About metal tape...

Discussion in 'Tape' started by Waterland, Jan 31, 2010.

  1. perryinva

    perryinva IS it vintage????

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    Type III was supposed to be a big improvement over the original Type II, pure chrome, but when most Chromes morphed into cobolt doped ones, with only BASF still making pure Chrome, the differences became pretty minor. When Type IV was intoduced, Type III died a quick and painless death. There was just no place for it, performance, or price, wise, and so little was made, that most all later decks, never even had settings for it..
     

     

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  2. Wilhem

    Wilhem Active Member

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    Type IV - metal pigment (MP) [or metal evaporated (ME) tape whose extremely thin coating rendered it poor for analogue audio recording]. TDK made the official IEC reference tape. The pigment is such a small crystal that it can oxidize extremely quickly, enough to cause spontaneous combustion or explosions at any point in the milling/coating operation unless extreme precautions are taken, such as submersion in alcohol and a nitrogen-based environment. The particles were passivated with molecules of oxygen around the metal crystal to stabilize them because early metal tapes oxidized and lost magnetic properties. There were other experiments to modify the crystals with other metallic alloys either to enhance magnetic properties or to stabilize the crystals. Metal tapes are relatively environmentally stable with the lowest amount of print-through. They generally have the highest MOL and SOL values, but also the highest noise, so in practice they exceed Type II tapes only in low print and better high frequency dynamic range. Headwear is no different from that of any other magnetic pigment.

    Type III -ferric-chrome tapes. Sony made the IEC reference tape. Thicker coatings increased MOL, and the "underbiased" thin layer of chromium dioxide brought low noise. However, the disparity in bias points between the two layers meant a sagging mid-frequency sensitivity that had to be compensated by boosting record EQ to such a degree that SOL values were very poor. (This was common to double-coated tapes but far less pronounced when the optimum bias points were closer, as in BASF Superchrome tapes and TDK SA-X.) Type III tapes were never very popular and disappeared with the arrive of Type IV formulations. Headwear was the same as that for pure chrome tapes: lowest of all tapes for soft heads; higher initial wear on hard heads until the granular ferrite surface was polished, then very low with little to no gap erosion over the life of the head (except for some Sendust heads were chemical, not mechanical, erosion was observed similar to that induced by some ferric-cobalt formulations.)

    Type II - chromium dioxide or ferric-cobalt pigment. BASF made all Type II reference tapes, despite what TDK claimed in its misleading advertising. These tapes used either DuPont's invention of chromium dioxide (manufactured only by DuPont of BASF because of the enormous expense in heat/pressure reactors required to form the particle) or ferric oxides enhanced by the addition of magnetic cobalt to the crystal structure. Chrome was the first Type II tape, but Sony's exclusive distribution deal with DuPont forced other Japanese tape manufacturers to find an alternative in ferric-cobalt (an Agfa-Gevaert invention that they were never able to stabilize properly until the Japanese figured how to do it.) Chrome had the lowest noise because of its perfect particle size and near perfect uniformity that allowed easy distribution in dispersions and excellent alignment under orientation magnets in coaters, but the first chromes also broke in milling and were susceptible to high print-through. Ferric-cobalts allowed higher packing densities that increased tape sensitivity at the lower frequencies--a compatibility point that the Japanese used as a "quality" issue against chrome tapes--and allowed higher MOL values. The tapes, however, suffered from higher noise levels, which actually increased over time as delta noise, and from magnetostrictive effects that reduced high frequency signals under pressure from the capstan/pinch roller combination. Chrome suffered from neither and actually had its noise level decrease over time--along with output--so the dynamic range stayed the same while Dolby noise reduction tracking was compromised a bit--with a slight loss in accuracy but a pleasant increase in treble response. BASF redesigned its milling operations to reduce print-through to levels equal to or better than ferric-cobalt tapes and improved MOL and SOL values with new particles and finally, the introduction of ferric-cobalt oxides with chrome for the "Chrome Extra" formulations. The same improvements were made to the double-coated Superchromes and Chrome Maxima tapes. TDK, frustrated by chrome's claims to be the "world's quietest tape," introduced double-coated SA-X with a very fine ferric-cobalt particle coated on top of the standard SA formulation. This lowered noise levels about a decibel or so below that of pure chrome tapes (before delta noise set it) but brought the curse of increased print-through due to the presence of para-magnetic particles among the finely milled top layer particles. All producers of ferric-cobalt tapes made improvements to formulations that slowly increased output levels with few compromises to dynamic range. BASF itself introduced a ferric-cobalt tape in a heat-resistant housing for car stereo use because chrome's low Curie point meant that signals could be lost if the tape were subjected to high levels of heat. (This worked to chrome's advantage when used in highs-speed TMD thermal magnetic video duplication.) Barium ferrite was an alternative pigment considered for audio but seldom used except for some video applications. Despite the nasty headwear scare used to dissuade people from using chrome tape, there is little difference in the amount of wear induced by any Type II tape that is properly calendered and finished. (All lubricant, emulsifiers, static reducers, and fungicides are in the magnetic dispersion. They are not added later in the manufacturing process.) There were some Type II metal tapes in the market to offer metal recording for older tape decks without Type IV settings, but the lower MOL and SOL values along with the very high noise levels and inability to be erased eventually killed these interlopers. The best ferric-cobalts and chromes easily outperformed these metal pigment products. Chrome tapes had their greatest day in audio duplication because BASF encouraged duplicators to use a playback EQ of 120 microseconds and back off the record pre-emphasis to improve SOL values by almost 5 decibels. (The 70-microsecond EQ setting came about when no one expected Dolby NR to become standard. Had the engineers known Dolby would be so successful, they would have left playback EQ the same for Type II tapes as for Type I. Chrome/Dolby NR/70 microseconds were all introduced at the same time to reduce tape hiss--but any two of the three options would have been sufficient. All 3 at the same time was overkill.)

    Type I - ferric oxide, cobalt-modified ferric oxide. BASF made the official reference tape. These are the first and most common tapes. The range of quality levels is greatest in this class because the oxides can vary so much and because reject computer tape designed for digital signals, not audio, sometimes made its way into cheaper brands. Some of the best Type I tapes could offer low frequency signal-to-noise ratios that matched or slightly exceeded Type II and IV tapes, but their high frequency performance was never as good because of the lower coercivity of the oxides. These tapes, with their less sophisticated particles, tend to be the most environmentally stable over time as long as the binder formulations are stable. (Polyurethane binder breakdown is a plague among ferric reel-to-reel formulations from Ampex and Agfa; acid ooze is more common in cassette binder failures.) Headwear varies among tapes only because of different levels of quality in finishing the tapes: the better quality of tapes have no problem. Some ferric-cobalt Type I tapes have shown some chemical erosion on some Sendust heads, but one could argue whether it is the fault of the tape or the head design. In general, headwear is not a problem. (As a topic, headwear is a fascinating topic, rife with misinformation and rumors.)
     
  3. aabottom

    aabottom Swing

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    Wilhem-

    Not bad for post #2. Welcome to AK.
     
  4. BlazeES

    BlazeES Active Member

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    Not entirely accurate. FeCr tapes had a useful production run of nearly 10 years, so I hardly call that insignificant. Scotch Master III's actually sold in large abundance in the middle to late seventies. The four predominate brand players in the FeCr cassette market were Scotch, BASF (AFGA) and Sony. Also, to say that FeCr died a "quick" death once Metal tapes were introduced is a bit of a misnomer; Metal tape was highly suspect in terms of reliability and headwear concerns, for several years. Perhaps it's more accurate to state that FeCr phased out in accelerated fashion once Type IV's began to take a firmer hold in the consumer market round about 1983/1984 - when head designs started to drastically improve. One last thing worth pointing out is that cobalt doping was employed long before FeCr's ceased to be produced and really had nothing to do with the demise of the FeCr format; FeCr was always intended to be the bridge platform between Type II and Type IV and unfortunately suffered from delamination issues as well as equalization/compatibility problems. That said, FeCr Type III's experienced a longer useful run than pure chrome ever did - in the consumer space. Lastly, what the FeCr formulation brought to the table was a significant blend of Type I low frequency response coupled with the sharp response of Type II's - FeCr was more akin to what good metals ultimately offered in terms of extended low frequency response - something Type II's never really quite achieved, so characterizing the differences as being "pretty minor" between Type II & Type III is another misnomer.
     
    Last edited: Mar 30, 2011
  5. Wilhem

    Wilhem Active Member

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    "FeCr was always intended to be the bridge platform between Type II and Type IV and unfortunately suffered from delamination issues as well as equalization/compatibility problems. That said, FeCr Type III's experienced a longer useful run than pure chrome ever did - in the consumer space. Lastly, what the FeCr formulation brought to the table was a significant blend of Type I low frequency response coupled with the sharp response of Type II's - FeCr was more akin to what good metals ultimately offered in terms of extended low frequency response."

    BASF never experienced delamination issues with FeCr because the base ferric layer was not cross-linked, for better adhesion to the PET film while the upper layer of chrome did use a cross-linked binder for lower rub-off. The same applied to double-coated chrome tapes. I don't know enough about other ferric-chrome tapes simply because their significant inherent limitations made them less interesting than advanced ferrics, chromes, and metal formulations. Whatever benefit in low frequency response they offered, it was simply due to thicker coatings that resulted in more magnetic material that increased MOL. Since the bias point was higher, that decreased LF distortion more, allowing even higher MOL values than those provided by a thicker coating. However, AH10 (SOL at 10 kHz) values were worse than ordinary ferric tapes because of coercivity mismatches between the two layers. A cobalt-doped ferric base layer would have been one solution, but BASF and TDK were already double-coating Type II tapes with the kinds of results they wanted. I'm not sure what you mean by "extended low frequency response." Extensions at the low end are a function of head geometry, not the dispersion.

    BASF and all other ferric-chrome suppliers dropped Type III tapes by 1982-83. BASF continued to coat pure chrome tape until 1996 when it sold the magnetics division to Kohap as "Emtec," and Emtec continued coating chrome until it failed in about 2003. Pure chrome tape was a large part of the European retail cassette market, and in the U.S. BASF pure chrome tape was in the fifth position in the Type II market until 1996 when the consumer division was killed off. In the music duplication market, pure chrome and the subsequent 80/20 chrome/cobalt "Chrome Extra" was 15-20% of all the top Billboard releases until cassettes faded away. (TDK tried to crack the duplication market in 1987, but pancakes of TDK SA were too dirty, too inconsistent, and too badly wound to replace BASF chrome tape.) So, if ferric-chrome died in 1983 and pure chrome lasted until about 2003, how is that considered a "longer useful run"?
     
  6. BlazeES

    BlazeES Active Member

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    Show us some real stats that "pure chrome" formulations lasted until 2003 in the compact cassette format. Not in the US they surely didn't. Can't speak for the R2R market but hybrid Type II's dominated from the late seventies onward. Can't speak for the European markets either. In any event, a nearly 10 year jaunt in the consumer space for FeCr is nothing to shake a stick at, that was my point. Simply put, pure chrome formulations were few and far between during the golden age of the compact cassette - regardless of specific longevity/availability in a particular market segment. Type II hybrids or treated formulas are quite different from the rash of "pure chromes" that were commercially available in the compact cassette space.
     
    Last edited: Oct 11, 2011

     

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  7. Wilhem

    Wilhem Active Member

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    The first pure chromium dioxide tapes appeared in 1969. BASF marketed them from 1970 to 1996 when they sold out to Kohap/Emtec and ended the retail consumer business. However, Emtec pure chrome tapes continued to be sold into the professional market until Emtec collapsed in 2003. That is 33 years, which is longer than 10 years. BASF had only a small market share of the Type II retail market when compared to Type II ferric-cobalt tapes, but even at its worst, sales of Professional II pure chrome tape was 50% of all the sales of BASF, Sony, and 3M ferric-chrome tapes combined in any single year. DuPont's pure chrome tape was extremely small, but its sales would add to Pro II's numbers.

    In the music business, pure chrome tape began in the U.S. in October 1982 with Supertramp's "...Famous Last Words." This was the last year for ferric-chrome tapes. Sales of pure chrome pancakes really took off with the Police's "Synchronicity" and never looked back. Mobile Fidelity's releases on cassette were all BASF pure chrome tape. In some months in the late 1980's and early 1990's nearly 25-30% of all music cassettes sold in the U.S. were on BASF pure chrome tape. Emtec continued selling pancakes of chrome/cobalt until 2003. That would indicate that chromium dioxide cassettes, not ferric-chrome, had a longer useful run.
     
  8. BlazeES

    BlazeES Active Member

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    So we agree then, we aren't talking about pure chrome in the "blank" stock consumer market space. You're comparing FeCr blank to the commerical recording industry. Apple to oranges my friend and not germaine to the topic of consumer space blank stock. To be quite honest, no one was proposing that FeCr had a longer mfg life than pure chromium dioxide in total, much less having been used to any large degree in the commerical, high volume duplication market. Pure chrome was a cheap way to for mfg's to churn out the garbage piles of (most) pre-recorded tapes. When it comes to in-home recording, pure chrome was thin going. In any event, FeCr had more than just a meager life-span in the consumer blank space -that's all I'm saying.

    The compact cassette format, elcaset and even some R2R market share is significant.

    Would still love to see some actual & available citings/statistics overall though...
     
    Last edited: Jun 3, 2011
  9. Wilhem

    Wilhem Active Member

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    "That said, FeCr Type III's experienced a longer useful run than pure chrome ever did - in the consumer space."

    Apples? Oranges? I thought the metric you originally introduced was years. 1969-1996 is 27 years for pure chromium dioxide in the United States market. 1974-1982 is 8 years. My mistake. I thought 27 was longer than 8. BASF Chrome Dioxid, Studio II, Professional II, Chrome Super II, Chrome Extra, and Chrome Maxima never sold as well as Type II ferric-cobalts in the U.S. market. The only other pure chrome tapes were Advent Chrome, DuPont Crolyn, and attempts by Philips and Agfa to get into the retail market. (Europe was a much bigger market for pure chrome tape stock in retail blank cassettes.) But sales of pure chromium tape stock from BASF over a period of 27 years was far greater than all of the ferric-chrome tapes sold by BASF, 3M, or Sony. MMIS or ITA might have some old statistics I could dig up if I get the chance.

    Pure chrome stock was not a "cheap way" at all for the music industry at all. They paid a premium for chrome and objected at the higher cost. CBS/Sony tried to talk Barbra Streisand out of chrome for her "Broadway" album, but she insisted on using the best available tape and went platinum with chrome. As I mentioned before, TDK attempted to enter the market by getting a line devoted to their SA tape at WEA's Specialty plant in Wilkes-Barre/Scranton. WEA tried for six months to improve the tape, but WEA finally threw it out for running dirty and for bad winds. TDK tape was very inconsistent, but that may have been because their coating facilities were making running changes to try to match BASF stock. When a single pancake is 4 miles long and you run them 24 hours a day, every day of the week, you quickly get a good idea of tape consistency and quality. Consumers preferred TDK SA. Engineers and technicians preferred BASF pure chrome.
     
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  10. BlazeES

    BlazeES Active Member

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    Most if not all of the BASF related "Chrome" branded tapes you listed were in fact NOT pure-chrome but actually formulary hybrids like most tapes of the 80's and 90's. And you know this. Don't let the marketeer angle cloud your judgement. Produce some dox and we'll continue the debate. Pure chrome in the blank tape consumer space was commercial fail and it's widely known. I think we're done.

    Pre-recorded offerings are an entirely different subject and quite frankly, most audiophiles steered clear of that nonsense - regardless of what particular entertainers may have demanded. And that MoFi market sliver was luxury and far from mainstream.
    Interesting read though...

    Let's start digging for technical citations and start from there...
     
    Last edited: Mar 31, 2011
  11. Wilhem

    Wilhem Active Member

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    DIN Type II Reference Tape C 401 R BASF 100% pure chrome
    IEC Type II Reference Tape S 4592A BASF 100% pure chrome
    IEC Type II Reference Tape U 564 W (replaced S 4592 A in October, 1987, in the IEC meeting in Prague)

    Magnetic Media Information Services, Volume XIII, No. 5 (August 20, 1993) discusses the technical work of Dr. Manfred Ohlinger, BASF's chief of pigment development. Dr. Ohlinger discussed work on CK60/XH, a chrome pigment with a coercivity beyond 1000 oersteds. He had already produce CK/75/230X with a value of 900 oe. and CK57/200X with a value of 670 oe. BASF was in full development of advanced pure chrome pigments for new 3480 cartridges and other media.

    BASF had been producing pure chromium dioxide pigments in a huge reactor in Ludwigshaven, Germany, since the late 1960s. In 1995 the oxide lineup included:
    CK 40-14 for audio tape
    CN 43-11 for high performance, single-coat audio tapes
    CK 37-11 for the lower coating of high performance chrome audio tapes. This pigment was designed for non-cross-linked binders.
    CK 48-21 was for the upper layer in cross-linked dispersions. These oxides were used in Chrome Super and Chrome Maxima tapes. The tapes were identical and differed only in the housing and the tighter specs for Chrome Maxima. Most Chrome Super performed exactly the same as Chrome Maxima.

    CK 50-21 was pure chrome used in VHS, S-VHS, TMD, and DCC formulations. (BASF made the only DCC tape. It was the tape in TDK and every other DCC cassette made.)

    There were CC variations of these pigments. They differed in that oxygen molecules were attached to the crystal surface to prevent degradation to hexavalent chrome in the presence of water.

    BASF used 100% pure chrome formulations for its EE reel-to-reel tape and for Loop Bin Master 920 and 921 used in the duplication industry before digital bins arrived. The only "hybrid" chrome/cobalt audio formulations appeared with the introduction in 1993/94 of "Chrome Plus" duplicator tape that had a small percentage of cobalt-ferric pigment added to raise AT315/MOL315. Its AT315 was 2-3 dB better than competing chrome tapes. Chrome Plus was also used in Chrome Extra audio cassettes from that point forward.

    In 1992 world-wide production of magnetic powder by weight was 11% for chromium dioxide, 55% for co-fe, 32% for standard ferric, and 2% for metal powder. This total includes all applications: audio, video, computer data.

    In 1994 BASF used a high-performance plastic that could withstand 95 degrees C. (203 degrees F.) without deformation. This plastic was used in the sonically welded Reference Maxima series. The tape was BASF ferric-cobalt because the heat resistance of the plastic would be wasted on a tape that had a much lower Curie point. (It was chrome's low Curie point that made it the only choice for thermal duplication--TMD--that was used for high-speed video tape duplication.) BASF kept Chrome Maxima and Chrome Super in the cassette lineup as 100% pure chromium dioxide tapes and the 85/15 Chrome Extra as its first and only hybrid chrome audio tape.

    As for "audiophile" opinions, I remember reading a discussion in The Absolute Sound condemning the process. It was obvious that the writer, an editor at the magazine, had little idea of magnetic recording. If you want an audiophile journalist's perspective on high-speed duplication, you would have to turn to John Borwick or Angus MacKenzie's work in British publications.
     
    Last edited: Mar 31, 2011

     

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  12. BlazeES

    BlazeES Active Member

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    Glad to see you digging through the inter-tubes and extracting the history of cassettes from such reputable sources such as "Vintage Cassette". Moreover, citing IEC Reference Standards speaks nothing to the actual formularies or recipes used in mass market production - those IEC specs are for performance based metrics and and reference "standards" provided by the unique companies chartered or granted the IEC spec authority for the declared reference standard - but the IEC specs do not in any way define or reveal the production formularies used for mass production. Those formularies are company IP. And citing pigments? OK. You got me. LOL

    Any idea where 'Magnetic Media Information Services, Volume XIII, No. 5' can be obtained?
     
  13. Wilhem

    Wilhem Active Member

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    None of that information comes from the Internet. They come from internal BASF documents describing slurry compositions and from R&D meeting notes.

    The point of IEC specs is that they were the target specifications we used for our production of magnetic media. When the reference was 100% pure chrome, as it was for two cases, it was not difficult to use 100% chrome formulations to meet the specs.

    A subscription to MMIS cost about $10,000 per year, but every tape/disk/hardware manufacturer subscribed because it was the best source of information about new developments in pigment, films, dispersions, processing, hardware, and marketing. The archived copies used to be found on their web site, but once Larry Lueck, the publisher, died, the site closed. I have a series of copies dating back to the mid 1970s when I started in chemical R&D and testing for BASF at their American coating plant. You might be able to find copies in chemical libraries devoted to analogue recording technology, but too many people today are quick to reject the old information.
     
  14. BlazeES

    BlazeES Active Member

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    I was referring to the Supertramp and Police references. Sorry, should have been a bit more specific about that.
     
  15. Wilhem

    Wilhem Active Member

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    I didn't have to look up any references to Supertramp or the Police, either. I met with both groups to present them with test copies and an explanation of why we wanted 120 microsecond EQ for chrome tape instead of the standard 70 microseconds. A&M wanted them to be prepared in case anyone asked about the change on their promotion tours.
     
  16. Sleep

    Sleep Well-Known Member

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    Brief contact with the terminals of a little 9v battery burns it up! I could see being inside an electronic device causing concern.

    I've only got a couple of NOS metal tapes, few enough that I'm saving them, but so tempting to try out!
     

     

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  17. lorne

    lorne Sonic Lizard

    BlazeES
    + that.

    When the local Sony repair center (here in Sendai Japan) told me that my favourite metal Sony tape had just ceased production, I went and bought what I think is years of supply of Type II. By the way, a Sony engineer told me that the technology used in the last emanations of their VHS tapes was trickling down to their tertiary Type II production. He had worked on this project. I am assuming that this brought their Type II tapes closer towards the performance of metal tapes — in some ways.
     
  18. melofelo

    melofelo Addicted Member

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    nice info wilhem...
    Always been a fan of Basf from their slick Chromdioxid II in the early 80's to the Chrome extra and chrome super maximas.

    If i remember correctly the chromdioxid II tape was probably the quietest of any chromes that i've used although it didn't like being pushed above 0db on peaks..
    A great tape for those allergic to dolby like myself :D:thmbsp:
     
  19. lorne

    lorne Sonic Lizard

    Allergic — yes ... good word to use in connection with tape. I don't care if it is Type I crud made in Sloboviastan at 4:48 on a Friday — I won't use Dolby. I'll just overlook the noise and take the signal straight up — stirred, not shaken!
     
  20. melofelo

    melofelo Addicted Member

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    a little stash of basf chromes..:D
     

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