I have the earlier BB800 and it's the only class D amp that i've ever thought came close to having some real wallop about it. I've tried a few of the usual suspects (Genz Shuttle 9.2, GK Fusion500, Mesa D800, MarkBass EVO1, Darkglass M900, Genzler Magellan800) and moved them all on. But I've had my Quilter for 3 years now and it's staying. Total clean headroom and muscle......