No, they are not. Using a 115V demag on 230/240, you run the serious risk of burning the coil.
Thoughts on using Tools or Watch demagnetizer for my Reel to Reel machine degaussing?
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Its just the same as plugging a 115v transformer into a 230v outlet ,
do not do it !
As far as having a switch on the device itself , not a good plan ,
just having a direct plug in connection means less chance of magnetising something inadvertantly , and in any case you have to move the device away from the equipment to de-energise it .
A machine with parts in the tape path that have become magnetised can seriously degrade pre recorded tapes ,
In short if you pick up an old tape machine second hand , dont even think about playing precious old recordings on it until your satisfied its been demagged otherwise you might end up with degraded FR as well as odd noises superimposed on the music .
I remember a few years back I degaused my Watkins Copicat , the difference was night and day ,
way more signal level off tape , better FR , less distortion and noise .
do not do it !
As far as having a switch on the device itself , not a good plan ,
just having a direct plug in connection means less chance of magnetising something inadvertantly , and in any case you have to move the device away from the equipment to de-energise it .
A machine with parts in the tape path that have become magnetised can seriously degrade pre recorded tapes ,
In short if you pick up an old tape machine second hand , dont even think about playing precious old recordings on it until your satisfied its been demagged otherwise you might end up with degraded FR as well as odd noises superimposed on the music .
I remember a few years back I degaused my Watkins Copicat , the difference was night and day ,
way more signal level off tape , better FR , less distortion and noise .
Yes, and with a little research and experimentation . . . .One word of warning with the vintage style tape head demag ,
it often has an exposed metal pole piece ,
You do not want this coming into contact with the head surface especially , but any metal on metal contact is to be avoided , in the studio a demag always has the pole piece wrapped in some cotton cloth . It will readily cling and buzz to magnetic materials as previously mentioned .
Dont bother buying a vintage demag ,
get the one on Ebay , and when your girlfriend asks for an explanation to why you have a sex toy on the bench you can send her away with a little twinkle in her eye and a blush on her fanjita
I used a coil on it's frame from an old electic clock motor which worked fine.
The trick is to pull the demag away from the machine slowly and far enough that when you turn it off it leaves no magnetic imprint. When the AC is interrupted on a sine wave peak the collapse of the field puts out a rather nasty magnetic spike which you don't want anywhere near the tape machine, tape or a hard drive, etc. And you can't time your off switch with 60 cycle AC.
BTW, thinking about it, a .1mfd 400 v cap in series with a 10R 1Watt accross the coil would allow it to die out a nice ringing way.
The trick is to pull the demag away from the machine slowly and far enough that when you turn it off it leaves no magnetic imprint. When the AC is interrupted on a sine wave peak the collapse of the field puts out a rather nasty magnetic spike which you don't want anywhere near the tape machine, tape or a hard drive, etc. And you can't time your off switch with 60 cycle AC.
BTW, thinking about it, a .1mfd 400 v cap in series with a 10R 1Watt accross the coil would allow it to die out a nice ringing way.
Yeah, I've soldered using a candle-heated nail stuck in a broomstick, but I prefer my wtcpt. Working professionally, the proper tools always pay for themselves. Demaggers as designed direct the field for a purpose different from a recycled solenoid or motor.
Man, that Ampex is so ugly it's beautiful! Hopefully designed for function over looks, and they are hated price wise (nice and cheap). Should be good up to a 1/2" machine, and it IS Ampex. I don't know how it's 7W compares to the Handi, and those double-squid fins, I wonder what the end field profile looks like. . . Depending on the metal inside the plastic, it could also be used for self defense.
I always power up/down six feet away and support my hands on the deck for stability when I get in and slowly move across the path, up and down greater than 1/4". No "floating holding" during a demag because of the ferrous pull mentioned above.
Mike
Man, that Ampex is so ugly it's beautiful! Hopefully designed for function over looks, and they are hated price wise (nice and cheap). Should be good up to a 1/2" machine, and it IS Ampex. I don't know how it's 7W compares to the Handi, and those double-squid fins, I wonder what the end field profile looks like. . . Depending on the metal inside the plastic, it could also be used for self defense.
I always power up/down six feet away and support my hands on the deck for stability when I get in and slowly move across the path, up and down greater than 1/4". No "floating holding" during a demag because of the ferrous pull mentioned above.
Mike
I always believed it affected S/R primarily and HF loss secondly, so I'm wondering how it causes clicks?
It’s a guess but I think because it randomly changes the polarity of some magnetic domains. Like a DC offset.
The passage of tape over heads over time causes a residual magnetic field buildup - in reel to reel machines I used in studios we always degaussed the heads at least weekly.
The small tipped demag units designed for 1/4” heads are not so suitable for the multitrack heads as they lack the power and tip size needed. The Han-D-Mag kit came with a demagnetiser, a pocket magnetometer (Gauss meter) plus soft iron strips for testing for mag buildup. The tip is coated with a plastic cover - metal must never come into contact with the heads, capstain or guides or you’ll get scratches. DIY degaussers are usually inferior as they don’t have a properly profiled demag tip - the shape of the tip works to guide and concentrate the delivered mag field.
The process was to turn on the unit well away (2M is plenty) from the tape deck with all tapes at least 3M away (we never did it with the tapes in the control room anyway) and bring the tip to the head being demagged and running it back and forth across the surface gradually pulling away while still using the same back and forth motion, repeating this three times then moving to the next head, tape capstain and tape guide posts. This slowly collapsing alternating mag field leaves the heads in a magnetically neutral state.
Stainless steel as used in tape guide posts contrary to popular belief can become magnetised. Tape heads, (especially the playback head which gets the mast magnetic buildup as it doesn’t get the high frequency AC bias or AC erase signal as do the record and erase heads), are all made from magnetically permeable material and so are prone to static mag buildup from tape passage - retention depends on the materials used in their construction but it does occur.
The small tipped demag units designed for 1/4” heads are not so suitable for the multitrack heads as they lack the power and tip size needed. The Han-D-Mag kit came with a demagnetiser, a pocket magnetometer (Gauss meter) plus soft iron strips for testing for mag buildup. The tip is coated with a plastic cover - metal must never come into contact with the heads, capstain or guides or you’ll get scratches. DIY degaussers are usually inferior as they don’t have a properly profiled demag tip - the shape of the tip works to guide and concentrate the delivered mag field.
The process was to turn on the unit well away (2M is plenty) from the tape deck with all tapes at least 3M away (we never did it with the tapes in the control room anyway) and bring the tip to the head being demagged and running it back and forth across the surface gradually pulling away while still using the same back and forth motion, repeating this three times then moving to the next head, tape capstain and tape guide posts. This slowly collapsing alternating mag field leaves the heads in a magnetically neutral state.
Stainless steel as used in tape guide posts contrary to popular belief can become magnetised. Tape heads, (especially the playback head which gets the mast magnetic buildup as it doesn’t get the high frequency AC bias or AC erase signal as do the record and erase heads), are all made from magnetically permeable material and so are prone to static mag buildup from tape passage - retention depends on the materials used in their construction but it does occur.
Maybe was at the junction of the loop where tape is joined - magnetisation of any part would cause this as there would be a departing and entering polarised magnetisation of the joint edges if it occurred after erase/record heads.
"running" might not be the best description as it should be a very slow travel across the entire tape path, and since the field is already vibrating at 50/60Hz I never felt the need for me to do any 1Hz "back and forth" funny stuff. Everyone has their own education, I learned from one of Les Paul's techs, and the procedure was verified by mentors along the way. Lets just do it!
Demag a Tascam 52 (clean the path completely first): Plug in 2m away, slow 3-5 sec approach to the left roller, Handi in both hands tongue curve down, butt of hands on the head block, approach roller from above, always maintain a 5mm/.25 inch proximity throughout, slow down-up-over-down the left roller, slow away from roller, slow out .5 m away to move hands, slow approach tongue curved up, hands on the deck to left lifter at bottom, slow up-down, slow past the erase head, slow past the guide, slow past the rec head, slow up-down on the stabilizer, slow up-down on the right lifter (with a Handi I would do stab. and lift. in one shot, with a weaker demag individually), slow past the play head, slow past the tape guide, slow up-down on the pinch roller, same with capstan, away .5m as above to re-position hands on the head block, do the right roller tongue down as above, slowly move Handi away 2m to power down you're done. NgggGUGH! Whew! that was an awesome <3 minutes! You know what "they" say, if you love what you do for a living, you will never work a day in your life.
Remember to clean the tape path again after de-magging. I recommend Athan pinch roller cleaner and pinch rollers when needed. In a "pinch" I use 1 drop of clear dish liquid in 1oz of water. Prefer twill wipes for rubber/urethane cleaning, rolling on a clean piece of paper.
Common sense prevails regarding proximity, keep at least 4m from hard drives/storage, at least 20m from any tape stock or recorded reels, use your "head". No outboard or console issues really.
Mike
Running being just an expression - maybe closer to an extremely slow wave - to cover the whole area of tape head or guides as these were 24 track machines and the heads, guides and lifters all much larger than the demagger tip. We were originally shown by an MCI rep and also by a Studer tech (from Studer) in another studio. This was always done prior to doing the calibration procedure on the Studer A820 (playback and record software cal)
Steven Paris
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"..... slow down-up-over-down the left roller, slow away from roller, slow out .5 m away to move hands, slow approach tongue curved up, hands on the deck to left lifter at bottom, slow up-down, slow past the erase head, slow past the guide, slow past the rec head, slow up-down on the stabilizer, slow up-down on the right lifter....."
And DO NOT forget to swing a live chicken over your head in a counter-clockwise direction whilst doing this!!!
And DO NOT forget to swing a live chicken over your head in a counter-clockwise direction whilst doing this!!!
