hospital grade or commercial grade receptacles ?

Eldartford:
I guess there are more colorations in Ivr system sound after the change.

Paradigms preclude progress! Keep an open mind and above all open ears!!!

"The only downside was that I noticed some softening of the micro-dynamics, but I only noticed it when using unbalanced interconnects."

I don't know about you Irv but sometimes too much leading edge on the transients of the micro dynamics can sound artificial. I kinda like it when the microdynamics are softened, just a tad.

Seriously though, you might benefit just a bit if you could just eliminate your preconceived institutional thinking and just trust your ears. Often times as not what is seemingly snake oil can fool you. Being skeptical of many things audio I can say with a straight face that I have definitely heard differences in outlets and powercords. I really don't know why this should be but it is real. Don't dismiss Albert Porter too readily, he has invested many years and has listened extensively to many products. You don't mean to say that we're all a bunch of fools and are being duped by a group think plecebo effect, do you?

Irvrobinson;
Are you saying that an isolated ground system does not need to use isolated grounding receptacles ? I thought
(possibly incorrectly) that they were made differently.
Something with the way that the strap or ears were connected to the case of the receptacle for grounding purposes. As I said, I don't know much about this. Just trying to get it right the first time !

Saki70, you are correct in your understanding of the difference between the isolated ground and non-isolated ground receptacles. If you are going to the trouble of installing an isolated ground cable runs, it's probably worthwhile to finish this off by keeping the isolated ground completely separated from the bare grounding wire loop. But, if you are using Romex cable rather than metal clad cable (or if you are installing into plastic wall boxes rather than metal boxes), and if you are using a dedicated line going to a single outlet, the use of an isolated gound receptacle probably is not as important as it might otherwise be because you are already isolating everything back to the grounding bar of your electrical panel. (Caveat: This is based purely on the reading that I've done and from what I've learned from more knowledgable folks posting here in the past; I don't claim expertise and I'd be happy to be corrected by someone who is an expert.)
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Saki70... orange is the industry standard color to signify isolated ground circuits, but outlets with isolated ground construction (phase, neutral, case ground, conduit ground) can be acquired in many colors. You only really need orange for something like an electronics lab, where some test equipment needs a very clean ground (for voltage reference purposes, perhaps) and you don't want to accidentally use a conventional circuit. You might get inconsistent results.

For dedicated audio circuits isolated grounds are sort of like belt and suspenders, if you know what I mean. In many cases you won't hear the difference. When you're installing new circuits it's not that much more expensive, and you just might get lower noise. So why not? When I did mine I didn't think twice about it (though I had to get ivory isolated ground outlets special ordered, so we lived with orange for a couple of weeks).