Demagnetizing: A few questions

[moogplayer]

I clean my tape heads regularly, but have heard conflicting advice on if/when to demagnetize. Would love to hear what y'all think of this.

A few questions:

1. What is the correct way to demagnetize the heads?

2. How often do you demagnetize?

3. Does demagnetizing really help? Is there an audible difference?

[guitar4lyfe]

well u can get a demagnetizing cassette from radioshack for cassette players or u can get a de-gausser which is like a lil rod that u touch to demagnetize things. If you use any cassette or tape players regulary it should be good to de-gause(demagnetize) once every 2 weeks-1 month. Demagnetizing does help, it doesnt help sound quality already on the tape but what happens is when excess magnetism builds up on the play head (Record heads demagnetize themselves when they are turned on) the excess magnetism will end up erasing over time the higher frequencies that are recorded on the tape, so its a good idea to demagnetize.

[xonlocust]

your tape machine should have directions - but the basic principle is...

1. remove ANY tapes/magnetic material away from the area (like 10 ft or so)
2. stand about arms lenght from the machine
3. hold the demagnetizer arms lenght away from the machine and plug it in
4. slowly move it in towards the heads and tension arms, etc. start with one, say the left tension arm, approach slowly - move around the part - then pull away slowly. repeat for remaining "magnetizable" pieces in tape path

you dont want to actually touch the demagnatizer to the components. fortunately - the most common "pro" demagnetizers have little boots on them to keep them apart. they're called han-d-mag's - you can find them on ebay, or i think blevins has them as well.

http://www.blevinsaudioexchange.com/handmag.html

you can also get cheaper radio shack ones, but i dont trust them. the just dont seem robust enough to me. i got mine for like 30 bucks at music-go-round.

i demagnetize before a new session when i calibrate the machine - so like i'd do it before tracking the project, and then probably right before mixing as well. once you have the thing, you may as well use it right?

so that covers 1 & 2, from my point of view at least, for what it's worth. others may have differing opinions.

[Al]

If your using the machine on a regular basis,i would demag at least once or twice a week.
Or before a major recording session,or before a mix.

Like Xonlocust said,if you have one use it regular,that's what it's there for.

And also his instructions for the use of the demagnetizer have just saved me the bother..cheers

AL

[SpaceCad]

I have a sub question: What is a good demagnetizer for a 4 track RtoR? From what I've read, most recommend the Han-D-Mag which is like $50 and from what I understand, geared toward 24-track heads.

Is there a cheaper alternative?

[Al]

Any cheap end demagger will do you just fine,better than none at all.

[percussion boy]

Don't forget to keep your credit & ATM cards away from the demagnetizer when it's on . . .

[xonlocust]

if you're going on the cheap

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... egory=1602

or

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... egory=3278

personally i'd get the han-d-mag - but the small one may be just fine for 1/4" or 1/2".

[SONICLAB]

Make sure the tape machine is off before demagnetizing!!!

[percussion boy]

you dont want to actually touch the demagnatizer to the components. fortunately - the most common "pro" demagnetizers have little boots on them to keep them apart.

When the demagnetizer has a *rubber sleeve* over the metal tip that comes closest to the heads, is it still important not to actually touch the heads? (Or is "sleeve" another way of saying, "little boot"?)

I've heard conflicting advice on this and have always wondered. I don't want to scratch the heads, but my guess is that the sleeve protects against scratching if I touch the sleeved part of the HanD-Mag to the head surface.


[edited to add quote]

[Electricide]

don't turn your de-magger on or off anywhere near the machine. Approach and retreat from the machine with the demag on.

That's all I know

[Al]

Absolutley cman548!!,this can of course lead to disasterous consequences.

The heads can become permanantly magnetized,in which case you would need a stronger demagger to undo what you did,and this is not always possible to do,it's a last ditch thing!

That's why they recommend you dont use one with a switch,i do,but be very carefull...if in doubt get a tech to show you the procedure,it's a very weird one which i normally do when no one is around,i had a musician in once while i was demaggin',he thought i was mad!!,he had never heard of this before,and he honestly thought i was winding him up!!

[xonlocust]

When the demagnetizer has a *rubber sleeve* over the metal tip that comes closest to the heads, is it still important not to actually touch the heads? (Or is "sleeve" another way of saying, "little boot"?)

excellent question - i asked that very question at the tapeopcon at the anaolg machine maintenance panel. the answer given to me was that the rubber sleeve/boot thing is what physically separates the demagger from the heads, and that it is OK to touch the heads (with the boot on, since you're not ACTUALLY touching the heads with the metal piece doing the demagging - the boot is providing a small buffer) - so, it's ok to touch the heads, only insofar as you aren't *actually* touching the heads - get it? it's like make sure your demagger had a condom on if you're gonna bump uglies - otherwise don't go in there all the way.

i hope i'm not belaboring the point, but everyone realizes it's the metal piece emitting the charge, and not the plastic boot on the end right? so if you've got a cheap one off ebay or something (not han-d-mag) that doesn't have a boot, don't actually touch the heads.

[The Scum]

2. How often do you demagnetize?

3. Does demagnetizing really help? Is there an audible difference?

A couple of points that have been hinted at above:

Demagging is a little risky. If you kill the demagger while it's near ferrous parts, you will magnetize them. That's why we do the funny dance, plugging it in far from the machine, and unplugging it far from the machine. That's also why a demagnetizer shouldn't have a power switch...one less thing to goof up.

Try plugging & unplugging with it near a screwdriver, to see what it can do. Then do the powerup-sweepin-sweepout-poweroff to cure it.

There's some good wisdom about demagging to be found on the web and usenet:

MRL Demagging paper.

Enlightening R.A.P. discussion of demagging. Click on the links you'll get for the longer posts.

I've also known "old-timers" who tap their razorblades on something solid before doing any tape edits, to try to disturb any residual magnetization they may have picked up in storage...they say it helps avoid pops on the edit.

Byron Jacquot

[cyrusjulian]

Just wanted to add that you might want to look into purchasing a Magnometer. ( I think that's how you spell it. ) They're made by R.B. Annis in Indianapolis, IN. They're the same company that makes those Han-D-Mags. It basically measures any level of magnetism that may be present in your heads or other parts of the machine. I like it since it saves me time by not having to demagnetize my machine when it doesn't show any levels of magnetism. Lastly, I recently spoke to a tech from R. B. Annis and he said that the "butt" end of the Han-D-Mag actually has a higher concentration of demagnetization so if you have any problem areas, you might want to try and demag using that end instead of the end with the plastic tip.

Just wanted to add my opinion...