I just upgraded my HT backbone to a B&K Ref 31 and a Parasound HCA-2205A. Previously, I had a Denon AVR-2500 analog-only HT receiver. I have now connected my CD player, DVD player, and digital cable box via digital coax connections to the Ref 31 using high quality inteconnects. I have noticed that I get an audio drop-out whenever there is any kind on voltage disturbance, such as switching on/off a ceiling fan or when the furnace fan switches on or off. This only happens when using a digital source. The evidence suggests to me that this is related to noise on the AC. I'm currently using an inexpensive (now undersized) surge suppressor on the system. Do you think a better surge suppressor would help, perhaps one with some regulation capability?