Arbuk, I spoke to one of the designers at Edge Electronics about the RCA vs. XLR situation in relationship to their gear in particular. In the Edge circuits, the unbalanced/RCA topology actually is quieter than their XLR prototype counterparts---exactly contrary to the vogue opinion of many so called High Enders.
According to Steve Norbert (spelling?-Norber[?] at Edge), the extra components to make the true balanced topology ADDS noise in the Edge amps rather than reducing it.
The interconnect length issue does hold an advantage for the balanced/XLR method. No question, there. An unbalanced/RCA, vacuum-tube pre-amp, for example, will require an output buffer stage to lower the impedance and strengthen the signal output for a long RCA interconnect run to the power amp--say, longer than about 2.5 meters or so. Adding this buffer stage will increase cost and perhaps deteriorate signal integrity.
So, you are right in your observation that many experienced A'goners (and reviewers, too) have very fine systems that use RCA through out.
According to Steve Norbert (spelling?-Norber[?] at Edge), the extra components to make the true balanced topology ADDS noise in the Edge amps rather than reducing it.
The interconnect length issue does hold an advantage for the balanced/XLR method. No question, there. An unbalanced/RCA, vacuum-tube pre-amp, for example, will require an output buffer stage to lower the impedance and strengthen the signal output for a long RCA interconnect run to the power amp--say, longer than about 2.5 meters or so. Adding this buffer stage will increase cost and perhaps deteriorate signal integrity.
So, you are right in your observation that many experienced A'goners (and reviewers, too) have very fine systems that use RCA through out.