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).
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).