Is shielded interconnect (RCA) best for connecting FM tuner to amp?

[Jim Audiomisc]

I can understand though why some people are concerned about ground loops, although that's a different kettle of fish.

Yes. All too easy for someone to assume that the cable is doing something 'odd' when the cause if a ground loop.

 

[Jim Audiomisc]

This. Twisted pair cables with shield are microphone cables

More generally, balanced pairs in a sheilding make good sense in various 'pro' environments where you have a *lot*of different bits of kit connected together in a complex array, using very long leads, etc. Domestic situations really shouldn't be like that.

 

[gez]

Standard Deltec Slink are/were a single PTFE-insulated (green and white in all the ones that I have seen), silver-plated copper conductor for each run, positive and return, but for each, a double length was bent in the middle, if that makes sense, so two ends were soldered to the plug at one end, and the middle of the run was soldered to the other plug; the argument being that that made them non-directional.
There are/were only two conductors, no screen.

Was not black Slink just a Kevlar sleeve or some such?

Stand corrected, just had a look and it would seem that the white is soldered to the central conductor and the "green"? (can't see the acutal colour) is soldered to the body/outer ring of the RCA plugs (which just happen to be locking WBT on mine). At one end of each is a "ground" tail, which is presumably soldered to the body of the RCA at that end. So in a sense they are implied as being directional in the sense that the "ground" is presumably supposed to be connected at either the source or termination end for both*. Judging by the way the outer sleeve "ripples" it's clear there's no shield (unless it's very thin and flexible). It's also clear that as well as the individual signal conductor pair being twisted, (i.e the white is multiple individually insluated conductors apparently twisted together), the two conductors also appear to be twisted together down the length of the cable (i.e. whites are all twisted together, as are presumably the "green", and then white and green are also twisted together).

*I seem to recall there was meant to be a correct way to do this according to Deltec, but I can't recall which end they stated.

Correction: Not sure if the two conductors are twisted together, but actually each conductor (i.e white or green) has the following configuration:

2x Multiple (about 5-6) individually insulated conductors (which are twisted to form a "rope"), twisted together.

Which could explain the "ripple" one can see on the outer sleeve.