[RodB]

Yes, you can look at the schematic. When the output tube screen grid is connected directly to the plate then it's wired as a triode. Cathode bias is developed by a cathode resistor of around 150-220 ohms usually bypassed with an electrolytic capacitor. Fixed bias is developed in the power supply usually with a voltage divider resistor connected to the center tap of the power transformer. Output power is found either by ohms law or looking at the tube manual for the output tube. The specs will list 2 or 3 configurations and give the output power for a specific configuration. In push-pull you double the value. For instance if it gives a value of 4.2 watts that would be 8.4 into the opt and 8 to the speaker. Transformers are about 85% efficient.