differential versus common-mode noise?

Thanks Al and Steve.
I take away that both common and diff noise emanate; therefore common and differential noise isolation is required to properly isolate digital components?
Which noise from the incoming ac line is most disturbing to the digital circuits; ie incites noise within my combination CD/DVD, SACD player-a Lexicon RT 20 from about 2006?

Pt - I recommend using USB interfaces with isolation or filtering.

Analog cables can be isolated using transformers such as:
http://www.empiricalaudio.com/products/final-drive

S/PDIF interfaces should use transformers at the DAC input preferably.

Reclockers can be used to both reduce digital jitter as well as isolation, such as:

http://www.empiricalaudio.com/products/synchro-mesh

Its important to break every ground-loop. There should be only earth grounds to each component, not ground connections between components (with cables).

Steve N.
Empirical Audio

Thanks Steve. I recognize and appreciate the value of the units suggested. However they are a much bigger investment than I'm able to make.Your thoughtful consideration of my question is much appreciated. I feel you are an exceptional asset to those of us posting here. Top of mind for me.

Pt - you can find lower cost alternatives. Just do your research.

First thing if you use cable TV or internet is to get a Jensen isolation transformer for the cable.

Steve N.
Empirical Audio

Thx Steve

Thanks Steve. I'm in my 60's and not tech savvy.
So far I don't use cable TV or internet for
music. Will look into.