In addition to the incoming power do you have a dedicated circuit for your system? Not sure if that would help but when I added 2 for my system the noise floor dropped significantly. That being said my incoming voltage varies from 119V to 127V and I hear no differences at either extreme. Before I knew my voltage was all over the place I added a 2.4KVA balanced isolation transformer that lowered the noise floor even more. Since then I have taken it out because there was a 2V gain on the output and at 127v I had 129V out. Can't be good for my tubes. Personally when funds permit I'm going to look into voltage regulators.
Sometimes my system sounds great, sometimes awful
Does this happen to any of you? Sometimes I find that my system sounds great, but sometimes, with the same record, same everything, it sounds awful! It drives me nuts. Do we hear differently depending the time of day, our mood, heat, cold... other circumstances? Whenever I think I have to replace a component or trash a cable I tell myself to wait until the next day to overcome upgradetitis.