I wouldn't agonize over it.
Good lord, there's anough psuedo science, half truths and technobabble flowing about this hobby that most people with little or no "real" knowledge of electronics in the real world can easily be driven to near terminal cases of audio nervosa. That's pretty much what drives this industry. Nobody makes any money if everyone is satisfied with their equipment.
I seriously doubt you are experiencing any detrimantal effects as long as you are using fairly well shielded interconnects (which, BTW, don't cost a fortune) for your line level signals (and phono, if applicaple). Likewise, speaker cable need not cost a fortune for good performance either.
On thing I might suggest is that you might want to route any AC power cables away from the interconects if possible. It MAY make a slight difference if the shielding is spotty. Then again, it's also highly possible that this would not make any difference either.
So, enjoy your system if it sounds good to you. If you want to look for problems, either real or imagined, this is the hobby to be in.