Class A+D stereo power amp with 2x120w, or bridgeable into a 290w mono amp. The class A input stage gives the amp a warmer, tube-like sound to go with the high power class D output stage. In my system the STA-9 provides very good imaging, wide and deep soundstage and tight, deep bass without the dry/sterile sound of some class D amps. Outstanding performance vs price ratio.
See very positive reviews on the AudioCircle forum, and web sites AudioAficionado dot org and Totallywired dot co dot nz.
Purchased new April 2016 and used lightly since then due to a major house move.