What's better, one conductor or two conductors for an RCA interconnect?

So how does the RCA connector accommodate 2 connectors(positive and negative) and a ground wire.

@jumia Simply by careful soldering.

The second standard is Differential input RCA which is balanced like XLR and uses two wires to send signal on wire one and inverted signal on wire two. No shield is used.

There is no standard for balanced differential amplification using an RCA connection. If such a thing is used expect a bit of the Wild West.

@kijanki I try to always use caps in the spelling too.

@jumia Look at it this way. If the signal is passing through the shield as it does when only the shield and center connection is present, then the construction of the shield and any noise to which its subjected to will affect the sound, some of it possibly in the form of added intermodulation distortion as the noise is impinged on the signal.

When the shield is separate from the signal this won't happen so it sounds better.

The actual technical description is more complex as you know; this is the Cliffnotes version.

Let us change the problem to a phono cartridge and a pre-amp. By your understanding, even if one side of the phono amp input is grounded, the system is "differential", and hence will receive the full benefits of twisted pair wiring. That is wrong. I noted that @atmasphere who supported you above uses a true differential input on the phono inputs to his preamplifier (for improved noise rejection).

@deludedaudiophile  To be clear no direct line can be drawn between single-ended and balanced lines as they are mutually incompatible. A phono cartridge in most tonearms is a balanced source, but usually its operated single-ended, leaving you with that weird ground wire that has to be hooked up to avoid buzz. When you run it balanced the ground wire is gone, instead there is the shield of the tonearm cable with a twisted pair inside, much like the tonearm tube itself.

FWIW dept.: the use of capitals is to honor the people that did the early research; Hertz, Ohm, Volt, etc. are all names of people but 'kilo' and 'mega' are not- they are multipliers. So you see kOhms, kHz, kV or mV (milliVolts). Anything else is either ignorance or being sloppy, and yes, I've been there.

@jumia 

@kijanki got it right in one. @deludedaudiophile , you are ignoring in your response that an RCA cable with a twisted pair and shield is in fact a coaxial connection. If the cable is very long this doesn't work so well, but in the shorter connections that are seen in household hookups it works just fine. For longer connections of course balanced is the way to go.