I evaluated the S5's in my search for a new pair of speakers. My local Magico dealer had the S5's attached to a powerful solid state amp with an extremely high damping factor, when pushed hard, the S5's "came to life". When their "high end room" became available, the moved the S5's into that room and attached it to a tube power amp, and the speakers sounded MUCH better, had more bass, smoother highs and didn't seem to be driven as hard (as with the solid state amp) to "come to life".