Dear Divo: I think that you are like many people ( like me ) that always are trying to find the best analog sound reproduction quality. The most important issue about a stepup-transformers is not the size of it or the quality sound of it, for the anolog music lover the most importantt issue is: NEVER USE A STEPUP TRANSFORMER, always use a preamp with a built-in high gain ( for low output moving coil cartridges ) phono stage. When you use a SUT the critical signal from your low output cartridges has to go trough additionals connectors and interconnect cables that degraded the signal, and not only this the signal degraded too because has to go trough severals meters of wire ( transformers ) inside the SUT. So, the best SUT is NO SUT. This is a fact and you can probe it: her the same signal trough a SUT and trough a preamp with a buil-in phono stage and you will hear the BIG difference.
Don't take my word for sure, do this test: hear it.
Regards and enjoy the music.
Raul.