SUT vs. Phono preamp


On what basis is  the decision to chose  a SUT vs. a phonostage made?
boofer
Post removed 
@stereo5 that is good to know. I have a set of Cinemag 1254 transformers sitting here for a project. Now I can’t wait to hear them.
BillWojo
My phono stage is a Rega Aria, not exactly top of the line, but at $1500, no slouch either.

Ok, this is your phono stage

70 Ohm, 100 Ohm, 150 Ohm, 400 Ohm

63.5 db and 69.3 db



There are dip switch settings for all Rega MC cartridge models, but what about your MC cartridges, they are all Rega ?