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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 1st Dec 2022, 1:59 pm   #1
Martin Bush
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Default Pure Chrome tapes

Hi all

I am considering trying out a pure chrome tape on my deck, but have read that your deck needs to be properly calibrated to record on pure chrome, or else the recording will sound duff.

I have a Yamaha deck that has an automatic feature which sets the bias - I think it records some test tones and adjusts until they are correct. It also has a bias adjust control which, to be honest, I have not done much with due to it having the auto feature.

So, my question is, is that what is meant by having a deck that is calibrated to work with pure chrome cassettes?

As I have said in other threads, I am perfectly happy with ferric tapes, but it is always interesting to experiment.

Martin
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Old 1st Dec 2022, 2:10 pm   #2
paulsherwin
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Default Re: Pure Chrome tapes

Calibration is primarily about bias levels, though tape sensitivity is a factor too. 'Real' chrome tapes like BASF Chromdioxid will typically be overbiased by a deck calibrated for a pseudochrome tape like TDK SA. The Dolby tracking will also be out.

Decks which autocalibrate should cope with the differences to a greater or lesser extent.

Almost all Japanese decks were factory calibrated for Japanese tapes, usually TDK SA or Maxell UD-XL II in the chrome position. A few European manufacturers like Eumig calibrated to BASF Chromdioxid. BASF stuck with proper chrome even though very few decks supported it well, and never sold a pseudochrome formulation.
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Old 1st Dec 2022, 2:44 pm   #3
Martin Bush
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Default Re: Pure Chrome tapes

I have some used BASF tapes, but I was looking at a NOS tape and trying that. Perhaps I'm best just using my used ones.
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Old 1st Dec 2022, 3:03 pm   #4
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Default Re: Pure Chrome tapes

As Paul says, they will not match most decks set up to use pseudochromes - which most are. You'll get a very poor frequency response. Otherwise later decks with auto calibration (as you have) should cope. But 'experts' such as Angus McKensie and many others were not fans of pure chrome tapes anyway for a variety of reasons, pseudos such as TDK SA generally being much preferred. I personally would not get 'involved' with pure chrome tape.
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Old 1st Dec 2022, 3:26 pm   #5
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Default Re: Pure Chrome tapes

Pure chrome tape generally has lower sensitivity but lower noise levels than pseudochrome. It can sound very good indeed when used with the correct hardware, but that wasn't the way the industry went. Quite why BASF stuck with pure chrome until they stopped making cassettes altogether is anybody's guess. They were perfectly capable of making good quality industry compatible pseudochrome cassettes if they wanted to.
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Old 1st Dec 2022, 3:30 pm   #6
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Default Re: Pure Chrome tapes

Thanks @stevehertz

The seller is someone I have bought from before and he has a selection of different types and the pure chromes caught my eye. I get interested in shiny and slightly unusual things
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Old 1st Dec 2022, 3:36 pm   #7
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Default Re: Pure Chrome tapes

Quote:
Originally Posted by paulsherwin View Post
Pure chrome tape generally has lower sensitivity but lower noise levels than pseudochrome. It can sound very good indeed when used with the correct hardware, but that wasn't the way the industry went. Quite why BASF stuck with pure chrome until they stopped making cassettes altogether is anybody's guess. They were perfectly capable of making good quality industry compatible pseudochrome cassettes if they wanted to.
I think a lot of "premium" prerecorded cassettes were produced on BASF pure chrome tape. I remember some marketing material (including a cassette!) from the mid-80s extolling its virtues for duplication purposes. If that was their main market, it would explain why they stuck with the formulation - if the duplicators were set up to handle it in large quantities, they'd be reluctant to change.

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Old 1st Dec 2022, 3:43 pm   #8
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Default Re: Pure Chrome tapes

Real Chrome a-la BASF loses its remanence over time. Ironically, pseudo-chrome appears to have been invented so as the big Japanese firms didn't have to pay to license real chrome from BASF (who bought the rights from Dupont), but it keeps level pretty much to the dB, decades down the line.

See this link: https://audiochrome.blogspot.com/201...surements.html

NB - pre-recorded chrome tapes were typically designed to be played back with normal, i.e. 120uS EQ.

Taken from link:
Quote:
I have not seen a single chrome tape that is still close to its original performance.
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Old 1st Dec 2022, 11:20 pm   #9
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Default Re: Pure Chrome tapes

Interesting that apparently original old Chrome recordings have not suffered the same fate. They seem to play back fine. It seems the problem only affects new recordings on the old Chrome tapes, which I suspect would be generally very few in number.
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Old 2nd Dec 2022, 12:36 am   #10
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Default Re: Pure Chrome tapes

The handful of recordings on BASF Chrome tapes which I have from the mid-70's seem OK. I side-stepped the problems with the C90's (spaghetti) by sticking with C60's, which were OK just for compilation tapes.

As for why BASF stayed with Chrome, sometimes that kind of thing happens when a company has a "Golden Client" for the product who makes it viable?

B
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Old 2nd Dec 2022, 4:24 am   #11
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Default Re: Pure Chrome tapes

Probably BASF saw their 'Chromdioxid' as a unique selling point for marketing reasons. They could claim all sorts of things on the back of it, and gently suggest that pseudochrome was only for second-grade manufacturers who couldn't do the real thing. Gently enough to not be actionable, of course.

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Old 2nd Dec 2022, 11:00 am   #12
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Default Re: Pure Chrome tapes

That does seem a plausible explanation. The Chromdioxid branding on prerecorded cassettes does seem to have been a positive marketing point. In the high end blanks market the approach was completely delusional though - deck owners took care to select compatible tape stock, and nobody with any of the mass market brands (Akai, Aiwa, Sony, JVC, Hitachi etc. etc.) would have bought Chromdioxid. BASF must have known this, but had presumably developed some sort of corporate bunker mentality.

Ampex also made pure chrome cassettes for a while, though we didn't see a lot of them in the UK. I think Tandy sold them.
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Old 2nd Dec 2022, 11:29 am   #13
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Default Re: Pure Chrome tapes

If BASF could sell chrome stock to duplicators by the lorry-load, the domestic blank market wouldn't have mattered much. Mind you, I tried to play a promotional BASF chromdioxid pre-recorded cassette a while ago and the thing squealed and screeched like nobody's business...
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Old 2nd Dec 2022, 12:29 pm   #14
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Default Re: Pure Chrome tapes

The 'pure metal' tapes were a bit limited for the star ingredient in their manufacture tending to explode... during manufacture rather than use, at least.

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Old 2nd Dec 2022, 12:32 pm   #15
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Default Re: Pure Chrome tapes

My collection is 90% pseudo-chrome, but the BASF chromes that I do have (recorded by me on a 3-head machine in the '80s) are definitely lower in level than the other XL-II / SA recordings from the same period, by a handful of dB. I also found that one had completely seized.

Maybe I recorded them at a lower level...it's not a scientific explanation, but it would be a coincidence that all of them seem to be quieter than their super avilyn brethren.

NB - the biggest concern with tapes that have lost level over the years is Dolby level compatibility. If you suspect a tape has lost a few dB, then it makes sense to copy it to digital without Dolby, and apply it using a Dolby plug-in, whereby you can adjust the threshold.
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Old 2nd Dec 2022, 12:35 pm   #16
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Default Re: Pure Chrome tapes

By the time metal cassettes had been developed, pseudochrome technology had advanced so much that the quality improvement was only marginal. They were significantly more expensive, and there were some reliability issues, at least in the early days. They never really went mainstream, at least in the UK.
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Old 2nd Dec 2022, 12:41 pm   #17
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Default Re: Pure Chrome tapes

I suspect everyone who got a metal capable deck bought just one metal cassette. Symbolic, rather like getting a copy of "Brothers in arms" for your first CD player.

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Old 2nd Dec 2022, 1:17 pm   #18
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Default Re: Pure Chrome tapes

BASF invested millions in building the reactors to manufacture CrO2 themselves....no way they were going to write off that investment and go the cobalt doped route. Sony were the only Japanese manufacturer to try CrO2 cassettes and they did buy the stuff from DuPont before going the same route as Maxell and TDK.

I have used 1980s BASF Chrome Extra II with a Yamaha KX393 that has "auto tune" and it's wholly successful. The big advice is to keep the recording levels down to 0dB peak...unlike the psuedochromes which could handle considerably higher recording levels.

Where the genuine chromes fall down is Japanese made machines that simply have tape type selectors with no adjustment of the bias. Also some with fine adjustment of bias might not permit sufficient adjustment.

BASF did move to 70% CrO2, 30% doped cobalt some time in the 90s....and it has been said (by someone who should know) that by the end of the Emtec era they were "putting any old stuff" in the shells.
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Old 2nd Dec 2022, 3:47 pm   #19
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Default Re: Pure Chrome tapes

Re the earlier discussion on Chrome tapes having over time lost their ability to make good new recordings nowadays, this is a new one on me which Ive been trying to understand. If it's the case one would have thought the mechanism of degradation would have been discovered by now. I wonder if the alleged shifting bias and sensitivity requirements from the pseudochrome tapes, were the differences that were always there from new and some have simply recently discovered these inherent differences themselves.
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Old 2nd Dec 2022, 4:30 pm   #20
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Default Re: Pure Chrome tapes

I agree with Tim. Quite apart from the bias level, chrome tapes are less sensitive than pseudochrome, and recording at 0dB will result in playback several dB down if the deck isn't calibrated appropriately. This of course results in Dolby tracking errors, which make the recording sound even muddier than the incorrect bias alone.

There is a very detailed Wiki article on cassette tape types: https://en.wikipedia.org/wiki/Compac...d_formulations
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