Several of us found out that DAC’s and amplifiers can be very sensitive to the quality of power, almost to the point that when it is a “bad electricity day”, some of them can be almost unlistenable. Certain DAC’s (such as Museatex Idat-44, or Metrum Octave), are more sensitive than others. For certain people, the only solution can be late night listening. Installing AC filter strips or power regenerators seldom helps, since, at times, dynamics or even sense of naturalness can be compromised.
The quest for finding a high-quality power regenerator (like the APS PurePower) can easily get expensive and tiresome.
At times, it’s far more adviceable to use very high quality power cords, which act like filters, rather than conditioners.
Other times, solutions could involve using battery-based supplies.
The link will bring you to one of the most fascinating (and fun) discussions on the subject, from GoodSoundClub (website and forum held by “Romy the Cat”).