First off, please excuse my ignorance. That said, I have a GK MB500 head (500W @ 4 ohms, 350W @ 8 ohms), an Acoustic B115 cab (250W power handling) and an Acoustic BN210 cab (600W @ 8 ohms). When I have it connected in parallel, the head switches off after playing a bit. I was told at a local music shop to connect them in series, and I have done that. It all works, however I'm not getting the volume I need. I'm assuming I need to change something out, but I don't know where to start. Again, I'm sure this is an obnoxious question to those of you who know the answer, so I apologize.