regarding cable, I want to chime in a bit..
I used to run a small, home made, RCA interconnect business about 18 years ago or so... for quite short period; only about a year and sold about 20 pairs. Until I run out of time due to my office work. It was started with my DIY effort to get cheap quality products. I experimented with few types of cables... RF cable, Cat5 UTP cables, magnet wire cable, Belden 89259, etc... and used Belden 89259 for my cable business. (Note: if I'm not wrong, this is the same cable used by Blue Jeans cable)
Cable material do have effect in sound... but there's really no magic here, they are all could be explained in physics...
For example cable that is used for very high frequency (2.4GHz for example) transmission sometimes made with aluminum as the core and the copper only on the most outside surface (if you ever heard about skin effect... they really do put this into consideration for economical reason... since having all copper material would be useless for such a high frequency transmission). Now if we compare this cable with all copper cable of the same AWG size, for audio band (20Hz-20KHz)... You will easily hear the difference...
Cable core diameter and material makes difference... for example for speaker cable... if you compared 10AWG of single core cable vs 10AWG of multi strand core.... you could hear that single core big diameter cable would sound dull. Once again, law of physics could explain it...
Different cable material of quite close characteristic say 26AWG stand, OFC, non-OFC, pure copper or silver plated copper... would not be much different (if placebo really makes us believe we can hear the difference).
BUT... There is also another thing could really make them sound different.... that is how they are terminated....
If let's say you have two cables, with the same termination end connector, one with good solder joint and with non-perfect solder joint (for example cold joint).. you could hear the difference... I don't need to explain why; this could be searched on the net...
Talking about termination, different connector material and size could make the difference... but these are all actually related with how perfect the termination could be done. For example in my case... I tried cheap RCA connector which has thick metal... It was sooo difficult to get a good solder joint with it... why? because the thickness of the material absorb and spread the heat very easily... so, the result is non-prefect joint... and bad sounding... It is not as good as the same cable terminated with Neutrik Profi RCA, which is very well thought construction with thin soldering point and thus easy to make perfect solder joint. Then I tried compare Neutrik Profi with more esoteric connecter, Eichmann Bullet Plug RCA.... Perfectly terminated, both, ...no difference...
Sooo... I want to come to my point... cables... based on factors I mentioned above.... IMO... could sound different...
(And frankly... I sometimes worry if cable that is sold too cheap, would the manufacturer made correctly or not... terminated correctly or not... )