Thanks Jea48 for the info. Please clarify a couple of points you made. First, is the NEC the National Electricans Code?
Second, if a multi wire branch circuit is set up in the manner I described above, please explain how a multi pole branch circuit breaker works. For example, if each hot energizes a separate receptical, is it possible that a short or overload of one receptical fed by one hot would NOT trip the breaker for the other circuit fed by the other hot? If such is the case, isn't that the practical equivalent of 2 dedicated lines?
BTW, for the benefit of others, if a multi branch circuit is legal under applicable Codes and safe, the reason that it could mess up a stereo system is because the AC current is alternating in opposite phases in each hot. That is how 220 v is obtained. I know this because I was an electrician's assistant when I was in college back in 1970. I remember that a 220 v shock can knock your fillings out -- and if that's all that happens, you're da*n lucky.
However, as far as the specific electronic consequence of mixing and matching different phase circuits in stereo gear is concerned, I'll leave that discussion to the electronics techies out there if they think it's worth a comment or two.
Thanks again.