I think that you will find some excellent choices in the Balanced Power Technologies line. I am also very pleased with EquiTech though they don't have as many offerings at as many price points. Both are true balanced power units. Based on the research I did at the time, I wouldn't get anything else. Both are available used on the 'Gon. BTW if this is part of an HT room you won't believe what one of these will do for your CRT/plasma/LCD display.
There is little doubt that conditioning your power will improve your sound by reducing the noise floor. And as also has been suggested by filtering the line noise from the digital unit(s). As Bob suggests, improving power cords also helps, get one (or more) that is specifically designed for digital front end sources - again there a lot of them for sale here.
Depending on your setup, ie if you are feeding from a transport to a DAC, you might also consider trying a different SPDIF cable to see if some of the unpleasantness you are hearing is some kind of smearing or jitter
There is little doubt that conditioning your power will improve your sound by reducing the noise floor. And as also has been suggested by filtering the line noise from the digital unit(s). As Bob suggests, improving power cords also helps, get one (or more) that is specifically designed for digital front end sources - again there a lot of them for sale here.
Depending on your setup, ie if you are feeding from a transport to a DAC, you might also consider trying a different SPDIF cable to see if some of the unpleasantness you are hearing is some kind of smearing or jitter