Bulk erasing tape

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ultravioletray
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Bulk erasing tape

Post by ultravioletray » Wed Dec 05, 2007 7:24 am

Greetings,

I realize the first answer some of you may have to this question will be, "buy new tape". I do realize all the benefits from getting good tape. But I'm just getting going here, and trying to keep costs low for the initiation. I'll get new tape soon, within a few pay checks surely.

That being said...

Has anyone bulk erased their own tape before? I've acquired some used tape off ebay - Ampex 456 1/2"x2500'. They seem to be in decent condition, though no telling how old they are, or how they were stored. Some interesting stuff on these tapes (like Church Christmas hymns sung in Polish and two mics on an organ; really spooky...), but I would like to have as clean a tape as possible.

Also acquired from ebay is a Han-D-Mag, which claims one can bulk erase tapes with it. I have tried this twice - both times with the reel on it's side, starting from far away, slowly moving closer, and the other end of the Han-D-Mag (the flat end of the "handle", not the "probe", as shown in the accompanying manual) along the edge; then backing off, turning off the Han-D-Mag, flipping the reel, and proceeding as described. The difference in the second time was I removed the outer parts of the reel, to get at the tape easier, the theory being the metal was "blocking" the erase process. I also did it a bit longer, like three minutes on each side. Patience is a virtue, right?

The results are less than spectacular. Though it erased some, what remains of the sound is "throbbing", though the signal noticeably less in dB's. Aside from erasing the tape off the machine, are there any other suggestions? And/or, would bulk erasing do a better job than erasing off the machine?

Thanks,

dAve
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inverseroom
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Post by inverseroom » Wed Dec 05, 2007 7:27 am

I don't think you're supposed to turn the Han-D-Mag on while using it to erase tapes.

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A-Barr
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Post by A-Barr » Wed Dec 05, 2007 7:37 am

Here are some tape erasers, man, are they expensive!

I wonder if you could DIY one by just building a huge electromagnet.

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ultravioletray
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Post by ultravioletray » Wed Dec 05, 2007 7:47 am

inverseroom wrote:I don't think you're supposed to turn the Han-D-Mag on while using it to erase tapes.
Hmmmm. Possibly. I figured it is an electromagnet (wrong?) which needs to be plugged in, so....

The accompanying literature only said it could be done, followed by a picture (if I had a scanner, I'd post it). No actual instruction on how to do it. Theory is all I have, at the moment. I'll try yr suggestion.

Thanks,

dAve
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ultravioletray
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Post by ultravioletray » Wed Dec 05, 2007 7:52 am

A-Barr wrote:Here are some tape erasers, man, are they expensive!

I wonder if you could DIY one by just building a huge electromagnet.
Ouch! They are. Even the hand held is $150. It does say it works for 1/2" tape. And if the cops use it, well, it must be good:

"Very popular with police departments for bulk erasing in car video tapes for re-use."

Multi-purpose. Nice.

I'd be interested in building one. Not sure how one would do so. Anyone?

Thanks,

dAve
"Forever Alive; Forever Forward."
Walt Whitman

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Judas Jetski
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Post by Judas Jetski » Wed Dec 05, 2007 5:05 pm

A-Barr wrote:Here are some tape erasers, man, are they expensive!
:shock: OK, looks like I have to find a new place to keep my bulk eraser... :shock:
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brianroth
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Post by brianroth » Thu Dec 06, 2007 1:08 am

Back "In Ye Olde Daze" <g>, the Taber desktop units were what I saw everywhere.

Indeed, they housed a huge electro magnet that had a "power ramp-down" after a preset time. You manually rotated the reel on the spindle while the timer ran out. With 2" tape, I found you had to flip the reel over and do the process again.

The electromagnet in the Taber pulled maybe 10 or 15 Amps while it was working.

Just random info on the topic...

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paully
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Post by paully » Thu Dec 06, 2007 12:02 pm

If that Ampex 1/2" tape came on metal reels, you probably should transfer to a plastic reel in order to do a good job with a hand-held unit.

BTW, turning them on/off near the tape shouldn't hurt anything. It's the head degaussers that should be turned 'on' at a distance, moved close slowly, then reversing the proceedure for turning 'off'. I actually use this procedure when erasing tape by hand, probably out of habit. This old thing was inexpensive, and still works for all types of tape:

Image


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Post by bluesman » Thu Dec 06, 2007 12:56 pm

spiral in, spiral out, flip tape over & do both sides, never turn off demagnatizer until after spiral out, otherwise you will create a huge WHOOMP! I have used large ceramic speaker magnets with good results. It has more to do with technique.....any strong magnet can & will work with proper technique. Take your time, turn the tape on all sides, keep the magnet in motion & like I said, spiral in, spiral out.
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A-Barr
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Post by A-Barr » Thu Dec 06, 2007 1:05 pm

This may be totally, or at least moderately off topic but....

Is it crazy for me to try to de-magnetize a speaker in order to make it less efficient? (the whole cranked amp, low volume thing...)

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Post by Judas Jetski » Thu Dec 06, 2007 2:16 pm

bluesman wrote:spiral in, spiral out, flip tape over & do both sides, never turn off demagnatizer until after spiral out, otherwise you will create a huge WHOOMP! I have used large ceramic speaker magnets with good results. It has more to do with technique.....any strong magnet can & will work with proper technique. Take your time, turn the tape on all sides, keep the magnet in motion & like I said, spiral in, spiral out.
Ooh, spiral in and out. Good tip. 8)

I tend to just go in slow, with some good result. But that takes a long time and may exceed the duty cycle of my bulk eraser. Which I have to take good care of now that I know I probably can't afford to replace it.

I've never had a problem with using a metal reel, but then I've never used a metal reel that isn't aluminum and therefore not susceptible to magnetism. Should I be thinking about the screws holding the flanges on?
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Post by ??????? » Thu Dec 06, 2007 3:03 pm

A-Barr wrote:This may be totally, or at least moderately off topic but....

Is it crazy for me to try to de-magnetize a speaker in order to make it less efficient? (the whole cranked amp, low volume thing...)
I would bet that if you e-mailed a certain speaker-making dude whose initials are T.W., he might take the time to respond to you thoughtfully. He's pretty cool like that espesh if you've bought shit from him before. I refer to him by his initials because I don't want to volunteer a stranger's services over the internet. :D

My hunch would be that it would be risky and hard to do incrementally and with any predictability.

The best way to slightly demagnetize the magnet, if you wanted to, would probably be to drop it on the ground over and over, or hit it with a hammer a bunch of times. Like for real.

But I do NOT recommend any of the above. :D

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