Is it just me, or does this sound better? - Page 2

If you take the outer ring from each end of the RCA and test continuity it will show continuity...an outer later of copper covered in this tin foil you speak of.  The tin is shielding and so is the copper.  It's not just 2 wires running parallel next to each other.  Don't just assume something is a piece of crap because of what you see on the outside.  Investigate by cutting it apart and ruining it.  I've NEVER seen a modern cheap RCA cable be unshielded.

I did cut up a couple of cheap av cables, there are just some copper strands under a pvc jacket, 1 of them used tinned copper , not tin foil or anything, tinned copper is 1 material , In tinned copper wire, each strand of copper is coated with tin , it makes the copper last longer, the copper conducters in 1 of these cheap cables are generally 0.75mm2 each.

What is your point?  There is shielding...  It doesn't have to completely envelop the jacket of the inner wire to shield.  Also it doesn't matter if there is a layer of oxide on copper wire after it is soldered to whatever needs to be connected.  It's not going to oxidize farther in with age.  It's not like it's subject to a corrosive environment.  They spread out each strand to make a single layer over the inside jacket, which is plenty.  Conductors don't need to be thick for transport of audio signals.  There is very very little current to have to conduct.  Speaker wires are what need to be thick the higher power you go.

Well i didn't see anything i could call sheilding against rf/emi interference , it's stranded copper wire in a pvc jacket with rca plugs soldered on each end, same with standard power cables 3 or 2 copper wires in a pvc jacket, then with a thicker pvc outer jacket, with a plug screwed on 1 end and a connecter on the other end, nothing fancy, just simple.

I fail to see how the ground shield is will not protect from interference.  There is no proof or measurements that more expensive cables are superior in sound, just different sounding.

It probably just sounds better possibly because of a more powerful amp in the radio versus the computer's.

Does your laptop have a line out?, your get even better sound from the line out rather than the headphone socket.

MacBook has no line out AFAIK.

It's also possible that your improvised cable chain is acting like an attenuator.

Wikipedia has a very detailed article about attenuators.  Some low-impedance phones, like the UE TF10, are bundled with attenuators to filter out noise.