Magnetic tape demagnetization is critical in recorder/players and for new recording on previously-recorded tape media

[EERecordist]

In my recoding career we were a 1/4", and 1" shop, pre-digital. I'm 1/4" at home.

For best results it is a good idea to erase tapes, unless they are fresh from the factory, before recording on them. The theory is you turn on the eraser switch power on the demag, we used at 3 feet, move in from there, back it out by a few feet, then only then switch it off. The tape path magnetic alloy parts become magnetized by the passing of magnetized tape. That is the guides, lifters, metal capstan, and the heads. Same, you need a powerful enough demag tool, fade it in, move it around, and fade it out. It applies to cassette recorder-players too.

We were operating on 60-70's lore, from peer lead professional studios, so YMMV. We were taught a specific hand-waving technique with our demagnetizers for the tapa path and bulk erasing,

I came a across this 2" pizza oven demagnetizer video. I had not seen that machine. So this is for ASR curiosity.

93K views · 4.3K reactions | @wyclefjean doin' his thaing!! Erasing the tape before we go into a session tracking some sweet drums to some sweeeeet songs! Also demagging the tape machine heads and (not shown!) cleaning them... More about this session

@wyclefjean doin' his thaing!! Erasing the tape before we go into a session tracking some sweet drums to some sweeeeet songs! Also demagging the tape machine heads and (not shown!) cleaning them......

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[MaxwellsEq]

That looks familiar. I'm fairly sure our music library had a few of those.

 

[Palmer]

Previous employer sold older tape stock, Beta, DigiBeta and so forth - and had one of those. We had to run everything through it, at least twice.
Not good if you have a pacemaker, though...

 

[DVDdoug]

I think I had a bulk eraser. It would have been a consumer unit for 1/4-inch tape or cassettes. But I didn't use it everyday. The erase head worked fine! And I was mostly recording viny to tape/cassette and I didn't often re-use tapes.

I did have a demagnetizer for the tape heads, etc., which was sort-of a short "wand".

 

[MRC01]

I still have my old plug-in wand tape head demagnetizer. It's also useful for demagnetizing other objects like wristwatches.