I think you can do this also by using a balanced isolation transformer to block the inter-chassis DC leakage between components that is contaminating the ground line. I actually have two custom power cords that floated ground. However, I have since learned that floating the ground is a dangerous thing to do since if something in your component fails, when you touch a linked component, you will get a big, perhaps fatal shock. Remote maybe, severe yes. I have since gone to all balanced connections and an isolation transformer (very effective and noticeable sound enhancement) between my RCA output-only CD player. Check out the message archives at Audio Asylum for more background.
No cost Power Cord Upgrade/Tweak
A couple of years ago when I purchased an aftermarket cord, the dealer I bought it from suggested it would sound even better if the "ground was floated". In any event, I removed the ground pin (probably not great for resale) and didn't really make any real sound comparisons with or without ground. Since then, that cord has moved to my CD/DVD player (which is internally grounded anyway) and I haven't really thought much about the aftermarket cord on my integrated. A friend of mine and I were discussing a ground loop problem he is having as a result of cable tv recently and were discussing floating the ground on his amp cord (a DIY Belden cord) but he was reluctant to rip the ground pin out. This got me to thinking about the cord on my amp, which is terminated with a hospital grade Hubbell male end. Thought I might be able to remove the ground pin by dismantling the plug, but this was not the case. What I did do however, was dismantle the male end (easy to do with the Hubbells, and others I assume) and simply remove the ground wire (which was simply inserted into a hole in the internal of the plug and screwed down, not soldered), tape it off with electrical tape and reassemble the plug. The results were pretty shocking to me. Sounded as if I made a pretty decent amp upgrade. Every area of the sound reproduction was improved in clarity, transparency and smoothness, and it sounded as though I'd just obtained a lot more power; the amp took on a much more "effortless" quality and passages which were previously kind of congested and "congealed" really opened up. The improvements were much more along the line of what I would expect from a front end upgrade than simply floating the ground on the amp's power cord. Blacker background, etc. etc. Yes, I know that this is not code and if my house burns down I may have no insurance coverage etc. etc. but I won't be switching back. But I can, quite easily if I want to; simply take the plug apart again, insert the ground into the appropriate space, screw it back down and my cord is original again. I'm not suggesting people perform major surgery on their cords or plugs, but if you have a simple plug to work with, this is very interesting. Just a thought for some of you with similar plugs (that can be easily dismantled and reassembled) and cords that you might want to experiment with.