With 2 X 90W Class A+D stereo amp, bridgeable into a 160W mono amp, STA-6 is designed with enhanced even-order harmonic circuitry that produces sonic characteristic similar to NuPrime STA-9, but leaning toward neutral with a slight hint of warmth. The STA-6s spacious, transparent, dynamic and luxuriously textured soundstage has to be heard to believed.