I just bought a Jcm800 4010 that has a Vintage 30 installed instead of the original. It's 16ohms-I was thinking the original was probably 8ohms. Is it okay to run at 16ohms as long as the selector is on 16ohm? On a side note, how do you tell if the v30 is made in China-it says Celestions International...Suffolk, England on the back. One more side note-there aren't any spring retainers for the tubes-it has El34's so maybe the original ones don't fit. Is it suppposed to have them? Any good sources for Marshall parts? Ps, I haven't had a chance to open 'er up since I brought it home-I'll have to report back-sounded really nice when I tried it out-the cleans were way better than expected and some nice crunch.