Original URL: https://www.theregister.com/2013/09/02/compact_cassette_supremo_lou_ottens_talks_to_el_reg/

Compact Cassette supremo Lou Ottens talks to El Reg

'Successful products are created by normal people who just follow their intuition'

By Bob Dormon

Posted in Personal Tech, 2nd September 2013 09:04 GMT

Anniversary Q&A As a principal member of the R&D personnel at Philips, Lou Ottens has been behind some of the most enduring audio products in both the analogue and digital domains, from the Compact Cassette to the Compact Disc.

In this interview with The Register, Lou Ottens, now in his eighties, recalls the development of the Compact Cassette tech standard leading up to the product's launch 50 years ago. It was a device that, in its time, would change lifestyles, manufacturing industries and have mixed blessings for the music business too.

El Reg: "Devising the Compact Cassette would require people with knowledge of a variety of disciplines. What sort of team were you working with?"

Lou Ottens: "The group of engineers that I got to manage in the late 1950s and early 1960s consisted of mostly young people with experience in the design or manufacture of record-playing and tape-recording equipment in Eindhoven-based groups. It was a mixed group of Belgian and Dutch origin.

"We were lucky that we could always fall back on the knowledge available in the  laboratories and factories of the research centre in Eindhoven, 40 miles away. I am not sure how big the group was actually during, say 1960. Maybe in total 40 people, including those working on record players.”

Philips EL 3585 portable reel-to-reel tape recorder

The success of the Philips EL 3585 inspired the company to further explore portable recording
Image courtesy of Johan's Old Radios

El Reg: "Was there a particular product made by Philips that prompted the company to begin the project that would lead to the Compact Cassette?"

Lou Ottens: "Before the design of the Compact Cassette, we developed our first battery-driven reel-to-reel portable recorder, the EL 3585 came out in 1958, I believe, and was very successful. The total production was more than one million pieces. It made us confident that there would be a big market for a smaller, pocketable battery recorder."

El Reg: "Can you say more about some of the other products available that were influential from other manufacturers?"

Lou Ottens: "Somewhere during 1958 the US company RCA proposed in a worldwide campaign the introduction together with a standardisation proposal of their so called “quick loading cartridge” based on two flangeless hubs in a flat box. Flangeless hubs facilitate smaller dimensions because one reel diminishes as the other grows in diameter. It was based on the existing standard tape speed  3 ¾ IPS [inches per second] or 9,5cm/sec and reversible utilisation for 2 x 30 minutes in stereo.”

El Reg: "That sounds like a workable prospect, why didn’t it take off?"

Lou Ottens: “It was an intelligent solution, but with a few drawbacks. Quick rewinding and winding the tape could lead to jamming, and for us a very serious point: The power consumption due to the internal friction in the cartridge made it unsuitable for use in battery operated equipment.”

El Reg: "Were there many other viable alternatives available at the time?"

Lou Ottens: “Soon after the RCA proposal came a design from Dr Peter Goldmark of CBS, which consisted of one reel only. A piece of rigid leader tape that clicked between the outer rims of the flanges made it possible to be handled without de-reeling. It led to a rather complicated and not very reliable recorder, but it had an important innovation.

"Goldmark proposed a narrower tape of improved quality. He proposed a tapewidth of 0.15 inch (3,81 mm) and a tape speed of 1 7/8 IPS (4,75cm/sec). It had to be rewound after playing, which is very impractical."

El Reg: "Naturally, reliability and practicality are major factors to get a product accepted but presumably Philips had specific goals in mind to implement..."

Lou Ottens: “We, as a product development group, were aimed at the lower price range of the gramophone and recording market. New product proposals should therefore be cheap, small, have a low battery consumption, together with an appropriate reproduction quality.

"The Japanese competition on the market consisted of small, rim drive type reel-to-reel recorders of inferior reproduction quality and had a battery life of only a few hours. Our group was working on ideas for a successor of the EL 3585 and we were trying out different proposals for cartridges and tape sizes and tape speeds.”

Dux SA 6139 T clone of the Philips EL 3300

Doing the numbers: Sweden had its own variant of the EL 3585, the Dux SA 6139 T
Image courtesy of Johan's Old Radios

El Reg: "How did you go about 'trying out different proposals'?"

Lou Ottens: "When the RCA proposal came on our desk, and soon afterwards the CBS tape size, we made a working sample of a tape deck based on a shrunken sort of RCA cartridge with 20 minutes playing time and the CBS size of tape. It worked surprisingly well.

"The guys from the commercial product management were very happy with the proposal, but were in favour of 30 minutes – and they were right. Our first point of departure had been a good speech quality, but with the obvious potential suitability for music quality it was better to choose for a space that would equal the possibilities of a long play record which is a maximum of about 30 minutes per side."

Size matters

El Reg: Making everything smaller must have introduced some challenges initially. Were there any specific problems you recall with the prototypes?

Lou Ottens: “The EL 3585 had a capstan of 3mm diameter, but for a very small successor there was no room for the same size of flywheel. Therefore we chose  a 2mm capstan.

"For the test models we used 2mm stamping punches, which were beautifully straight and polished. But the music came out with a heavy flutter because of a microscopic triangularity inherent to the centreless grinding operation.”

El Reg: "The moving head array is a distinctive feature of Compact Cassette, how did this design come about?"

Lou Ottens: "The RCA cartridge had rather large recesses to accommodate room for the recording head and the erase head. That makes three holes where the tape is exposed when the cartridge is handled. We decided to minimize the tape exposure, so we didn’t want any big holes in the upper or lower surface of the cassette.

"As a result, the recording head, the erase head and the pressure roller had to move in. It is as simple as that. The patent people made it a patentable fact, stating that moving the heads into the cassette fixes the cassette into its position."

Compact Cassette meet RCA Sound Tape Cartridge

Compact Cassette and RCA cartridge compared
Source: Wikimedia/Creative Commons

El Reg: "Did this arrangement have any impact on head wear?"

Lou Ottens: "We didn’t care about headwear, nor was the tape travel subject to scientific analysis. Headwear was not very likely, because the tape tension during winding and rewinding is very small in comparison with those in reel-to-reel machines."

El Reg: "The positioning of the retracting heads needed to be precise, yet could be successfully mass-produced, how much of an engineering effort did this involve?"

Lou Ottens: "I am not aware of special problems with the head array, apart from the fact that the draughtsman Jan Schoenmakers was a highly talented man on the drawing board, with a past as a toolmaker. That makes for reliable designs."

El Reg: "The Compact Cassette is a very pocketable size. Had you decided upon maximum dimensions to work to?"

Lou Ottens: "Because our aim was to make a pocket recorder, it should fit into the side pocket of my tweed jacket. I made a wood block that fitted in my pocket. That does not mean that carrying the actual recorder in my jacket was very comfortable or advisable."

Philips EL 3300 portable cassette recorder kit

Made to measure: the pocketable EL 3300 – the first Compact Cassette recorder
Source: Philips Company Archives

El Reg: "Was the size of the cassette determined by the chosen spool size and tape thickness?"

Lou Ottens: "The size of the spool had nothing to do with the size of the recorder. We had the size of the cassette, the size of the 2.5in loudspeaker, the volume of five batteries (to have 7.5 volts), and the room for the electronics and two connectors [DIN for audio and remote]. All those things had to fit into the block size. Not easy, I remember."

El Reg:" The hub of the cassette could have varied in size considerably and would effectively change the 'gearing' of the transport mechanism. How was this decided?"

Lou Ottens: "Making a very small hub does not help much, because it does not gain much tape space. It only adds problems in the gearing and extra winding time. It is not too difficult to reach an optimum."

El Reg: "In my experience, the C-120 tape was frequently unreliable, with the take-up reel often slowing down and tape gathering by the capstan. Was the specification designed to take these heavier cassette reels with thinner tape or did they come later?"

Lou Ottens: "Originally, we planned only the C60 and the C90, if I remember well. At the time of the original design we did not know much of the future tapes and their behaviour. Philips was not an important or even knowledgeable tape manufacturer. BASF, 3M, Agfa, Sony, etc were the names."

El Reg: "With these companies working on tape formulations, did the arrival of CrO2 and metal tapes come as a surprise?"

Lou Ottens: "Metal and CrO2 came as welcome surprises, if I remember well. They were hectic times."

Cassette tape

Not 1/8in after all, but wider

El Reg: "Cassette tape is not 1/8in (3.2mm or 0.125in) as most presume, but bigger 3/20in (3.81mm or 0.15in). Did this choice of width present any problems for mass production to accommodate the specification and cassette tape thickness?"

Lou Ottens: "The width was originated by CBS, as 0.15in and we thought it wise to take over something that had been supplied to a big name as CBS [manufactured by 3M]. Actually, we had some initial jamming problems with the cassettes, which we at first had blamed on static charging. But it might also have had some connection with fraying due to difficulties in the cutting wheels that were not adjusted optimally, or ground securely, because later on the difficulties disappeared."

Setting standards

El Reg: "Can you explain the technicalities behind the sprung metal strip holding the felt pressure pad and the metal plate behind it in the cassette?"

Lou Ottens: "The pressure should be very light, because the forces inside the tape transport mechanism are kept as low as possible and any disturbance originating from a different pressure on the the tape can cause speed irregularities. The phosphor-bronze spring which carries the felt pad had been chosen to avoid eventual magnetism of a steel spring in the direct neighbourhood of the recording head. The mu-metal screen serves as a shield against interference that might be induced in the head during playback."

Cassette tape exposed

There's a lot more thought gone into this than just two spools

El Reg: "Did Philips have a frequency response in mind for the Compact Cassette or was it a case of experimentation to see what was the best you could get out of it?"

Lou Ottens: "At the time of the concept (somewhere around 1960 ) we were not thinking about hi-fi or something similar. A cheap, portable proposal which, hopefully, would find a willing market.

"As far as I remember, with this little machine, we were happy with 80Hz~5kHz [frequency response], which was in balance with the loudspeaker, the simple electronics and final stage and the existing tape performance. It would gradually improve, because the tape suppliers were in full swing."

El Reg: "Establishing bias and equalisation curves looks like it was a major R&D effort as these factors were to become standardised. Were other options explored, such as a new tape speed to deliver even better results?"

Lou Ottens: "As long as there was no technical revolution at stake, international standardisation was a holy cow with Philips, and rightly so. Tape speeds were standardised from 15 , 7.5 ips, 3 ¾ IPS , 1 7/8 IPS. No reason for us to choose something out of that range."

El Reg: "Had their been any significant technological advances that Philips was using that made the Compact Cassette recorder possible?"

Lou Ottens: "Yes. In the component division of Philips there was a considerable activity going for the miniaturisation of electronic components. The components, like electrolytic capacitors, ceramic capacitors, resistors, transistors (ICs were not yet a reality),     switches, potentiometers and connectors were made fit for direct mounting on a printed circuit board. Their height was standardised to a maximum of 10mm and we anticipated using them in time for when the parts became available."

Fisher Compact Cassette recorder with Dolby B from 1970

Fisher Compact Cassette recorder with Dolby B from July 1970

El Reg: "How did you feel about Dolby B being widely used on Musicassettes? It seems people didn’t remember to use Dolby B or even have it and so they were listening to bright, compressed audio which could be noisy too. Were you concerned or was using Dolby (at least, in theory) a welcome addition?"

Lou Ottens: "We didn’t like it at all. It complicated our products and it destroyed the international standard we had established with the competition. I was of the opinion that the rapid improvement of the tape performance by the international tape manufacturers would make the Dolby system obsolete, apart from the professional field, where the genius Dolby was normally active.

"I was afraid that it would cause a lot of confusion in the market. And I think I was right. But being right is not always good enough. Ray Dolby came to visit me and I gave my arguments, but he went on. Lesson: you cannot stop progress..."

El Reg: "Were you consulted on the development of the Digital Compact Cassette – DCC?"

Lou Ottens: "No, I was not consulted."

El Reg: "What are your views on the DCC format?"

Lou Ottens: "I am only slightly aware of the exact specification, so I will refrain from an opinion."

Philips EL 3300 portable cassette recorder launch in Berlin

The Compact Cassette launch at IFA in August 1963
Source: Philips Company Archives

El Reg: "Regarding the introduction of the Compact Cassette and the widespread adoption that would follow, what was the biggest problem that was overcome and what was the biggest surprise?"

Lou Ottens: "The biggest problem was to realise the timely introduction for the Berlin exposition in August 1963. The biggest surprise was the world wide revolution it caused in the individual availability of music. But that surprise came into being only very gradually, which is not normal for a surprise."

El Reg: "If you could have changed something about the Compact Cassette before its final release, what would it have been?"

Lou Ottens: "Nothing."

El Reg: "Is there anything else you would like to say about this landmark project?"

Lou Ottens: "I have tried to give answers that make it clear that successful products are created by normal people who just follow their intuition, work hard, make mistakes and work together as a bunch of friends. A number of the key personnel that played an important role have passed away since those days. I remember them with respect and friendship." ®