Per the QSC Audio Forum, which I had never heard of before this, the answer to the question Where are QSC amps manufactured? was answered as follows (ON MARCH 1, 2007 caps for emphasis):
Hi dominik
All but the RMX, GX, and ISA series amps are manufactured at our facilities/headquarters in Costa Mesa, California. The RMX, GX, and ISA amps are designed by QSC but built for us by a company in China.
Bob Lee
Technical Communications Developer
QSC Audio Products, LLC
Fellow, Audio Engineering Society