Discussion about vintage cassette tape degradation

Hi Werner and welcome to Phoenix.
Once recorded a That's CD-MH at type IV position on an AL-300.
It was possible to calibrate it at type II position but doesn't sounded good, so I tried type IV, calibration worked by reducing the bias close to minimum and that('s) sounded better.
I think rec eq peaking made the difference.
 
Werner said:
What are you sniffing, actually? A crayon smell is typical for chrome. Maxell have not made a chrome tape since the 1972-1975 'CR' model. Since then, starting with UD-XLII, all were ferro-cobalt. As most other Japanese manufacturers did.




Barring extreme storage conditions ferro-cobalt in general ages rather well, although some heavily polished tapes (post-1986, generally) are prone to mechanical surface damage.

And what is this with 'hard biasing'? When deck and tape are healthy, and the tape lies within range from the deck's central biasing point, then it works, end of.




It has been conclusively proven in the past few years that chromium dioxide, as used in tapes, is chemically instable and decays with time, even when properly stored, resulting in signifantly aberrant recording parameters and performance: treble sensivity goes down, MOL goes down, distortion over the top 10dB range goes up, compression goes up.




HD8 is a metal-enriched ferro-cobalt. Just like the few others of this breed (TDK, That's) it is characterised by abnormally high sensitivity, high SOL, and high bias noise, pushing it far away from regular IEC type II behaviour.
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I know the smell he’s talking about, I have more than likely the same mid 80s Maxell XL II tapes, and although they’re not pure chrome, they definitely have that smell like the BASF chromes. Although I understand chromium dioxide is odorless, it’s one of the precursors/chemicals used. So those Maxwell tapes which I assume are ferric cobalt, probably used some of the same chemicals in the process. I know someone mentioned that they don’t remember that crayon smell when these tapes were new.

Mine are hit or miss as to whether they bias correctly on both of my 3 head decks, but I can get 7 out of 10 of them biased correctly. It seems my BASF chromes, and TDK SA tapes aged better, but of course everybody’s experience is different. Definitely not perfect on 40+ year-old media, but much better than the new media in my experience.

One of my favorite tapes are the Maxell XL IIs tapes, they still sound phenomenal and maybe because they’re not quite as old. Also my TDK SA tapes have aged very well, and still bias easily, they are tough to beat for sound quality IMO.
 
20tajk7 said:
Once recorded a That's CD-MH
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I have a That's EM-X which is a similar type II metal tape. It calibrates correctly and sounds fantastic at any of my Technics decks, as a type II (these decks are auto-sense). Maybe it's deck depending.

The later TDK-SA and SA-X are notorious for railroading. It has been proven that the problem lies in the cassette rollers. Usually, the line doesn't affect the sound but sometimes it affects the calibration, especially the sensitivity's balance.

I haven't came across any type II that degraded through the years except one: a TDK-SA Black Limited that suffered from binder breakdown. I treated this tape with silicone lubricant and it has quite stabilized.
A few real chrome I have still sound and calibrate good (actually they sound extremely good - better than any ferric-cobalt I have) but in the expense of the dropped sensitivity/levels.

I believe (my personal opinion of course) that the cassette is a very robust format. I had stored my mixtapes and my CD-rs for more than 6-7 years in a cabinet exposed to the weather conditions, at my balcony. The tapes survived without any sign of abuse; the CDs didn't...
 
Yes, that's why I went to cassettes tapes back in 2008, found a TDK D on the dashboard of my old father's van, ten years in sun and humidity it still plays, while properly stored cd-r's are unplayable after one year...
 
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That s not been my experience with CDRs. I have some burnt over ten years ago that play like day one.

Are those CDRs burned to redbook standards or something else?
 
Mostly burnt with computer using Nero at the lowest speed (on Windows 98SE, that was long ago).
By the way I still have a few cd-r's still playable, all Verbatim AZO burnt on an IMac or a Philips hifi cd recorder.
 
I used mostly TDK Metallic Disk due to being ready available and cheap at my location, that time. I used a Ricoh mp6200s (a scsi writer) at 2x. Circa 2000. Every cdr that was taken care of, still is readable. But the cdrs that were stored in that cabinet, almost all have some unreadable sectors. All red book, written with Easy CD creator or Nero. My data cdrs suffered more.

I still have this writer (and the entire win98se computer) fully working and I still use it for my mix cds, when I don't want to use CD-Text (not compatible). Although it doesn't have a sort of burn proof, the failure rate is extremely low.
 
I’m wondering if you didn’t get a bad batch of CDR’s?! There is some kind of a phenomena known that the coating actually starts coming off or degrading. I’ve also heard that they should be stored upright like an LP so they stay nice and flat. I can’t see them really warping unless they were exposed to heat while stored horizontally. My 2 cents.
 
My CDRs with photo scans are holding up fine after 25 years. I think some of them are some HP rebranded cheapos, even. Temp and humidity is somewhat controlled in my basement but not perfectly. Still need to get that software to get those images off of my Kodak ProPhoto CDs, though.
 
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