Will I damage my DC electronics if I don't quite match voltage and amperage using a AC/DC converter?

I have an old 8mm video camera that I want to use to transfer to DVD but I can't find the original ac/dc adapter for it. I have one for another camera with the same amperage (2A) but the adapter puts out 7.4 V instead of the 6V rated for the camera I want to run. How close do I have to get in voltage [uming the polarity matches] without causing serious damage? What if I used a cheap wall-wart that puts out 6V but only a measly 300mA?