Demagnetizing considerations

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Victory Pete

Victory Pete

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I am currently demagging my Tascam fleet. I have always demagged anything in the tape path including aluminum tension arm rollers and rubber rollers. I like to make sure I get any residual magnetism that may be present. Also my power goes out frequently here for some reason and I am constantly aware of the danger of losing power while demagging, apparently it puts an irreversable magnetic spike on the heads. I have considered getting a true sine wave UPS unit just for demagging. If I were to get one I wondered if I should use it with AC power on and let it switch over if the power goes out or should I use it unplugged and use the inverted power for demagging. I think about these things everytime I demag and I am always relieved when I can turn off the demagger, I feel like I got lucky becuase the power hadn't gone out.

VP
 
Depends on whether it is the type which switches over with a slight break or not. I believe some are really permanent inverters with mains powered battery chargers, so that there is never a point when it's not using the inverter. That would be safe.

I've always had the same concerns about a power failure when demagging but after 30 or so years it still hasnt happened once. Must be lucky.
BTW aluminium parts arent magnetic as I understand so no need to demag.

Tim
 
Tim Gillett said:
Depends on whether it is the type which switches over with a slight break or not. I believe some are really permanent inverters with mains powered battery chargers, so that there is never a point when it's not using the inverter. That would be safe.

I've always had the same concerns about a power failure when demagging but after 30 or so years it still hasnt happened once. Must be lucky.
BTW aluminium parts arent magnetic as I understand so no need to demag.

Tim
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I have been looking at specs for the crossover time and the fastest are very expensive. Also I would want to look at the output with an O'scope to make sure it is a pure sine wave. I havent had the power go out either, but you just never know when it will happen. Aluminum is magnetic, it is ""Paramagnetic" it has a slight magnetic field that attracts the magnetic field.

Diamagnetism



VP
 
I have cleaned the heads and rubber rollers, I am always surprised to see so much black residue come off the rubber rollers. This must be the rollers themselves shedding? Also I found a lot of little spiral shiny metalic "thingies". They look like they are comprised of tape residue and metal. I have never seen these before, I suppose it is because I only found them on the (new) MS-16 were there is a level surface for them to collect. My other Tascams are all mounted upright so these things could fall to the floor.

VP
 
Forgot the photos

VP
 

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I don't believe power going out during a demag causes an irreversable magnetic spike.

As far as I was always taught ...... it will remagnetize the object it's near (head maybe) but it just requires starting over with the demag.
As far as I know it simply means you will have to do a really good demag on it ...... possibly a couple of times.

And I've done LOTS of cleaning on my reel to reels for 40 years and I have never seen anything like those curly ques before.
If they have metal in them then I have to think there's a problem there somewhere.
I don't find that normal at all.
 
Lt. Bob said:
I don't believe power going out during a demag causes an irreversable magnetic spike.

As far as I was always taught ...... it will remagnetize the object it's near (head maybe) but it just requires starting over with the demag.
As far as I know it simply means you will have to do a really good demag on it ...... possibly a couple of times.

And I've done LOTS of cleaning on my reel to reels for 40 years and I have never seen anything like those curly ques before.
If they have metal in them then I have to think there's a problem there somewhere.
I don't find that normal at all.
Click to expand...

All my Tascam manuals warn of this happening, I am trying to copy the page I just scanned. I cant seem to copy and paste it either. You will have to take my word for it for now.

I was looking at the curly things with a magnifying glass and it looks like tape residue with some fine metal dust stuck to it, I suppose it is normal wear from the tape lifters and such. If you look closely at all the metal surfaces you can clearly see that they are getting worn down, that metal has to go someplace.

VP

PS: This is a 15 ips 1" machine, what format have you had?
 
I agree that manuals DO warn of it...and lot's of Internet discussions warn of it...
...but I did read someone doing extensive tests (I will try and find it on the Internet) about the 3-foot rule and all those *warning*....and from what I recall about the article, it found that absolutely nothing bad happened when ignoring the 3-foot rule or the "proper" power on/off procedure of the demagnetize.

I still follow the "rules"...but I'm not that concerned about it. I mean, what are the odds of a power outage during that 2-3 minute process...??? Just don't do it on a stormy day! :D

I also notice that some "rules" tell you to bring the demag in/out for each piece and turn off between each, and then repeat the process....and others tell you to turn on the demag, bring it in/out for each pieces, but ONLY turn it off after ALL the pieces have had a pass.
I don't know how critical it is....I doubt it matters either way.

VP...what are you cleaning your rubber with?
If it's one of the "cleaners"...yes, you will get a lot of black/rubber coming off.
I use to use rubber cleaner once in a blue moon...just to "revitalize it", but found out that what was really happening was that the cleaner was slowly melting/eating the roller away over time, and that solvent can sink into the rubber and eat it away at the post even though the surface looks dry.
These days...I use just water to clean the rubber, and it seems to work better than any solvent. It takes a few extra rubs to get it clean, but it's safe, and the rollers look like new.

Check out Terry's Rubber Pinch Rollers and Wheels website...that's where I learned about using water to clean the rubber:
Terry's Rubber Pinch Rollers & Wheels
 
miroslav said:
I agree that manuals DO warn of it...and lot's of Internet discussions warn of it...
...but I did read someone doing extensive tests (I will try and find it on the Internet) about the 3-foot rule and all those *warning*....and from what I recall about the article, it found that absolutely nothing bad happened when ignoring the 3-foot rule or the "proper" power on/off procedure of the demagnetize.

I still follow the "rules"...but I'm not that concerned about it. I mean, what are the odds of a power outage during that 2-3 minute process...??? Just don't do it on a stormy day! :D

I also notice that some "rules" tell you to bring the demag in/out for each piece and turn off between each, and then repeat the process....and others tell you to turn on the demag, bring it in/out for each pieces, but ONLY turn it off after ALL the pieces have had a pass.
I don't know how critical it is....I doubt it matters either way.

VP...what are you cleaning your rubber with?
If it's one of the "cleaners"...yes, you will get a lot of black/rubber coming off.
I use to use rubber cleaner once in a blue moon...just to "revitalize it", but found out that what was really happening was that the cleaner was slowly melting/eating the roller away over time, and that solvent can sink into the rubber and eat it away at the post even though the surface looks dry.
These days...I use just water to clean the rubber, and it seems to work better than any solvent. It takes a few extra rubs to get it clean, but it's safe, and the rollers look like new.

Check out Terry's Rubber Pinch Rollers and Wheels website...that's where I learned about using water to clean the rubber:
Terry's Rubber Pinch Rollers & Wheels
Click to expand...

Well my power seems to go out on beautiful sunny days, that is why I am so concerend. I am using rubber roller cleaner, made specifically for pinch rollers, I get it from MCM electronics, I still have some of Teacs variety around also. You know, they sell you this stuff but who knows if it doing more harm than good. Terry's has a great business down there, he has been helpful in the past.


VP
 
Victory Pete said:
Well my power seems to go out on beautiful sunny days....
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That sucks....

Then go for the UPS. Most of the APC units I've used in the past don't "blink" during a power outage...that's their whole point...'cuz for computers, if they did "blink", you would lose your unsaved data, and that's what APC focuses on protecting.
 
miroslav said:
That sucks....

Then go for the UPS. Most of the APC units I've used in the past don't "blink" during a power outage...that's their whole point...'cuz for computers, if they did "blink", you would lose your unsaved data, and that's what APC focuses on protecting.
Click to expand...

Funny, I applied at APC over 20 years ago when they were in full production here in RI, they are still here, just no production! I looked at some of their models, I think I would get one that I would use strictly as an inverter, I dont want to chance the switchover glitch. I will need one with pure sine wave output. I also appled to Cherry Semiconductor also, there were a lot of high tech companies around here when I was studying Electronics, remember "Digital Equipment Corp"? But being an Electronics Tech playing in bars at night doesnt look good on your resume! Hence I ended up as a self employed Electrician/Electronics Tech.

VP
 
miroslav said:
Those are a bit more expensive. I think Monster also has 1-2 units with pure sine wave output.
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Yes but I think it is imperative to be a true sine wave. The magnetic field of the demagnetizer might rely on it.

VP
 
Oh I don't necessarily disagree, and I've had a few discussions in the past with folks using UPS boxes for *audio* gear...that ideally they should be true sine wave capable. For computers and what not....it's not important.

I was just commenting that the suckers are expensive compared to typical UPS boxes! :)
 
miroslav said:
VP...what are you cleaning your rubber with?
If it's one of the "cleaners"...yes, you will get a lot of black/rubber coming off.
I use to use rubber cleaner once in a blue moon...just to "revitalize it", but found out that what was really happening was that the cleaner was slowly melting/eating the roller away over time, and that solvent can sink into the rubber and eat it away at the post even though the surface looks dry.
These days...I use just water to clean the rubber, and it seems to work better than any solvent. It takes a few extra rubs to get it clean, but it's safe, and the rollers look like new.
Click to expand...

Victory Pete said:
I am using rubber roller cleaner, made specifically for pinch rollers, I get it from MCM electronics, I still have some of Teacs variety around also. You know, they sell you this stuff but who knows if it doing more harm than good.
Click to expand...
Funnilly, I've always used the iso-propanyl on the whole transport. The English DJ John Peel, used to say he just used spit on the pinch roller and that the iso-propanyl would dry and crack the rubber but in 20 years, that's never happened to me.
 
The rules are a bit conservative with some of the instructions I've seen just to keep people far away from any mishaps. Honestly I've usually done degaussing without a safety net though always having the fear of the power going out in the back of my mind like you mentioned. It's true you don't want the deguasser to break off mid-cycle when it's in contact or very near to the heads. It can produce a spike with a gauss level many times the normal operating level of the wand. It won’t always, but it is a possibility.

After years of just believing the power wouldn't go out, like that would only happen to other people :) I finally did break down and start degaussing plugged into a simple APC computer UPS. A degaussing wand is a very simple circuit with lots of wiggle room. You can use a modified sine wave type and there's nothing in the degaussing process that would be sensitive to any high frequency hash in the line.

If you want to put safety above all, yes just unplug the UPS and use the inverter for the whole process… and wear earplugs for the beeping. The worst scenario would be something like a quick on-of-on cycle in the power source, which is where you’d get the highest risk of spikes. Remember, you don’t even want to switch the wand on in close proximity to the heads, so there is some science behind it that justifies the warnings. This is one of those areas I’d rather be safe than sorry. It’s not a great inconvenience to take the precautions, so it’s a “why not” sort of situation.

You can demonstrate the phenomenon with audiotape degaussing as well. If you switch the tape degausser on while up against the tape you’ll hear a cyclic wow in the hiss when playing back the blank tape. When degaussing anything you want to introduce the device gradually for best results.
 
Beck said:
This is one of those areas I’d rather be safe than sorry.
Click to expand...

Yeah...the odds are on your side...but it's not a big deal to take the extra safety step if you want CYA 100%. :)

I wish I could find that stuff that some guy wrote up about doing on/off tests with a demag. He claimed there was nothing to fear...but again, it's easy enough to play it safe, so why not.
 
Victory Pete said:
Forgot the photos

VP
Click to expand...

What are you cleaning your rubber parts with? It is not advisable to use anything containing alcohol because it dries the rubber out. I've always used a rubber cleaner to remove tape shed/residue and keep the rubber pliable. When I start pulling off "black," I know I'm down to clean rubber.
 
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