Does Size of Amp Matter for Pinch Harmonics?

I have an RG350DX guitar and just a wee amp and I can't seem to do pinch harmonics anymore. I used to have a bit bigger one, and I could do them fine on there. The pinch harmonics I want out of the amp are George Lynch or Eddie Van Halen -esque. I don't want just the little pings that are comming out of it just now.