So I think the reason your voltage drops is the extra draw you've created by bridging your amp plz someone correct me if I'm wrong. I don't think your amp will do one ohm bridged. If it will, then first thing I would do would be the big 3 to try and get rid on some of the voltage drop. The amp could be shutting down due to lack of enough power but my guess is that your amp wasn't meant to do one ohm bridged.