demagh question

[morte sicura]

Hello! I bought a Nortronics demag tool on eBay. How do I test it to make sure it is functioning properly before I use it on my deck?


Thanks,
Andrew

 

[RICK FITZPATRICK]

Thats a good question, and I asked it on the tascam forum too. The answer got pretty deep and wasn't worth doing for what your doing. Ha, I think it envolves a measurement tool for magnetic fields. Too deep for me. But the bottom line was, if it was vibrating, it is working as the part that is vibrating is inherently in the circuit, and that IS what tells you its working Proof though, is not worth the hassle, unless your that kind of guy!!
Two main things, UNPLUG your deck. If you start to demag with the deck power on, you can permenently damage audio circuits. Start the demag tool at least 18" away from the deck and move in SLOWLY! WATCH WHAT YOUR DOING. As the tip approaches the parts in the TAPE PATH, you can feel the vibration get stronger. From what I understand, that has nothing to do with demagnetizing taking place. Only metal in the field. Move it in and around the guides at one end of the path, capstan, heads and on to the other end of the path. Then move the demagnetizer out away at least 36" and ONLY THEN TURN IT OFF. If you turn it off close to the heads you can PERMENENTLY MAGNETIZE them. THAT WILL BE THE END OF THEM. You will not be able to demag them anymore. Does it have a plastic cover on the tip? IF so, get the tip as close to the head as possible WITHOUT TOUCHING ANYTHING, especially the HEADS. A good cleaning BEFORE demaging and AFTER is also a good habit to get into. I forget the reason for the second cleaning, but it made sense to me when I read it.
You may already know this stuff. In that case, ignor me.
Good luck.
fitz

 

[regebro]

As the tip approaches the parts in the TAPE PATH, you can feel the vibration get stronger. From what I understand, that has nothing to do with demagnetizing taking place.

Well, yes, and no. What you feel is the demagger MAGNETIZING of all metallic stuff, including the head. What you want to happen is actually to magnetize everything so much that its saturated with magnetism, which is what happens when you are close. It happens 100 or 120 times a second, to be specific.

When you then move the demagger away from the r2r, the magnetism of the metallic parts will continue to oscillate with themagnetic field emitted from the demagger, but since the field gets weaker and weaker, the oscillations will be weaker and weaker, until they finally are so small as to be insignificant, and the r2r will then be demagnetiwed.

If you turn it off close to the heads you can PERMENENTLY MAGNETIZE them. THAT WILL BE THE END OF THEM.

Not at all. Worst case scenario is that you turn it off just as the field is at it's strongest. Then the heads will be saturated with magnetism. This however, can be removed by further demagnetization. Several rounds of it may be needed, I don't know, I haven't done any practical tests of this.

I will someday when I'm bored. Get a bunch of nails and needles, and try to magnetize several nails by turning the demagger off wile holding a nail close to the tip. (Do it nail by nail).

The nail that lifts the most needles are the most magnetized one. Take that and do a demag-procedure on it. See if it still can move a needle (or better yet, see if it can move the needle of a compass). If it can't, you successfully demagnetized it.

Does it have a plastic cover on the tip? IF so, get the tip as close to the head as possible WITHOUT TOUCHING ANYTHING, especially the HEADS.

This is even more important if it does NOT have a plastic cover.

 

[Track Rat]

I have no emperical evidence of this but have always heard that you can indeed permanently magnatise the heads/tape guides which ruins them. I could be wrong but this is what I've heard.

 

[regebro]

Well, from my understading of physics and the expermients on magetism I did inb school, there is no difference between "magnetic" and "permnantly magnetic". What you will do is that instead of demagnetizing the head, you will radically *increase* the magnetism in the head. But as far as I understand it, there is nothing irreversible about this. I suspect it's a myth, but I can't prove it.

Still, turning the demagger off close to the r2r is a very bad idea.

 

[RICK FITZPATRICK]

I certainly wouldn't argue with a genius. I should have disputed the Tascam manual first, from which my statement was taken. They said "irreversably magnetized". I guess they don't know shit Thanks regebro. I guess it takes a false statement to bring about clarification.
fitz


PS Hey regebro, what is dub?

 

[Track Rat]

PS Hey regebro, what is dub?

It's Reggae ain't it?

 

[regebro]

Well, no, but almost.

Think of dub as a slow, electronic reggae with loads of delays. I'm sure you can find loads of dub on Kazaa or something.

 

[RICK FITZPATRICK]

Thanks trackrat and regebro,.......oh, your screen name reflects that also, is that correct?
Where are you guys? I'm in the middle of California, USA. And it sucks. Tooooooo many people, too many cars, too much dust and tooooooo much government!

Ha! I was guessing dub was beer or some drink. What a moron.
fitz

 

[regebro]

Thanks trackrat and regebro,.......oh, your screen name reflects that also, is that correct?

No, it's not, actually. It has absolutely nothing to do with any kinds of music.