I have a pair of Mac XR 230 speakers I bought new in 1992. They always sounded clear, detailed, and virtually distortion-free. I have driven them with a Kenwood KA-9100, KA-7100, an Accuphase E-303X for a while, and then back to the Kenwood KA-9100 until 2007 in our den. I put the XR230's in a...