Manitunc: "By the way, does anyone remember a system that used 3 ball bearings on the bottom in a triangle with one ball bearing in the arm sitting in the middle in a kind of unipivot arrangement that was much more stable than your usual pinpoint pivot?"
I believe you're talking about the Hadcock tonearm. Here's an excerpt from a review in 6moons:
"So, with a blast of trumpets, let's now unveil the £689 Hadcock 242SE. It looks like a conventional unipivot, except it's not. The needle point isn't so much a needle as an elongated cone tip. The cup isn't a cup at all because it holds four tiny brass balls to act as a bearing. So it's a compromise, really - a semi unipivot, its scale reduced to virtually act as a unipivot while producing the greater stability inherent in a dual-pivot design. Very clever, you say - but does it work? Let's find out."
Here's a picture.
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