radiomuseum.org
 

tefi: Tefifon - Moebius tape

Modérateurs:
Martin Renz Ernst Erb Vincent de Franco Martin Bösch Bernhard Nagel Otmar Jung Heribert Jung Eilert Menke 
 
Cliquez sur le bouton d'information bleu pour en apprendre plus sur cette page.
Forum » Radios, TV, Appareils techniques (Physique) etc. » MODÈLES PRÉSENTÉS » tefi: Tefifon - Moebius tape
           
Joe Sousa
Joe Sousa
Rédacteur
USA  Articles: 662
Schémas: 214
Images: 434
15.Aug.09 00:01

Remerciements: 7
Répondre  |  Vous n'êtes pas connecté, mais en mode visiteur   1

Hello Radiophiles.

I visited the personal web site of RM moderator Heribert Jung, and came across his Tefifon grooved tape player.

I was fascinated by this machine, and looked through RM to find out if the tape is single side or double sided. One of the photos under this model shows various tape sizes from 3minutes to 4hours.

The 3 minute tape looks like a short belt, perhaps 60cm in perimeter.

I would like to know if the tape is single or double sided.

One way to use both sides of the tape would be to have the tape ends glued to make a Moebius strip. This would allow continous play of "both" sides of the tape without having to reverse the tape.

A belt can be made into a Moebius strip by cuting and regluing with a twist on one of the cut ends, such that the tape ends up with a single continuous side and a single continous edge.

A Moebius tape configuration would place much greater flexibility requirements on the tape than the single sided version.

Regards,

-Joe

Rüdiger Walz
Rüdiger Walz
Conseiller
D  Articles: 696
Schémas: 151
Images: 224
15.Aug.09 20:19

Remerciements: 9
Répondre  |  Vous n'êtes pas connecté, mais en mode visiteur   2

Joe,

the 3 min tape has only a size of 20 cm. As you can see from the photo is is not twisted, so it can not be a Moebius tape. The ends of a Moebius tape are glued by twisting the ends of the tape. So you generate an endless groove. The short play tape was an attempt to be competitive to the single record. Young people bought the newest hits on singles and did not want to buy one hour or more music entertainment. You need a special adapter to play the single tape.

Tefi did not use Moebius tapes after WW2 because it could not be stored in the cassette. They used Moebius tapes in the pre-war Tefiphon ( play and record tapes) and Teficord (only play tapes)  (with "ph" ! Tefifon with "f" after the war). Here the tapes run free in the machine. See here and others.

Best regards

Rüdiger Walz

Cet article a été édité 15.Aug.09 20:21 par Rüdiger Walz .

Joe Sousa
Joe Sousa
Rédacteur
USA  Articles: 662
Schémas: 214
Images: 434
16.Aug.09 05:15

Remerciements: 9
Répondre  |  Vous n'êtes pas connecté, mais en mode visiteur   3

Rüdiger,

Thanks for the clarification. The Moebius method offers an obvious way to double play time, if the medium is thick enough to support opposite sets of grooves, and plyable enough to bend easily in opposite directions. Glad to hear that this was used where appropriate.

The Tefifon medium is completely new to me, so I would like to learn more about it.

I listened to the only Tefifon clip I could find at RM. It reproduced the sound of a  Tefifon M459/HS19 from the mid 50's.

It sounded like it might have come from a contemporary LP, played back on a ceramic cartridge. Which is to say it sounded quite good. The Tefifon sounded better than a contemporary 78rpm record. But I cannot be sure, given the short clip duration of only a few seconds.

Did the prewar Tefiphon and related machines sound better than the contemporary 78rpm records, in particular, with regard to surface noise, but also with respect to distortion and frequency response?

It would be interesting to hear the impressions from members about their comparison to Tefi tapes to contemporary LP, 78's, wire recorders, and magnetic tape players.

Regards,

-Joe

Rüdiger Walz
Rüdiger Walz
Conseiller
D  Articles: 696
Schémas: 151
Images: 224
16.Aug.09 12:53

Remerciements: 8
Répondre  |  Vous n'êtes pas connecté, mais en mode visiteur   4

Pre-war Tefi tapes are based on Celuloid. They used a standard magnetic pick up and a steel needle like a gramophone. So I would expect the sound in principle being on the same quality level like a 78 rpm record. I have to ask a colleague who has had a Teficord and some tapes. But you can imagine that the tapes have become brittle, so the quality today may not be the quality in 1939. The clear advantage at that time was the ability to play a 2 hour opera without any break.

But there is another problem. There is a study of an engineer of Tefi, Mr. Scherer from 1958. He pointed out following problems:

As long as Tefi was the first using PVC for their tapes, noise signal relatio and playing time was better than a 78 rpm shellac record. But as soon as the PVC microgroove record appeard on the market the situation changed. Before that Tefi also had the advantage to be able to perform a complete piece of music without any break. Now the LP has 20 min of playing time and it was easy to press singles as I explained before. Due to the cassettes Tefi only had a noise signal relation of 30 dB compared to a LP of 60 dB. The cassettes cause a rumbling noise. This is also the problem with the Tefi magnetic cassettes. They additionally need a gliding powder because the polyester they are made from did not glide as well as PVC. You can imagine that the gliding powder disturbes the magnetic recording by contaminating the magnetic head.

Tefi has had some high quality singers and musicians under contract but you always have to buy minimum one hour of music and it is difficult just to place the needle on the song you want to hear. So Tefi tried to introduce the single tape but without big success. The handling is much more complicated than a single record. Single records from different companies could be played on a standard record player, Tefi tapes only on Tefi players. There was no other distributor of Tefi-like tapes so you have been linked to the music programm of Tefi.

Also Tefi has its own distribution organisation. It was not sold via the normal Radio/TV shops which makes the penetration of the market more difficult. So Scherer predicted that Tefi will not be successful in the market any more and he was right. Tefi was closed down in 1965. Expecting that Scherer went in 1958 to Braun and constructed electric shavers in Frankfurt.

I had the opportunity to talk to him. He was a quite interesting man and after retirement he was active in local policy. "I dealt with technology my whole life and now I want to deal with people" was his statement.

Rüdiger Walz

 

Cet article a été édité 16.Aug.09 13:02 par Rüdiger Walz .

  
rmXorg