Just heard the Apogees driven by two Sony TA-N55ES stereo amps, (list $580 each) each run MONO, which gives 500 watts per amp into 4 ohms, and has enough current to drive the low impedence. Result? Grand, liquid, clean sound. But of course, it will sound equally well using any powerful, quality, solid state amplifier with a high damping factor, low distortion, and high current capability, regardless of the manufacturer. This restates the previous posting of finding a reasonably priced amplifier with high current capacity to drive the Apogees.