Gary,
So far it breaks down like this. Yes, the G5 seems to be more sensitive to whatever is going on here. It could be ground, it could be the current itself picking up the hum and interference from the rest of the stuff in my house.
FOr now using MOTU 828 works out okay because the noise that I do get is only audible when all the levels are cranked up to maximum. Same with using Digi 002. I think that has to do with the fact that those interfaces have their own transformers. If on the other hand I try to use less expensive interfaces like the Edirol FA101 things get pretty nasty. I'm lucky enough that my dealer lets me take anything I like and try it before buying.
OR at least he never gave me a hard time exchanging whatever I buy if there are any problems.
ONe thing that really throws me off in all of my assumptions is that when I connect the Edirol to the G4 I get the same low level of noise that I do when I use Digi 002 and MOTU 828. THe phones out on the G4 is also noisy.
So on one hand it seems like the G5 is definitely more sensitive to any kind of interference but at the same time there's definitely something going on power wise that creates that interference to start with.
Both will need to be taken care of.
I won't really bother connecting my synths yet just to keep things simple. Some of them are over ten years old so regardless of power issues they still have a bit of noise on the outs. I just don't want things to get anymore confusing than they are already.
-ED-