| 1971 - DUAL purchases P+E (Perpetuum-Ebner) a competitor. |
| 1972 - DUAL develops the first European Direct Drive Turntable, |
| the DUAL 701. Simultaneous damping of the tonearm |
| resonance from the spring suspension by using a elastic |
| connection. The solution was a two part anti-resonator |
| which is adjusted to a specific frequency. Together they |
| produce a mass to balance the tonearm system. |
| 1973 - The official introduction of Quadraphonic sound during the |
| electronic trade show in Berlin, Germany. |
| DUAL introduces a complete line of Quadraphonic equipment. |
| 1974 - DUAL completes the development of the first DUAL cassette |
| player, the model C-901 and begins production of this unit. |
| The technical features are: |
| Auto-Reverse |
| Self Degaussing |
| Automatic Adjustment of the Double Gap Erase Heads |
| Horizontal and Vertical Operation |
| Direct Function Switching |
| Dolby B Noise Reduction |
| 1975 - The first belt drive high-fidelity automatic turntable with the Vario-Belt |
| drive system is introduced. |
| An eight pole motor capable of 78 RPM is also introduced. |
| 1977 - The first hi-fi cassette recorder with a front-load system, the DUAL |
| C-819 is introduced. It also had a fader control and could use all |
| three tape types, photoelectric controls. Facilities for mixing from |
| a microphone and other sources were built in. |