Fritz Carrera 7 Be and 300B power amp?

With Fritz It’s the true 8ohm nominal impedance spec that makes it possible.  I suspect it will mostly have to do with room size and how loud to be able to go more so than the amp can’t drive the speakers well.  

Thanks for your help folks. My room is 13 x 11 with the speakers lined up along the long wall. One of the short sides is open to the rest of the house. So small room basically.

Speaker are 5ft apart and I'm sitting 6 ft away

I used to do audio shows with Fritz where we used the Carreras and Carbon 7s with a 10 watt 300B SET amplifier. The combination worked just fine in a room that was 12' x 19', and we got it pretty loud, even trying to intentionally clip the amp. The smooth impedance curve and the benign phase angles of Fritz speakers makes use with low powered amps, including SET, possible. A lot will depend on the how well the amp is designed, the size of your room, and how hard you are going to push the amp.

My one bit of advice, having heard Fritz in hotels and owning similar sized 2-way speakers is that they really bloom in well treated rooms.  Excess reflections will really make these speakers sound a lot smaller and less powerful.

Also, I would think that having the speakers pointed towards the non-wall would help with tuning / treatments.