The Threshold Stasis amps were among the first high current designed amps available… ~1980. I owned a Threshold s500 for nearly two decades. When I replaced it with a Pass x350 the Threshold sounded completely anemic and tinny without a real midrange. Subsequent Pass designs have improved the sound by leaps and bounds. While I loved the Threshold at the time. You couldn’t give me one. If you want sound quality fast forward a few decades.