Seconding Grinnell, the Reference 3a De Capo's are a wonderful option. They love tubes... I'm running mine on little Manley Mahi monoblocks; I have a similar sized room to yours. I run the Mahi's in triode mode (20 w/ch) and I can't run them any louder than 9 o'clock on the volume knob. Enormous soundstage, stellar imaging and tonality. Killer on female vocals!
If you can't afford the De Capo's, have a look at their little brother, the Dulcet. I've owned both and they're both great.
If you can't afford the De Capo's, have a look at their little brother, the Dulcet. I've owned both and they're both great.