Teldec

Design prototype of a player for the Telefunken TeD video disc

In the early 1970s Teldec was acting for Telefunken in the development of a disc manufacturing technology for Telefunken's "TeD" video disc player TD1005, released in 1975. The Television Electronic Disc (TeD) system was more or less a predecessor of the more successful optical Philips LaserDisc video system, as the TeD system employed the idea of using FM instead of AM for storing the video signal on a disc for the first time.

The TeD video-disc player used a piezo-electric pick-up cartridge with a diamond stylus, mechanically sampling the frequency-modulated, PAL-encoded audio-video signal from thousands of concentric grooves, vertically recorded into the surface of a very thin, flexible vinyl disc. The disc was freely rotating on a thin cushion of air between the disc and a fixed plate at 1500rpm (25 Hz), the disc being stabilized only by centrifugal force. The sampling frequency of the combined audio-video signal was about 2.7 MHz. Maximum video playing time was ten minutes on a 210 mm disc, amounting to about 15,000 concentric grooves on the disc, each storing two half-frame PAL-video-lines.

A technological spin-off from the short-lived TeD video system was Teldec's Direct Metal Mastering technology, called DMM, for the manufacturing of vinyl records: The cutting lathe engraves and impresses the audio signal (via Blumlein stereo cutting) in the copper-plated mother disk, instead of in the lacquer coating on an aluminium 'grandmother' disk. This bypasses the need to electroform a father disk, firstly, and allows better retention of the modulated signals in the groove due to the copper phase not possessing the strong elastic memory of the lacquer coating on traditional blank disks.

Teldec's label Das Alte Werk specialises in early music

A focus in the catalogue of the Teldec was the field of early music and historical performance practice, which were marketed from 1958 under its own sub-label Das Alte Werk. The first significant recordings were by Nikolaus Harnoncourt and his Concentus Musicus Wien, then later also with other orchestras, who became one of the main artists of the label. Teldec's largest project in this area was the prize-winning complete recording of Bach cantatas, which were recorded from 1970–1989 jointly by the Concentus Musicus Wien conducted by Nikolaus Harnoncourt and by the Leonhardt-Consort with Gustav Leonhardt. Teldec did not however achieve the distinction of completing the first set of these works, losing to the rival series by Hänssler Classic on conventional modern instruments by Helmuth Rilling. (This started later in 1975 but managed to meet Teldec's original 1985 Bach tercentary year deadline for completion).[1] Das Alte Werk also produced the first recordings of reconstructed versions of Monteverdi's operas L'Orfeo, Il ritorno d'Ulisse in patria and L'incoronazione di Poppea in a Zurich Opera cycle under Harnoncourt. In the 1990s Das Alte Werk recorded a few newer artists such as the ensembles Tragicomedia and Chanticleer, but effectively ceased new projects after Teldec's acquisition by Warner Classics.