I've never used RCA interconnects to transfer digital signals to a DAC. But theoretically, cables which are most resistant to RFI/EMI would least likely to interrupt any digital signal stream. My first choice is to use optical cable because it's completely immune from RFI/EMI. In my experience, the results are error-free streaming from my Apple TV at it's highest spec digital steaming capabilityy, (IRC 24 bit 48 MHz and my Sony UDP 1000ES disc player at it's highest spec into the internal DAC on my Anbthe STR pre-amp. And so far, I've heard no difference in SQ from more expensive streaming system. I'm 71 years old/; but my most recent hearing test about four years ago reveled that I can still hear 20KHz audio signals. I consider myself extremely lucky because I spent sixteen years in ambulances running a high volume of emergency responses with loud Federal Q sirens and later, electronic sirens without wearing any ear protection.
How crucial is the quality of a digital cable?
I recently purchased a Cambridge Audio CX 81 integrated amp. The analog inputs sound great, but I find the internal DAC to be a disappointment. It uses the ESS Sabre ES9016K2M chip. I use a mid-level Rotel RCD 951 CD deck as a transport via the digital coax. I also hooked the deck via the analog out, just to compare. The analog interconnects are entry level AQ's. The digital coax is an Amazon purchase in the $15 range. I find the internal DAC of the 20 year old Rotel to be superior to the new AX 81, when doing an A/B.
What then confuses me is that the Blue Tooth streaming from the amp is quite good. It is HD aptX, 24-bit/84kHz capable. But, wouldn't that also go through the same internal DAC? Could it be the mediocre Amazon digital coax cable? I always assumed that digital cable quality was less significant than analog cables. Just bits and bites, right?
If someone knows of a decent digital coax for under $50, I would be very grateful. I would also appreciate any advice on an entry level power cord for the amp. Can a decent power cord be had for under $100?