http://www.diyaudio.com/forums/solid-state/162408-900w-h-class-pa-amp-limiter.html Power suply 0,+/-60V,+/-120V. THD 0,03% 20-20000Hz on 900W 4 ohms. All new brand amplifier use 4 pairs of 1943/5200 evan for 1900W 2 ohms in their specification. I dont want to go tnat much.