OK, read the old sticky on OHMs. Great post. Read some users questions. Still left wondering though. This question is in regards to a single speaker. Lets take one amp head- rated at 8ohms for a single cabinet, but 4 ohms for two cabinets. So you get and 8 ohm cab. But if you use the second speaker output, you now have four Ohms operating (based on the formulas ive seen posted). But can the amp head, SAFELY use a single cabinet by a single of its outputs on a 4 ohm cabinet. It says the head operates at 4 ohms sometimes, so how does it know. I've seen in the articles that if the single cabinet was 2 ohms the lack of resistance would push back to the head. So i am confused i guess how the head would work with a single speaker or cabinet.