I used to run two lines to my listening room. One for analog and the other for digital. I was advised early on that this was the best way to go. Recently I have been advised that it is best to run everything from the same line. Both Keith Herron and A J van den Hul recommend this approach. Here is an excerpt from Mr van den Hul's Tips and Hints for better sound:
8-4 Power all equipment from a single wall outlet
It’s best to use one single wall outlet to power all equipment by means of a multiple socket mains distribution board. This
avoids large ground loops along the interconnects and the power cables. The power amplifiers must be connected as close
as possible to the mains input of this connector block. The lower power consumption equipment can be connected more to
the other end of your mains connector block.
I have read in TAS and elsewhere that you should have dedicated lines for power amps at least. Also, some people say that power amps should not require any conditioning at all.
I find this all rather confusing and would like other peoples views on the subject.