I don't know what you call cheap, but I have had $300 qsc 1450 behind mmgs, and it put out clean, undistorted sound at concert level. The lights in the house were dimming with pounding bass drums. I had an adcom preamp between source and qsc. Mmgs were without fuse and sounding good, and the qsc was not even at 1/2 full volume.
It's cheap, something to try.
It's cheap, something to try.