Tape head demagnetization

A magnetized head will cause loss of high frequencies long before there's a drop in volume.

The deck probably has some other problem.

My initial thoughts are that tape heads that need demagnetising do not generally exhibit the kind of extreme symptoms you are experiencing.

I would forget demagnetising as a solution right now, and try and establish the real cause of the dramatic loss of level.

Gareth.

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Thanks Bill and Gareth,

OK - that's two votes against demagnetizing, plus I was skeptical myself. So, now I have to decide whether to move my tapes to CD's, or tear into a 10 year old car radio/tape player /cd player. I think it will be easier to move a few tapes to CDs than tear up the car radio.

First check the tape on a known good tape player. Or use a original prerecorded tape.

Tapes recorded on a machine with bad aligned heads will play good on that machine, but not on others.

Clean the head. Clean the tape guides. Demag if you can. Adjust the head in height for maximum output. Adjust the head azimuth to maximize high frequency. And repeat the last two.

A magnetized head will destroy all your tapes (bad signal to noise ratio). And can not be undone.

You could of course convert your tapes to high quality mp3, and fit them all on a single CD or SDcard, which could then be played on just about any cheap slot-in replacement for your original car player with far better results than you have now.

Gareth.

loss of volume? doesn't that mean gunk building up that keeps the tape too far away form the head? Or, mean some component is lost? like a coupling cap that has seen better days? Or, something as simple as one of the wiring connections in the cabling has gone high resistance.

Sadly, my favorite tapes were made during the era of poor mylar coating and have all turned 'squeaky' and unplayable! I wish I could have transferred them before they died, but hindsight.

I'd give up on head demagnetizing. It's not likely the problem. And you're more likely to magnetize it with the demagnetizer unless you disassemble the thing so you can get at it.

Tape players don't last in cars. I've only had two CD players and they were worse. The heat, outgassing of plastics, dirt, etc. get all over the optical and mechanical stuff. Luckily, my last player has a USB slot and a Flash Card slot. It won't play a CD any more, but the SD card works fine.

As for old tapes... If you have rare music, you're pretty much screwed. If you have popular stuff, there's an option. Go to the library, check out a CD. Copy it back to the tape. If you bought the tape, you own the license to play it. The nitpickers will argue about it, but I think you're on solid moral and legal ground to refresh the media.

Sounds like very dirty heads , or head alignment has gone out of whack. This happens when one or both head mounting screws loosen. Happens occasionally.

Mark Z.

On Sat, 24 Nov 2012 16:35:30 -0800 (PST), Robert Macy wrote as underneath my scribble :

A trick I found for this squeaky problem to do a one time transfer was to play them as cold as possible, unfortunately just freezing the tapes doesnt last long enough - always thaught a head heatsink to a deepfrozen al or cu block might do the trick but I never tried it!! I just caught mine early enough! Mine were BASF :(

As others have said, this does not appear to be a magnetised head but it could be that particles from your tapes has collected in the gap(s) on the the tape head(s). The gap(s) need to be magnetically open so that the passing tape completes the magnetic circuit and it is a very small gap on a playback head (of the order of 0.0001 inch).

BTW, if you are using a head demagnetiser never switch it on or off anywhere near the heads. Move a few feet away before switching off. One spike and you will have magnetised them!

Many years ago I worked in the dev lab of Marriott Magnetics one of the original makers of tape heads in the UK. Long gone.

Charlie.

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Try this method. Put a "squeaky" tape on a metal tray, and put it in a 150 degree oven (NO HOTTER!!) for about

1 hour. It will reactivate the binders and lubricants and when you play it, TRANSFER it to another medium on first play. Works for old reel to reel tapes. Google is your friend.

I'd clean the head and capstan first, then worry about degaussing things.

Once upon a time i had a battery powered cassette sized tape head demagnetizer. Sounds like just the trick for your situation, to determine if it is head magnetization (perhaps unlikely) or some other problem.

?-)

Lucky you are, over 200 to transfer have i.

?-)

existing

under/inside

Depending on your tastes, some might be available now in CD or MP3 format. You may have to buy a lot more than what you have to get all you want. I have a lot of old music of the 1950s to 1970s range and an interesting bit outside that range. Not all digital yet. You know how to find me.

?-)

.

This

occasionally.

(+1) on the dirty heads. I had forgotten.

?-)

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Wow! Great tidbit!

I don't know if it's the same problem you're referring to, but I do know that a lot of reel-to-reel tapes made several decades ago suffer from a problem known as "sticky-shed syndrome".

There's no permanent cure, but it's often possible to restore such tapes to playability (at least temporarily) by removing moisture from the tape/binder. This can be done by "baking" the tape at an elevated temperature, or by storing the tapes in a temperature-and-humidity- controlled environment for a period of time.

Some people have tried lubricating the tape just before playing it (with alcohol, and I think I've heard of people using a light silicone oil as well).

You might want to select one or two "sticky" tapes, and then doing a gentle bake (possible heat-and-time schedules are in the Wikipedia article), or put them in a sealed Tupperware container with several large (and recently-baked) silica-gel moisture-absorbing packs for a month or two. See if getting the absorbed moisture out of the binder restores the tapes to a playable condition... if so, play them and digitize them!

I had the master and mix tapes for an album my wife recorded in the late 1970's baked and transcribed, some years ago... the process worked and we were able to recover the album and transfer it to CD. Without baking, it would have been a lost cause, I think.

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On Sat, 24 Nov 2012 14:27:55 -0800 (PST), "hr(bob) snipped-for-privacy@att.net" put finger to keyboard and composed:

Just to offer a different perspective, I onced repaired a Fujitsu Ten auto-reverse car cassette player with the same symptom as yours. The problem turned out to be a small dirty multipole switch. I'm a bit hazy on the details, but ISTR that there were two head circuits, and a different circuit was selected in forward and reverse mode.

As for demagnetising the head, I have a cassette tape with a built-in battery powered demagnetiser that automatically activates when you press the play button while the player is unpowered.

It looks something like this ...

- Franc Zabkar

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