A Fet Valve 400R should work great with your AR9 speakers. They will really like the control from top to bottom, and especially the bass control and reach of this amplifier. It provides outstanding results with somewhat "woolly" speakers. The enhanced dynamic range and transient response will help your speakers too. My early B&W 801 speakers have never sounded better than with a Fet Valve amplifier.
Frank Van Alstine
