Doug Schroeder Method, Double ic

It’s very unlikely, Ozzy.

In the case of analog outputs, some designs drive XLR and RCA outputs from separate output stages (i.e., they individually buffer them), and some don’t.

If they do, obviously connecting both would not cause either of the connections to have an effect on the other. (Aside, that is, from the possibility of introducing a ground loop and its negative effects, assuming the other ends of both cables are connected to a single component).

If the two outputs are not individually buffered, the signal provided to the RCA connector is probably the same signal that is provided to one of the two signal pins on the XLR connector. Connecting them both would do nothing for the other signal on the XLR connector, while resulting in at least a slight imbalance in the impedances of the two signals on the XLR connector, thereby degrading the noise rejection that a balanced interface can provide, at least slightly. Also, depending on the output impedance of that component and on the total of the capacitances of both cables, upper treble rolloff of whichever signal is used by the destination component might occur to some degree, and sharp transients might become more sluggish.

In the case of digital outputs, coaxial S/PDIF and balanced AES/EBU outputs would certainly be individually buffered, since their output impedances have to be different. So connecting both would not accomplish the same thing as doubling a cable, which as I’ve said I don’t recommend anyway for digital cables.

Zephyr24069, thanks for your comment.

Best regards,
-- Al

I certainly would Not recommend using both RCA and XLR simultaneously! 

Gents:

Do you twist the wires or just parallel to each other, or to short?

Ie: ” twist “ is like a kimber Kable weave 

jeff

Oddly what you are doing makes sense to a degree.  I know nothing about the interactions of cables and gear.  As in why it happens.  Only a glossy idea of why it occurs.  Ok, I'm uneducated.  Now that that is clarified, I have made the following observations.  I have connected some interconnects between my DAC and preamp, as well as between my Preamp and amp.
One set of interconnects is the Inakustik NF2404
One set is the Genesis by Gary Ko
The other is an inexpensive coax interconnect.

Here is what I observed. 
Between the DAC and the preamp the coax and the Inakustik are hard to tell apart. The Inakustik is better, but not by much. The Genesis is an OMG that is great.  The world opens up.  I use the Genesis there.

Between the preamp and amp the coax, Inakustik and Genesis are hard to tell apart but they are different.  The Genesis is a little thin, so I keep it where it excels.  The Inakustik is more fleshed out and full.  Very clear and accurate.  Pretty neutral but very full.  I like that so it stays between the preamp and amp.   The coax is just there.  Nothing special but pretty darn good for $250.  It is not as clear as either the Genesis or Inakustik.  There is some haze and cloudiness to it.  It is not in use.  

The Genesis is designed around 2 wires on the positive and 1 on the negative. Kind of like your doubling up of interconnects.  Different but similar.  The Inakustik is 2 wires in an air dielectric spread very far apart.  About an inch plus. Totally different geometry.  I am sure their inductance, reactance and capacitance and radically different.  I assume that is why the results based upon where they were used if quite different.  If I were to do a review on either the Genesis or Inakustik and I based the finding on one topology alone, I might find either cable inferior.  If I used the cable in another area, I might find it heavens sent.  Interconnects are tricky business.  It's hard to tell if you are going to get the same results as someone else who raved about them.  From what you are all saying and the links included say, it seems cables are very system dependent.  

Thanks for validating this idea for me.  I got in a fight with one vendor over this very issue and feelings were hurt.  Now I  can't get any more cables at discounted pricing.  I'm just another chump having to pay list price. For that brand at least.  Owe Well.  I really don't need anymore unless I purchase a tape machine.
Rex

@kingrex Your description of the design of the Genesis IC is indeed “different but similar.” The Canare Starquad cable design is even more similar to “Schroeder Method configuration.” The Starquad design has 2 hot, 2 returns and 1 shield. In the Schroeder Method configuration, however, everything (including the shield) is doubled and configured in parallel.