I need to get to the bottom of this, but on the webpage for my Usher 6381's it says "goes better with SS amps". I assume, perhaps, that it's because their rating (87db/8ohm) isn't the easiest to drive (but not THAT hard, I would think??). Still, it's a curious thing to note. I've been curious about tube amps but have always stuck with SS partly due to this suggestion.
The 87db efficiency may or may not be a factor depending on the size of your room, the dynamic range of what you listen to, and how loudly you listen. But I suspect other factors are involved as well.
First, I see that they are rated for 150W; a 150W tube amp will tend to be expensive (quite likely more expensive than the speakers for a good one), as well as big and heavy.
Also, it could be that the speaker impedance drops to low values at some frequencies, which would make them easier to drive with a solid state amp (due to its typically lower output impedance). That is not indicated either way in the specs I looked at. And it could be that the speakers require the better bass damping and control that goes with that typically lower output impedance.
A lot of these considerations potentially relate to the original poster's question as well, and make it difficult to give an all-purpose answer.
Regards,
-- Al
