Studer A80 history

1970    "A new generation of the series A80 professional studio tape recorders is introduced in the Spring of this year." *
1971    "A new studio tape recorder, the model A80/R "Broadcasting Version" complements the A80 series. *
1972    "The versatile concept of the professional studio recorder A80 permits its conversion into a quadraphonic model, which is called A80RT-Quadra." *
1975    Studer Canada launched the A80/VU-16-2" at WABE '75 Hotel Vancouver. Bruno Hochstrasser loaned it to Little Mountain Sound (LMS) Vancouver where I worked
1975    Studer Canada A80/VU price list shows "Mk I" 8T-1" and 16T-2" transportable versions
1977    LMS installed the first Studer A80/VU-24-2" Mk II in Western Canada; I worked on this project
1980s   A80 Mk III and Mk IV multi-tracks with faster punch-in with a single erase head closer to record head, transformerless I/O, Dolby HX (Mk IV), etc
1989    A80 End of Production **
1998    A80 End of Maintenance Support by audiohouse.ch GmbH **

I'm unable to find the changeover date from A80/VU Mk I to Mk II, estimate early to mid 1970s as technology and designs improved. Others in this forum might provide more details. I believe serial numbers starting from "10,000" were assigned to Mk II machines to distinguish them from Mk I. A80 VU Mark I has centre-tapped repro heads, black frame VU meters, no removable EQ cards for Rec/Sync/Repro cards as Mk II, etc.

Re: A80 sales volume: "The fundamental corporate policy of Studer is to manufacture and market only well-engineered products with a long service life. With over 10,000 sales, the series A80 proves that Studer customers appreciate this policy." ***