Dear David: Ok trying to help around : that 3012 tonearm is a little " alive " on upper mids/high frequencies, the Universe is a little on the bright side and not so good on the low bass ( against other top cartridges like your XV-1 ), so the contrast between both frequency extremes along the 3012 performance could cause what you are hearing. I can't remember if your SME model has a removable headshell but if it has then you can try the Universe with different headshells, this could help. By-passing the SUT could help too but this is a way different " history " and can't help you with out a phono stage change.
Regards and enjoy the music.
Raul.
Regards and enjoy the music.
Raul.