You don't say what the 'noise' sounds like, so here are a couple of generic suggestions, items that have helped on my SL-3's. 1)Good aftermarket power cords. They don't have to be 'power amp' type, just better shielded than stock. I use NBS Dragonfly's very successfully. 2) At least install an isolated ground duplex receptical & ground your system via this receptical to a seperate ground path (you may have to have an electricion for this). A seperate dedicated circuit is even better, but may not be necessary, try the isolated ground first. Works better & costs far less than 99.9% of the power conditioners out there.