I'm glad to hear your speakers are healthy. You are suggesting that perhaps the Denon is being taxed when you turn up the gain. I can understand your Denon getting taxed when connected to the speakers but it should not be getting taxed when it's connected to the MPS-1. The MPS-1 should have a very high input impedance (>100KOhms with very small capacitance in the order of hundreds of pF or less). But even if the Denon is being burdened, this still doesn't explain why the MPS-1 is shutting down. I don't mean to scare you but I strongly suggest you don't over-look this. You may have discovered a marginal design and/or marginal components that could get worse with use. And it could come back to haunt you after the warranty has expired. Along these lines, find out how Emotiva burns this product in and whether or not the burn-in covers this sub-system.