The amplifier is upgraded from 8w in the 350 to 20w in the 780 though. I've heard the difference between the 850 (with 20w amp) and 350 and it's significant. I'm assuming that is mostly the speakers/amp rather than any processing and want to know if the 780 has these same "guts" and therefore a similar sound (less the simulators that only the 850 has). It looks like the back of the 850 is solid while the 780 has an opening. Wondering if anyone has seen the 780 that can comment on whether it's cabinet has a more solid construction, or if it's identical to the cabinet you can add to portable units like the 350. Really would like opinions of those who have seen/tried one. Not saying you haven't pianicaman350. Thanks all!