I have the 820f's . I hooked them up to a Marantz 65w/@ 8ohms. They sound terrible. No only that, but the volume is very low with knob to max. Called Klipsch, I was told I needed a 150wPC amp to power them for the full performance. Using my weak amp resulted in blowing the tweeter. I think Klipsch should make that fact known to customers before purchase. They've been sitting there, unused for two years because amps over 125W are expensive and most do not have a phono preamp.;