I play my Ibanez SRX 650 and Ampeg Big Stud (vintage 70s) through an Acoustic B200 combo without an extension. I'm considering a 2x10 or 4x10 extension cab, cuz the 1x15 just doesn't have the punch i want for funk. anybody using one? love it? hate it? I know the external speaker jack is wired as series so lower ohms = more volume, right? (its rated 200W at 4 ohms, the internal speaker is 4 ohms) I'm happy with the current volume, I just don't wanna decrease it. Peace.