hello, single end amps are very simply if you look at signal paths and parts count to me this is why they sound so great but they have to run a speaker with high sensitivity to sound there best .You can run a whole speaker of a s.e.t. amp but they role off the treble and bass some what.So mix and match I say ,if you want a tube amp that can run most speakers than your choice is a push pull .they do tend to distort the signal or stretch notes.they do give you a taste of what tubes can do s.e.t.s give you a so much more musicality than push pulls but they dont do frequincy extremes as well.trade offs are what audio is all about