I have made an attempt to isolate digital from analog. I have Spectron class D mono block amps so we used 3 isolator transformers feeding plugs directly installed for my system. There are two 3 kilowatt isolators for each amp. Then there is a 5 kilowatt isolator divided with separate outs, one for analog and one for digital. Now that it is installed and working I am happy with the system. I started with a smaller isolator for the preamp and DAC but the preamp was starved since I only had 600VA and the sound was hard in the treble and less defined on the bass end. Changing to the bigger isolator relaxed the sound but produced better dynamics and much better bass.
The isolators set on a concrete pad under the house about 5 feet away from the music room so you do not hear the hum. There are dedicated 10 gauge home runs maybe 15 to 20 feet long under the house feeding the new copper wall plugs. I have found copper plugs sound much better than brass.
