Hi Mojo and Bugbitten,
Do NOT connect the output of your amplifier's or AV receiver's left and right channel speaker outputs in that fashion. You could damage or blow out one or the other (or both) amplifier channels.
If you both amp outputs to the VP150, the left channel amplifier would be driving not only the VP150, but also routing its output power back into the output section of the right channel amplifier and vice-versa. Not a good idea!
The way to do this is to use the pre-outs (low-level) for the left and right channels. Get an adaptor with left and right RCA female input jacks and a single female (or male) output jack, then connect the combined (mono) low-level signal into one of the unused amplifier pre-amp inputs. The amplified output of that channel would then be mono. In some respects, the pre-outs should be buffered so there is no interaction of the left channel preamp with the right.
But at least you won't damage the power amplifiers this way.
Regards,
