Dutchaudioclassics had the opportunity to interview Hans Mons, a pioneering figure in the development of the Compact Disc. In this interview, Hans Mons delves into his role in the development of the ALP and his experience during the process. He also talks about his experience working with Sony and other companies during the development of the Compact Disc. It is an interesting read for anyone who wants to know more about the history of the Compact Disc and the people behind it.

Hans Mons

Hans Mons, born in 1945 in Amsterdam, completed the five-year HBS-b education in Amsterdam. After successfully completing this education, Mons studied at the TH electrical engineering in Eindhoven.

In spring 1970, Mons began working at Philips in the main industrial group RGT in the HiFi design group of the Radiolab. At that time, Philips had a wide range of possibilities and Mons had a great interest in the technical designs of amplifiers and other audio equipment. There, Mons worked on the amplifier part of the Philips 22RH720 Hifi/stereo radio amplifier combination. Mons also worked on the technical designs of the MFB speakers Philips 22AH532, Philips 22RH544, Philips 22RH545 and made a principle design for the 22RH541.

Hans Mons showing Pinkeltje Hans Mons, 68 years old, showing the Philips Pinkeltje development model at the Evoluon in 2013 (Source: anderetijden.nl)

In early 1974, the industrial group 'Audio' and the NatLab jointly began developing an optical audio disc with a diameter of 20 cm, the ALP (Audio Long Play). The goal was to surpass the sound quality of this disc that of the fragile vinyl LP. To achieve this goal, Lou Ottens, the technical director at Audio, formed a project group.

In November 1976, the ALP project group relocated from the Nat.Lab to the main Audio industry group at Strijp-S. Lou Ottens aimed to maintain control over the ALP development and have easy access. After the relocation to Strijp-S the ALP group consisted of Loek Boonstra, project leader, Toon van Alem, Jan van de Veerdonk, Cor Vos en Hans Mons.

Mons retired on 1 June 2005

Hans Mons 8 march 1979 introduction compact disc system Hans Mons at age 34, shown on the right, shows a compact disc to the press.

What part of the Compact Disc system did you research? What part were you responsible for?

During the ALP period, I was the only electronics engineer and primarily did research and design work for the encoding and decoding electronics. I worked with Lorend Vries from NatLab. In practice, I also did a lot of design work for the servo electronics.

What was the purpose of developing the compact disc/ALP?

More user convenience was one of the goals. From the compact cassette, we knew how important a small format was. For the CD, we had set the same goal, the sound carrier had to be compact. Furthermore, it had to be easier to handle than the LP and the sound quality had to be as good as possible.

Philips ALP player One of the first development models made, based on the agreements with Sony, with EFM modulation and the CIRC error correction system

After internal demonstrations to the Philips Audio management and demonstrations to the world press in March 1979, a delegation you were part of went to Japan. For what purpose did Philips go to Japan?

Soon after the internal demonstrations, Philips realized that it could not market the CD alone. They want to avoid situations like with video cassettes. It was important to have one global standard. After all, the guiding principle is that the CD should just do it anywhere.

Could you describe the process and details of the delegation's trip to Japan in March 1979 to find a partner for the Compact Disc system and the decision to work with Sony?

The Japan trips took place from 14th to 23rd March 1979. The delegation consisted of eight members: J.J.G.Ch. van Tilburg as director of the main audio industry group, L.F. Ottens as technical director, J.P. Sinjou as head of the CD laboratory and me as the specialist responsible for electronics. We had to complete a packed program with a total of nine demonstrations on six demonstration days. The transport of all the equipment proved to be an unusual undertaking.

Hans Mons, developer Compact Disc Hans Mons, at the left, standing at one of the development models

In order not to lose sight of the prototypes (two identical "cubic-metre" electronics and four Pinkeltje drives), all the technology travelled to Tokyo in the first-class passenger cabin alongside the Philips delegation. The decision to work with Sony came at the end of the trip to Japan. Sony let van Tilburg know that they wanted to work together. Matsushita (Panasonic) let us know during the trip that they did not want to work together. Except for questions from Japanese developers after the demo, there were no technical talks with Sony or other Japanese companies during that trip.

What was your role after the negotiations with Sony were completed?

During the negotiations with Sony, I was responsible for what we called Subcoding on the Philips side, which was the part of the coding that stored information like track numbers and timecode. The Japanese engineers could hardly believe that we had managed to fit the technology into such a small box. We managed to keep the technical problems we were still struggling with under the table, literally and figuratively.

A nice anecdote concerns the dimensions of the disc. The original CD had a diameter of 11.5 cm, representing a playing time of 60 minutes. However, one of Sony's executives demanded that his favourite performance of Beethoven's Ninth Symphony should fit on it. This one lasts 74 minutes. He stood firm, and we thought: what the hell? Most of all, we wanted to keep going. So the CD's diameter was increased to 12 centimetres.

Did the development of the Compact Disc system continue after the CD player was commercially introduced?

Because the Japanese competing systems also had the ability to store text and graphics, Philips and Sony wanted to be able to offer that as well. I began working on that during the development of the CD100 and also went to Japan frequently for that. Afterwards, I continued to handle the system negotiations with Sony for CD-ROM. I also worked on CD-ROM, CD-PROM, CD-R, pro-audio CD players, CD-Video, CD-I; file systems for CD-R, DVD, and Blue Ray Disc at Philips.

Hans Mons Philips compact disc On March 8, 1979, the introduction of the Philips Compact Disc System was held in a hall filled with journalists. On the right side is Hans Mons.

How did the record companies react to the arrival of the new compact disc format?

The record companies' behaviour was pathetic. We were barely scolded. They had no desire to invest in the CD, while the business of the LP and cassette, and in the US the 8-track, was doing well. They didn't see the importance. If Philips wanted to market CDs so badly, they should invest themselves. In the end, we managed to convince the record companies. The rest is history.

What aspect of the Compact Disc system that you worked on are you the most proud of and what stands out the most to you when you look back on the period when the CD player was developed?

Starting in 1979, CD-related technical cooperation and technical negotiations with mainly Japanese and also American companies were the common thread for me. It was always very interesting and special.

What is the origin of the name "Pinkeltje" for the ALP prototype player?

Just before Christmas in 1978, the ALP player was finished. It was deliberately kept very small with a view to later demonstrations. Earlier analogue and digital test units were nicknames "Johanna" and "Kidogo".

Joop Sinjou (head of the CD lab) showed it to the community of the CD Lab. He said “this here is our small boy, shall we give him a name?” At the time, I read the children's book Pinkeltje to my children, So I suggested the name Pinkeltje, to emphasise the prototype's compact dimensions. Pinkeltje was a dwarf and the central figure in a Dutch fairy tale written by D. Laan.

Pinkeltje was the last ALP player

Philips Pinkeltje One of the Pinkeltje development models Philips Pinkeltje drive A photo of the inside of the ALP player Pinkeltje Philips Pinkeltje cubic meter electronics Pinkeltje one cubic meter electronics ALP players Philips Historisch Producten museum in Eindhovern Two prototypes on display at the Philips Historische Producten museum in Eindhoven. On the right is a "Pinkeltje" ALP development model, and on the left is a later development model.

What CD players did you own?

I have owned multiple CD players throughout the years, including a Philips CD100, several CD-ROM players, and a few SACD players. Among all of them, my favorite is the Philips CD100 as it was the first commercial CD player.

Are you still active for Philips or in the field of the Compact Disc system or related technologies?

No, that all stopped upon my retirement.

Thank you.

You're welcome.

Hans Mons, one of the developers who was part of the team behind the Philips Compact Disc System.