power up and shut down

Have you tried a different brand interconnect?

Good suggestion Jc. It may not even need to be a different brand, sometimes just a different cable can be enough to find the culprit.

I once bought a set of RCA based interconnects from a guy that was going crazy trying to find the source of noise in his system. He had bought various PLC's, purchased all new high dollar balanced cables, etc... As it turns out, the source of the noise was one of the cables that i had purchased. One of the factory soldered connections was poorly done and the result was noise. While he was upset that he had pulled his hair out and spent so much money trying to solve the problem without checking something as simple as this, he was glad to finally find out what the source of the noise was. Let's hope that is all that is wrong with your system, as it would be a quick and cheap fix. Sean
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PS... Have you tried plugging all of your gear into one comment outlet ?

I do have everything (sources and preamp) plugged into a single surge protector. I'm going to try pulling all the interconnects and re-installing...