A/B testing of RCA interconnects using Y splitter- Thoughts?

That's exactly A/B switching. You must have that confused with ABX, where each button push changes but you don't know to what- A to B, B to A, or no change which is X. Waste of time since the whole point of my story is that differences are so large and easy to hear its silly to even doubt. But also because of the unstated corollary, that if the differences aren't large and easy to hear then who cares?! The whole point is to build a system not conduct some pointless science project! For this purpose if you can't hear any difference, not sure, etc, that's just great. You can save a lot of money.

It was an interconnect, but you've latched onto another one that doesn't matter. Really does not matter. Could have been a power cord or speaker cable. Could have been the inch of wire that is a fuse. Or streamer, router, do you get the point now - any wire.

So, nix your splitter idea. Hook up a wire, listen. Change wire, listen. One sound better? That's the one. Done. No difference? Done. It really is that simple.

The 'Y' or Wye splinter of an output with one of the cables unconnected has two small problems.a] the cable capacitance of the unconnected one adds to the one being tested.b] the unconnected one might act as a hum, noise, interference antenna.

millercarbon

.... You must have that confused with ABX, where each button push changes but you don’t know to what- A to B, B to A, or no change which is X ...

No, that is not at all how an ABX test works.

In an ABX test, there are two sources. One is ’A’ and the other is ’B.’ They never change. You can go back and forth listening to them as many times as you like. ’A’ will always be ’A’ and ’B’ will always be ’B.’

’X’ is the unknown source for the test subject. It is always either ’A’ or ’B.’ The goal of the test is to determine if the listener - under the test conditions - can reliably determine whether ’X’ is ’A’ or ’B.’ The listener can switch among 'A' 'B' and 'X' as many times as he likes to help him identify whether 'X' is source 'A' or 'B'.

Here’s a link to an ABX comparator that offers more detail.

It amazes me how many people will dismiss the value of an ABX test without even understanding it, to say nothing of not having any actual experience with one.

This will degrade the sound totally.

What is it that:
will degrade the sound totally ?