there are a few amps that run Class A up to between 10 and 25 watts before switching to Class A/B. But 25 watts in a 90db efficient speaker is about 103db, which is pretty loud on an average. In fact, at normal listening levels, you might not hit 103db even on peaks or heavy bass notes. Those amps dont use as much power when idling and dont get quite as not. My Dussun V6i, Musical Fidelity M3, Nobis Convigore and Classe 100 all run that way and sound pretty good.