linking channels?

If your amp doesn't have a bridge switch like most newer amps, the way to bridge it is to get the same signal into both channel's inputs. A bridge mode switch doe sthe same thing, just internally. It takes the input of channel one, and parrallels it to the second channel's input. In fact, it used to be common practice to bridge seperate single channel amps by splitting the input signal into them, and taking the output of both (or all) and sending it to one speaker cab. If I'ma bit confusing, just say...I don't seem to be making much sense to myself right now.

 

You're right Paul, something doesn't make sense.
You can only safely bridge amps that have bridging capability. Connecting the two inputs does not bridge the amp. I would never take the outputs from 2 amps and drive a single speaker.

If he was combining the inputs to drive both amps but each amp's output drove a different speaker, then he can get the power from both amps. This is not bridging, however.