The QSC PowerLight PL4.0 is a high‑output touring amplifier designed for professional sound reinforcement, delivering strong, clean power while maintaining the low weight and efficiency that defined the early PowerLight series. Using QSC’s switch‑mode PowerLight supply and a 3‑step Class‑H output stage, the PL4.0 provides 900 watts per channel at 8 ohms, 1400 watts per channel at 4 ohms, and 2000 watts per channel at 2 ohms, with bridge‑mono capability reaching 2800 watts at 8 ohms or 4000 watts at 4 ohms for subwoofer duty. It includes clip limiting, selectable low‑frequency filters, and comprehensive protection against thermal overload, short circuits, and DC faults to keep both the amp and connected loudspeakers safe during demanding shows. The amplifier’s rear‑to‑front cooling, Neutrik combo inputs, binding‑post outputs, and DataPort integration make it well‑suited for touring racks or fixed installs, offering reliable performance with tight low‑frequency response and clean headroom for mid‑ to large‑scale PA systems.