Tubes, typically at least, give a warm sound that had absolutely nothing to do with efficiency of the speakers themselves. Current of your tbe amp would be more important than power. But assuming a typical audiophile 100-200w tube amp you can drive any speaker. For tubes I'd always recommend Magnepans, and which would depend on room size. They will sound great with a tube's warmth (and let's not forget different tubes have different sounds on different amps). And I don't think you specified, I am assuming a tube power amplifier or integrated. If it's pre like my CJ, it would further depend on if you have tube power or SS.
