"QSC expertise is also evident in its advanced manufacturing and quality control processes. The company manufactures in its 81,000 square foot, state-of-the-art facility, located in Costa Mesa, California. Utilizing a compliment of demand planning, parts procurement, operations and logistics, computer-controlled precision assembly, and rigorous testing and control, the QSC facility is designed with build-to-order flexibility, giving the company unprecedented ability to respond to customer needs while keeping both parts and finished goods inventory at well-maintained levels. Select partners in Asia provide additional manufacturing."
That's from their website and here's a pic of the back of the amp. If you look on the white card, it says Made in USA. I don't have mine anymore, but it did say Made in USA on mine as well.
http://www.qsc.com/resource-files//productresources/amp/gx/q_amp_gx_img_rear.png