The Magnetic Tape Viewer - see the sound on a tape

An intriguing piece of retro gadgetry that lets you view the magnetic patterns recorded on tape.

Special thanks to Andy on Twitter who first made me aware of this device back in 2016

FAQs
Q) CAN IT SEE WHATS ON A FLOPPY DISK?
A) No - It didn’t show anything on a 5.25” floppy I tested (BOTH SIDES)
Considering the viewer is pretty much maxed-out for resolution by an 8 track, (8 tracks recorded on a tape 1/4” wide at 3.75 ips) I’d imagine that anything more dense than this will be beyond the capabilities of what can be displayed by the device. I’ll try an 8” disk soon - but I would be shocked if it shows anything for the same density reasons

Q) You can buy these sheets of magnetic viewing paper that do the same thing.
A) They don’t have the same resolution or sensitivity - at least the ones I’ve bought don’t. They can’t show the magnetic signal and track layout on a tape. Nothing registered when I tried.

Q) You can use this fluid stuff that does the same job
A) A few people are mentioning various ways to do this with a liquid smeared on the tape - These were known about - and likely made by 3M as well - but one reason for the development of the magnetic tape viewer was that it was a ‘non destructive’ way to read the tape - here’s an except from their patent application where they mention one of the existing and alternative methods to do the same thing.

“Heretofore magnetic signals recorded on magnetic tape have in a sense been rendered visible by smearing finely divided ferromagnetic material over the tape and allowing it to migrate to points of maximum magnetic flux. Besides being slow and messy this procedure involved the greater disadvantage that thorough cleaning of the recording medium was required to prevent the applied ferromagnetic material from supplying false signals. This procedure is treated in the television industry as unacceptable for the splicing of magnetic recording tape and splicing has instead been confined to tape areas in which the picture is blanked out.”

Q) Who is the voice in the Datsun Commercial?
A) Danny Dark

Q) What’s the white pad on the left for.
A) Thats the ‘Viewing Pad’ - to see a picture of it being used - freeze the video at 02:51

Q) What’s the spectrum analyser to the left of the Reel to Reel?

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[Techmoan]

*There’s a bit more information in the video description text box.*

[Jamato-sUn]

"You're probably not wondering that, but I'm gonna tell you anyway" — that's the attitude I love this channel for.

[Nostalgianerd]

This blows my mind. Seeing the series of simple lines that make up such complex sounds.

[schoggi]

The logo displaying when you put it in the case is a brilliant idea!

[Breakfast_of_Champions]

I'd never have thought that the magnetic field on tapes is strong enough to move a ferrofluid.

[brodysdaddy]

Techmoan: This device lets you see sound.

Me after hearing voice actor clip: Never mind that shit, I gotta get a Datsun Z!!!!

[moofymoo]

6:30 - if Duke Nukem is telling that I need that car, I need it!

Now this is a gadget I never knew it existed. Thought this can't be achieved without electronics, yet here it is. Fascinating.
Great video as always, thanks!

[joeperez]

I'd never seen this specific implementation. Very interesting.

Back in the early era of 2" Quad video recording, a similar technology existed for use by video editors. At that time, videotape was spliced with a razor blade and adhesive tape, much like film or 1/4" audiotape. A liquid solution (Edivue was one common brand) was brushed onto the tape, and from this, the editor could see the location of the sync pulses and the vertical interval, allowing the cut to be made precisely on the interval, and maintaining the proper distance between adjacent frames so that the machine would play smoothly across the edit point.

Personally, I don't miss those days.

[SteveMallison]

I've never seen a device like this before, but it takes me back to the early days of videotape editing. The tape was 2 inches wide and edits were made by physically cutting the tape using a specially designed editing block. Very fine magnetic particles in a volatile liquid were applied to the tape to make the "edit pulse" recorded on the control track visible so you knew where to make the cut, which had to be in the vertical interval. The two ends were joined with a special sticky tape. Thankfully electronic editing soon made this obsolete but it was still occasionally used to repair a damaged tape.

[CannonKnight]

Not sure whose voice I like more: Techmoan's classy British accent or the deep, groovy voice on that Datsun Z advert. Tough call.

[blautens]

Pre video: I have absolutely no legitimate need for this.
Post video: I must have one.

[SlideRSB]

I use a reader similar to this one quite regularly at the audio facility I work at. I'm an audio engineer and I specialize in archiving older media formats for preservation. Many times, I will get tapes and magnetic film with minimal or no documentation which makes playing them back properly difficult. The magnetic tape viewers I have at my disposal is a big help in that regard.

[doug]

This is why I love this channel - I get to learn about things I never even knew existed. Well done as always.

[carymundy]

I believe these were originally used to assist in cutting and splicing the 2 inch quadruplex video tape that was used in the 1950s all the through early 80s. One could achieve a jitter-free physical (!) splice if the tape was brushed with a ferrous oxide fluid to “develop” and view the magnetic pattern on the tape. This allowed the editor to make a precise cut at the blanking interval used for NTSC. Of course brushing anything on the tape caused it’s own problems, and back then electronic editing was unknown. 3M was the dominant supplier of quad tape. This was their solution to customer’s editing problems.

[wwsvs]

Fantastic video as always! That tape of VO artists contains many who worked in animation. Danny Dark was Superman for Hanna Barabara's Super Friends and later the main voice of the NBC television network. Michael Bell was Zan from the same show. Bob Ridgley was Tarzan: Lord of the Jungle and Thundarr the Barbarian. Walker Edmiston was on many of the Sid and Marty Kroff shows and featured in Land of the Lost as Enik. Lennie Weinrib was Commissioner Gorden in the New Adventures of Bat Man for Filmation. Oh and Richard Baseheart and Rober Brown and Bob Holt and... I could go on and on as I see many more I recognize, but that is one really great tape!!! It would be fantastic to hear the full thing. Keep up the great work!

[Roland_Tr_Swing]

This was useful for tape splicing in studios back in the day

[manonthedollar]

I love all those finishing touches -- the wooden box, the magnetic 3M logo, the overall solid construction. Man.

[soulchorea]

So fascinating! I love the actors tape; stuff like that makes me wish I was an archivist that could make sure little random things like this are preserved forever!

[MrWombatty]

Probably just as hard to find one of these in good condition as finding a mint-condition Datsun 240/260Z!