I have been listening to my Decware 300b tube amp for a few months now. At 8 watts, I have them paired with Klipsch Forte IV at 99db efficiency, and this set up has been sounding great. This morning I connected a pair of Sonus Faber Electa Amator speakers, 6ohms at 88db of efficiency. They sound fantastic, with more weight and depth. I understand there is a huge price difference in the two speakers, but aside from that, if I am getting 80db of volume at my chair, 8' away, what is the draw back of using lower efficiency speakers with SET amps, so long as the volume is sufficient?
It comes down to your choice of music as well. Here.. listen to this track by Icelandic composer, Hildur Guðnadóttir to check bass control and so on of your drivers. Turn subs off and just crank the speaker up to about ~90 db (Don't be shy, our good lady, Hildur is merely here to check for a minute if your stuff is any good or not). Compare back to back with a pair of Schiit Tyr Monoblocks and the Decware weak sauce fleawatt on the Electa Amator. When the Decware cries and runs to its daddy, i.e., fizzles out, i predict that i will see it on the Audiogon marketplace for sale real quick. 😁
https://www.youtube.com/watch?v=B7sj_XJJ9U8
But, If you are listening to some weak sauce track with a twangy dude wailing to a single string at 65, 70db about how a gal broke his heart into just a few million pieces..... i suppose your Decware should be just fine with the Electa Amator.