was it pre-amp and step up? if so which pre-amp?
It’s an interesting question, probably the SUT was connected to those big oldschool receivers (MM input), there are many of them.
I’m not expert in vintage phono stages, but something like Pioneer Exclussive system was very expensive in the 80’s, looks cute and still popular. The headamp for MC in "Z system" looks like this. Preamp with MM input is C-Z1. And the power amps (monoblocks) from this series is here. Kind of a cute little system for a very high price @parrotbee
I think in the USA at that time all those SUTs were connected to big and expensive Levinson and Krell preamps.
If you will look at the FR catalof from the 80's you will see only this stuff.