never heard anything like it, not ceramic like at all in the tonez dept. - sounds like a tenor sax. High-end boutique; something the original owner put in and he's one of the busiest gigging musicians in town. Nothing wrong with a good ceramic.

[wankdeplank]

Wonder if he filed a big lawsuit like Hulk Hogan when his sex tape went viral.LOL But yeah it's definitely something that we as electric guitar players have to pay attention to.

[Ratae Corieltauvorum]

I read once that Andy Summers of the Police was riding on the NYC subway with his guitar and apparently he was sitting really close to a transformer or train motor or somesuch electronics and it totally demagnatized the pickups in his favorite guitar. He had to have the pickups recharged by Seymour Duncan. I read the story on Seymour Duncan's web site but it's not there anymore. Just third-hand accounts from other sources via google search.

 

 

Funnily enough, I learnt all my magnet {censored} when I sold a set of Seymour Duncan Custom DShop Dynasonics to a guy who lived nearby. He wanted them for his Gretsch Duo Jet. When he bought them, he asked me if I'd install them too, so I did, handed back the guitar and got a call later on that the guitar was dead.

 

Got him to bring the guitar back, a tad sceptical that I could have {censored}e up that badly as I'd done a quick test to see if the switching was all ok.

 

Anyroad, after a lot of head and chin scratching I noticed that the pickups couldn't even support the weight of a paper clip, and aftre some enquiries at the Physics department here at the Uni, got them measured, and they had residual magnetism in them.

 

Seemed they left the Custom Shop uncharged, and returning them to the SD CS, was gonna cost too much in postage and take too much time, so one of the Profs there told me how I could charge them myself.

[Ratae Corieltauvorum]

I've heard that somewhere

[Phil O'Keefe]

I read once that Andy Summers of the Police was riding on the NYC subway with his guitar and apparently he was sitting really close to a transformer or train motor or somesuch electronics and it totally demagnatized the pickups in his favorite guitar. He had to have the pickups recharged by Seymour Duncan. I read the story on Seymour Duncan's web site but it's not there anymore. Just third-hand accounts from other sources via google search.

 

 

I think I've read or heard that somewhere too. A buddy of mine did the Andy Summers Fender Custom Shop Custom Telecaster recreations and has been all over the original; I'll ask him if he's heard anything about that.

[WRGKMC]

We have a charger here in the shop. Its mainly used for magnetizing screw drivers so the techs can hold onto screws repairing equipment.

 

Its a simple device. You could even make one from an old power transformer if you have the patience. You'd remove the iron plates in the transformer and make it into an air core. Then use a switch to activate it.

 

Since there's AC passing through it, it works both as a magnetizer or demagnetizer depending on the position of the metal you're magnetizing.

If you put the metal evenly inside the transformer core it will demagnetize. If you hold the tip partially in so the field is pulling the strongest on the metal it will magnetize.

 

You wouldn't think and AC field could both magnetize as well as demagnetize. You'd think it would need to be a DC voltage to get a steady polarity to magnetize metal, but it in fact does work.

 

This is a primitive way of charging a magnet however. You have no means of knowing exactly how strong you've magnetized it, and the position within the field will impact its strength too.

 

If you had a magnetometer (cost between $64 and $145) you could measure its strength, then use a Variac on the coil to vary its strength.

http://www.lessemf.com/dcgauss.html

 

 

 

 

 

 

 

 

 

 

 

 

If you were into winding your own, you could use the gauss meter in this winder.

 

 

[Zoobiedood]

I have done a lot of magnet swapping in pickups, from A2 to A8, and Ceramic (roughcast and unoriented too), but never altered the magnetism. It would be fun to play around with though!

[*BLEEP*]

...I've done a ton of degaussing of tape heads. It has always been one of the maintenance procedures I am as cautious as possible about performing' date=' since doing it wrong can permanently magnetize the tape heads and other parts of the tape path... [/quote']

 

 

 

Degaussing the heads -- as well as the capstan(s) or tensioner/guide -- in this case, is done with an auto-magnet. I'm sure you recall when you were doing this operation that the degausser was buzzing away at 60 Hz (or 50 Hz) and there was an insulated tip on the end of the degausser.

 

Since this particular degausser for this sort of work is an auto-magnet (an AC magnet), the magnetic field is basically rotating like a globe when it is powered. Turn the power off and there is no magnetic field. However, if you were to abruptly turn this degausser off during a deguassing operation with permeable objects -- such as tape heads or a capstan -- they would become magnetised in whatever magnetic field orientation the degausser was at during the moment that power ceased.

 

The procedure is to touch the insulated soft tip of the degausser to the heads, capstan(s), and/or tensioner and s-l-o-w-l-y pull away from the area before tuning off the degausser. What happened was that the magnetic field saturated the parts, with polarity rotating north-to-south at 60 Hz. After a second or so of magnetically saturating the heads, you slowly began pulling that rotating magnetic field away from the head as you backed away from the parts. The diminishing rotating magnetic field would leave behind no latent magnetic flux.

 

Some are possibly wondering how the did these parts get magnetised in the first place? The answer is mainly due to contacting magnetic recording tape over a long period of time. But, they could have been magnetised by being near some other magnetic source or even from the Earth's magnetic field -- which would be even more the case if you had a recording studio near the North Pole or South Pole in Antarctica. As faint as it is, the Earth's magnetic field can degrade magnetic recording media if that media is not "rotated" once every few years.

 

 

 

[*BLEEP*]

I read once that Andy Summers of the Police was riding on the NYC subway with his guitar and apparently he was sitting really close to a transformer or train motor or somesuch electronics and it totally demagnatized the pickups in his favorite guitar.

 

 

 

I believe the story was that Summers' Telecaster bridge pickup seemed as if it had become weak, so Andy Summers had Seymour Duncan to look over the pickup and tone circuit, when he was in the States on a tour. It was discovered that the magnets in the bridge pickup were weaker than normal (guessing A5 magnets with A2 strength).

 

Seymour Duncan recharged the barrel magnets to full strength. But, Andy Summers didn't like the result so much (ice-pickey?). So Seymour Duncan went and degaussed them a just a bit and Andy liked the results. I believe that this incident lead to the much-ballyhooed term "aged magnets."

 

Also, the theory behind how the pickup became demagnetised was that it was from repeated near-daily rides on the London Underground (the tubes / subway system in London UK), where Andy Summers would *always* sit in the back of the train, where others wouldn't, near the warm purring electric motor with the geetar up against the motor.

 

 

[Phil O'Keefe]

 

Degaussing the heads -- as well as the capstan(s) or tensioner/guide -- in this case, is done with an auto-magnet. I'm sure you recall when you were doing this operation that the degausser was buzzing away at 60 Hz (or 50 Hz) and there was an insulated tip on the end of the degausser.

 

Since this particular degausser for this sort of work is an auto-magnet (an AC magnet), the magnetic field is basically rotating like a globe when it is powered. Turn the power off and there is no magnetic field. However, if you were to abruptly turn this degausser off during a deguassing operation with permeable objects -- such as tape heads or a capstan -- they would become magnetised in whatever magnetic field orientation the degausser was at during the moment that power ceased.

 

The procedure is to touch the insulated soft tip of the degausser to the heads, capstan(s), and/or tensioner and s-l-o-w-l-y pull away from the area before tuning off the degausser. What happened was that the magnetic field saturated the parts, with polarity rotating north-to-south at 60 Hz. After a second or so of magnetically saturating the heads, you slowly began pulling that rotating magnetic field away from the head as you backed away from the parts. The diminishing rotating magnetic field would leave behind no latent magnetic flux.

 

Some are possibly wondering how the did these parts get magnetised in the first place? The answer is mainly due to contacting magnetic recording tape over a long period of time. But, they could have been magnetised by being near some other magnetic source or even from the Earth's magnetic field -- which would be even more the case if you had a recording studio near the North Pole or South Pole in Antarctica. As faint as it is, the Earth's magnetic field can degrade magnetic recording media if that media is not "rotated" once every few years.

 

 

 

Great post and 100% on the mark.

 

What I was always afraid of was tripping over something while slowly bringing the wand either towards or away from the tape deck and losing my grip on that "on" button and ruining a set of heads... or slipping or getting distracted and having the un-insulated side of the tip come in contact with a tape guide or something... so I always approached the procedure very cautiously and tried to focus on it very carefully. I still do it the same way to this day whenever I degauss one of my analog decks.

[Grant Harding]

This is all new to me! Thanks!

[wankdeplank]

Cool, I'm learning a lot as well.

[Phil O'Keefe]

This is all new to me! Thanks!

 

[guitarcapo]

I've even heard people talking about how they STORE their pickups (and how they should be stored in retail settings)

 

The idea is that the magnets from two pickups, if set too closely to each other, could demagnetize each other if oriented in a direction where the two repel each other. Of course the opposite idea....that two magnets oriented so they attract each other could help preserve magnetic strength might also hold true.

[wankdeplank]

I've got my old displaced pickups scattered in various locations for that very reason. Save for the ceramics which are basically indestructible. No real organization to it though and it's going to be an easter egg hunt tracking some down if I ever get another project guitar to put some in.