Demagnetizer to erase tape?

[fred s.]

I've read on this forum you can erase 1/4" with a demag.
I was just wondering what the correct way to do this is.

I'm assuming you just bring the demag up to the reel and then move it away?

[Cosmic]

Fred,

I cannot say I know of using a head demagger for reel erasures. I do own an Ennis Handi-mag, but here is the time-proven way:

Real erasing of a reel comes courtesy of a table-top device which is basically a big magnet with a flat top holding a spindle for the reel to fit on. You plug in, bring the reel on, rotate (depending on model) and remove and you will have wiped that tape as deeply as can be done....and needless to say, you want nothing magnetic nearby that you wish to: save or: operate afterwards.

Go to the Giver of All Things and the Taker of All Money: Ebay, and they are available. I need one too, having recently come to my senses and having re-entered the analog universe again..

Good tools are invaluable. They cost a bit up front, but then you are home, worry-free.

Best,
C.

[N7SC]

FWIW, when I first got my Annis Han-D-Mag, I noticed that the instructions said that you can use it to bulk erase tape. They say that you use the flat end of the Han-D-Mag to do it, not the probe end. So, of course, I had to try it out. After swirling it around all the way around a reel (plastic) of 3M 996 for several seconds, the results were kind of disappointing. It only produced a slight fade in the volume of the material on the tape in places, and none at all in others. Kind of a "wow-WOW-wow-WOW" effect. But, then, it was 996 which has a very high coercivity, and thus is pretty hard to erase. On the other hand, the erase head in my Revox A77 has no problem wiping 996 completly clean though.

I just figured that for bulk erasing, it must be best to buy a bulk eraser. At least for the high-coercivity tapes. The bulk erasers have very much higher field strength than the back end of a Han-D-Mag. Bulk eraser = approx. 2000 or more oersteds, Han-D-Mag back end = approx 800.

[krhall]

On my tape recorder i have a tab that i can press and it covers the playback head on the machine so all i have to to to perform a bulk erase is press this tab load the tape and press play and record and it does the job fine.
As far as demagnetizers are concerned they can be helpful, i read on another forum that you must never plug in a demagnetizer in close proximity to the tape recorder, because it will magnetize metal tape transport parts as opposed to demagnetizing them, it also went on to say that the safe distance to plug in a demagnetizer is 3 feet away from the machine. So what you would do is take the demagnetizer and find an electrical outlet that is as far away from the machine as possible (3 feet minimum) then take the machine to the demagnetizer. as for bulk eraseing, if you are looking for a tool that will prove effective for bulk eraseing then i would strongly suggest a bulk eraser, a demagnetizer may work but it may produce undesirable and maybe even unpredictable results.

Keith

[lukeslim]

Hi all,
i just recieved in the mail today a very old bulk eraser that i brought on ebay Australia have been on the look out for a tape eraser around 12months finally
got one at a fair price cost me $80 AUD including post.
It is a Magnecord reel to reel bulk eraser.Looks like a old 50's/60's unit.
There is no info on how to use it.Can you leave it on for too long?
How long should it take to erase say a 10" tape?Do you turn the Tape over
or spin it as mentioned ?Do you hold down the switch or turn off and on etc?

I have given it a couple of tests seems to work ok,just like to do it the right way.
Cheers Luke.

[krhall]

All you have to do is turn it on and place the tape onto it, then rotate it slowly for about 2 minutes for 10". Also make sure the tape is on a plastic reel "not metal" I wouldn't recomend any longer than about 2 minutes. Also make sure the eraser is not anywhere near your tape recorder. The further away from your tape recorder it is, the safer it is.

Keith

[lukeslim]

Thanks for your input Keith. I feel better now.
Luke.

[krhall]

No problem

Keith

[EDAN]

Originally Posted by lukeslim

Hi all,
i just recieved in the mail today a very old bulk eraser that i brought on ebay Australia have been on the look out for a tape eraser around 12months finally
got one at a fair price cost me $80 AUD including post.
It is a Magnecord reel to reel bulk eraser.Looks like a old 50's/60's unit.
There is no info on how to use it.Can you leave it on for too long?
How long should it take to erase say a 10" tape?Do you turn the Tape over
or spin it as mentioned ?Do you hold down the switch or turn off and on etc?

I have given it a couple of tests seems to work ok,just like to do it the right way.
Cheers Luke.

I read: If bulk erasing tape, don't just set the tape on the bulk eraser and turn it on, erase the tape and turn it off. If you do this, you will leave a pattern on the tape which can be heard if played. As the erase head does not erase all the tape, but leaves a small gap between the tracks, this noise could possibly remain and form an undesired part of the recording. The correct way is to turn on the bulk eraser, bring the tape up to it, erase and slowly move the reel away. If doing tape wider than 1/4", turn the tape over and repeat. Doing both sides gives an even field all across the tape and a more consistent background noise.

[lukeslim]

Hi Edan,
Thanks for that information.

Cheers Luke.