As i understand it the single ended amps tend to be the low wattage midget amps that are used with the ultra high efficiency speakers. Never heard one but i hear the midrange is so killer it makes up for some weaknesses at the other extreams. Check out the VTL as they are switchable between triode and tetrode and each of those modes offer some advantages for different types of music. Sayas, i compared an aleph with an ARC VT100. Sadly, reliability issues aside, there was no comparison. The Aleph was great on it's own but the ARC walked away from it in top end smoothness and midrange in a side by side comparison. You're either a tube guy or you aint i guess.