Hi Rose!
I´ve had Moon W-3 driving my Mini-Utopias with good results. The amp is powerfull with plenty of distinct bas and nice midrange but may be a little lean in upper treble.
Although I´m not 100% shure wether leaness come from amp or speaker. Sound is very detailed even at small levels and runs in classA first 5 watts.
I now use Jadis (second hand) tube amp and it helped take away some of the leaness. It was a recommendation from an audio retailer. Cables can also make a difference.
Utopia are of old version without Berrylium elements for treble, don´t know if Minis ever where produced with Berrylium. I kept Minis for their exellent: monitoring/soundstage and ability to play loud without affecting sound quality. I also have SubUtopia (active
200 watts)