\rHi Mark:
First, there is a Line 2 Pre-amp output that is a pass thru for sources connected to Line 2 input. The amp features automatic source switching where you can have two sources connected. Anything connected directly to line 1 when activated comes on instantly and takes priority over the Line 2 input. Note, Only a source hooked to Line 2 input will play through Output #2. The minor problem would be if you have both Line 1 and Line 2 connected and playing then Line 1 would take priority and play through whatever speakers hooked to Speaker A or B or both A and B at the same time. Line 2 would not be heard through the speakers but would be passed through to the powered subwoofer.
Regarding Bridging the AMP300, you can only bridge one output either A or B. And nothing else. It also needs to be an 8-ohm load. People who want to bridge this amp purchase two AMP300, one for the right channel and the second one for the left channel. The amplifier is a true High Current Amplifier that is 2 ohms stable. I hope that helps.
TL/5301\r