I had the Prem 15 many years ago. It's a real nice unit. I ran a Koetsu RSP with .2mv, and it was not enough gain. I can't remember if it has an MM/MC inputs or MC only, but I think just MC. I would think a .5 or .6 mv cart would be pretty ideal. Something like a Shelter, or maybe one of the Ortofon's with a slightly higher output. An SUT would only make sense in to an MM input, but again, I didn't recall the 15 having one.