I received my information from conrad johnson as I run their electronics and they suggested short inteconnects.....short as possible........over speaker cables. With long interconnects I believe it is recommended to use a balanced design; not sure what the break point length might be. Conrad johnson designs their equipment with single ended (RCA's)only. I believe their manual states that interconnects are more susceptible to picking up interference than speaker cables. But I have not experimented with this only taken their advice.
Chuck
Chuck