JVC and RCA CD-4 Quad mastering

[threetotwoscully]

Does anyone in this forum have first-hand knowledge, or perhaps you own some of the old equipment, about the equipment and methods used by JVC, RCA and perhaps others to master CD-4 discrete-Quad records back in the 70s? Audio press and JAES articles from the day indicate cutting was done at 1/3 speed to successfully cut the high-frequency FM information for the rear channels. I have some of these records and it's surprising how well they work, also that the FM carrier can survive a pretty rough surface.

Anyway, any and all first-hand knowledge much appreciated.

[Phinster]

I don't know much I'm afraid...saw one being cut at RCA NY around 1980...the cutter head was an Ortofon ,red in color...half speed I was told...that's all I remember haha!