(1974) QDCS - Another Quad (Matrix?) System for Vinyl Records

[kfbkfb]

https://www.worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1974-01.pdf#page=30
https://www.worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1974-02.pdf#page=42
https://www.worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1974-03.pdf#page=50

I have the 1974-01 and 1974-03 issues of Audio, just skimming these articles, it looks like this is a matrix system for use on vinyl records only (although it's called a discrete system).

Anyone know more about this QDCS quad system?


Kirk Bayne