Digital Interconnects - Which one is the BEST ??!!

As you can see, it depends who you ask - for me, optical has typically worked better than coax in the past 20 years.

I can confirm that a "regular" RCA interconnect is not the same as an RCA terminated coax...though some work great as a digital cable and some don't...

As in most things in audio it depends. The only real generality is that optical is consistently an inferior connection.

You will find volumes on the subjects of interconnects here. Given what you have said, I recommend you completely take the question off the table.

An audio system is composed of components. It is the sonic character of those and how they interact that is hugely more important than the connector. The digital or analog source, DAC, preamp, amp, and speakers determine what the sound is going to be like.

Then… when the 85% of the work is done and you have a system that is of the character you want… hooked up with the connectors that came with the component, it has had a few hundred hours of use… you know what it sounds like inside and out; then it is time to start asking which brand of connects you should use… which interconnects might effect the sound in a more favorable way.

As already stated, it all depends on the output of the sending unit and the input of the receiving unit.  Different units vary in terms of which type of connector function optimally.  So yes, a first step is to read up on the two units you're planning to connect, and then try at least a couple of the different connections.

Keep in mind there are two different types of optical, Toslink and Optical Fiber. Toslink would be considered digital cable, this inferior. Optical fiber is network cable, totally different animal. Just so no one is confused.