Pcoombs, harmonic distortion and DC are two different phenomenon. A UPS or power regenerator like one of the PS Audio units should cure harmonic distortion issues.
Peter_s, I said in my post above that as little as couple hundred millivolts of DC can cause a transformer to hum or buzz.
Peter_s, I said in my post above that as little as couple hundred millivolts of DC can cause a transformer to hum or buzz.