No One Knows If This Actually Works

The TDK HD-01 Head Demagnetizer cost $22 in 1978, that's about $100 today. If you had the cash, there was a good reason to get one of these. Though it may not be the one you expect.

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[JanusCycle]

I get it, we all like having certainty, it feels comfortable and safe. But there is also value in uncertainty. Not knowing if the totem keeps spinning, or if it falls over in Inception (2010), opens us up to considering more possibilities. Being in that state makes us wonder about ourselves and the universe.

No one knows if the subject of this video actually works. There are ongoing debates and all sorts of tests that have been done. It's been over 40 years and there is still no definitive proof one way or the other. One thing is certain, many people did buy these. I think I presented a decent argument as to why that happened.

Thank you to everyone who decides to leave a comment. Even more interesting to me is the uncertainty surrounding all this. I think the way people choose to respond to this video tells us much more about the psychology of the person leaning the comment than we may realise. I appreciate everyone for watching. And even if I can't respond to every comment, I make an effort to ready every one, thank you.

[rayoflight]

I had one of the TDK demagnetiser cassette, the exact model you show in the video.
The magnetic flux generated by the cassette is minuscule when compared to the wand-style, classical demagnetiser, but the frequency isn't 50 / 60 Hz, but it is in the audio band. The flux generated by the cassette is 100 times higher than the field induced by the rolling magnetic tape.
I conducted some tests with the TDK demagnetiser. You can verify its efficacy with a CrO2 reference tape with a 10 KHz note. The amplitude of the output is 15 - 20% higher after 4 or 5 demagnetisation pulses with the TDK cassette.
This is because a magnetised head core (caused by playing CrO2 and Metal cassettes) limits the reproduction of the higher frequencies.
By the way, it is difficult to evaluate the functionality of the TDK demagnetiser without proper instrumentation, because the ear can't pickup a 20 dB difference at 10 KHz or more.
All in all, yes, the TDK demagnetiser works. It is useful? In a professional setting, where the audio equipment is properly calibrated, yes.
As last note, the TDK demagnetiser cannot recover a magnetic head after an accident - when somebody intentionally put a magnet in contact with the head. You need a wand in that case.
Regards,
Anthony

[ScottGrammer]

A magnetized head erases highs from your tapes as you play them and it increases noise when recording. Not long after that TDK demagger came out, I tested it using a gauss meter to see if it actually reduced the magnetism of a magnetized head. It did next to nothing - too weak. A real demagger reduced the field to below what the meter could read.

[Taketimeout]

A man who speaks the truth. I had one of these back in the day and I never noticed it making any difference whatsoever. It's as noticeable as having one extra hair on a broom, ie, no difference whatsoever.
But they did look cool.

[Raptoraus]

I was lucky enough to find a new in box Realistic tape head demag which I used to sell while working at Tandy's back in late 80's :) I have used mine once on a Sony CFD-5 boombox (first with a CD player built in the D-50) It had a lot of hiss and the demag really helped other than that it has not been needed. There is a guy I have dealt with from Romania his name is Segui and his name on Tapeheads is magnetic Blood. He restored my AIWA PX10 walkman and I he recorded some albums for me (Queen, Australian Crawl, 1927 Ish and others) onto 2 x TDK SAX-90 chrome tapes using one of his very high end tape decks ( Nakamichi or Revox) Playing in my AIWA PX10 and Sony DD9 Walkman they sound fantastic. Better than the cd version.

[jeffreyyoung]

I have been servicing tape decks for several decades, and I have a 110VAC demagnetizer I use every time I clean and service a deck.

Most people will not notice the degradation over time, but it is a reason their tapes go bad. Yes, there is a hiss that can be heard when the head is magnetized, but the magnetization can cause the tape to be erased over time while it is being played, and in the end, the tape will be unplayable.

These cassette tape demagnetizers were sold to do what the AC units did, but they didn't get the job done, if the head was seriously magnetized, and was the reason I kept my AC unit.

[lachlanlau]

Love the narration and the cinematography! So relaxing!

[TBNTX]

Speaking for me, I still have my TDK HD-01, It works well to de-magnetized the tape heads on my decks, but one still needs to remember to clean the heads, the capstan and the rollers.

Also, be sure that you have turned off the audio. This makes a horrible noise if you use it with the sound turned on.

[albertocabezas]

The first sound equipment I bought was a Sony double cassette + CD player. I played tons of tapes there but after some time, the recordings were being poorer and poorer no matter I cleaned the heads. Once I made an experiment erasing a whole tape. Curiosly the next recording I made wasn't too bassy, noisy and limited crunchy trebles. That was the time I read about residual magnetism on tape heads. I bought the same TDK model at a local flea market (more or less five bucks). At first, I didn't note any big difference in sound quality, except the noise floor was reduced substantially but recordings were improved 100%. After many years educating my ears and playing tapes I can assure you this little machine does its job and it worths every cent you spent on it.

[OneHitWonder]

I had one of these! Used it on my expensive cassette player and I _still_ have no idea if it did anything or not. Sounded the same before and after.

[stvlu]

Some cassette decks made by AIWA had automatic tape head demagnization built into the tape deck. All you had to do was power it on, and the process was done in seconds.

[spacemissing]

I have two HD-01s. The older design, I believe, is better made, but both work.
As for how much good they do... I'm not sure. Can't hurt anything, though.
The clear housing is of little significance to me other than that it shows the parts.
Otherwise a person might not be convinced there was anything functional in it.

[davidbartley]

I have owned this since 1980, and it does in fact do what it promises. Head demaging should be done periodically along with a thorough cleaning of the heads, tape path and pinch rollers. Once magnetization reaches the point where there is an audible loss of high frequencies - it is too late. The magnetization has already diminished the sound quality of recorded music. Do it about every 100 hours of paying time, more frequently if the deck is used principally for recording. Replace the battery when the red light appears dim or after three years if the cartridge has not been used recently. The TDK demagnetizer uses an A76 or type 357 battery if I recall correctly.

[cars]

It does work, They had two models the HD-01 and the later unit the HD-30 that worked better for decks with logic controls. I tested the HD-30 by magnetizing the tip of a small screwdriver and then pushing the tip of the screwdriver to activate the HD-30 and yes it WORKED the screw driver WAS TOTALLY DE-MAGNETIZED.

[xanataph]

It's not needed very often with a domestic cassette deck. Cleaning the heads frequently is what makes the biggest difference. Also, aligning the head is sometimes makes a massive difference, especially on machines picked up second hand. The mains powered hand held demagnetizers probably do a better job, but in some cases they can be difficult to get near the heads of certain cassette machines.

[ChronoTango]

Just recently had the chance to see this exact TDK demagnetizer. Very cool and interesting indeed.

[ddnava]

I think the transparent look is so people can easily recognize they're not regular casette tape in case the stickers peel off

[oswaldjh]

Having used one I put this in the category of the $100 HDMI cables some vendors try to push today.

[sophiespaan]

This, to me, screams that it wants to be the heart of a hacked-together kick drum synth.

[stvlu]

I remember Radio Shack had one demagnitizer that had a permanent round magnet in it that was rotated by a cloth tape that also cleaned the heads. I think these did more harm, magnitizing the head than removing any. It made a weird rumble sound over the audio out that sounded like the traveling cylinder space probe in Star Trek 4, which I really think where they got the sound effect from lol.