Doug Schroeder Method, Double ic

I will add that I do not find your result surprising, as you have made an extreme double IC. Schroeder Method seems to be efficacious with all ICs, regardless of quality, but the pedigree of the IC makes a pronounced difference in the rend result. Think of it as leveraging the quality/character of a single IC. I do not find the fundamental characteristics of ICs to skew toward an entirely different set of characteristics when doubled, but rather  to be vastly intensified. 

OK- I tried this in three applications.
The phono cartridge is a balanced source and low impedance. I used the Atma-Sphere MP-1, which supports AES48. At the input of the preamp, this isn't a big deal but at the output it is. More of that coming up.
The phono input didn't seem to make any difference with an additional cable in parallel. BTW this would have cut the resonant frequency of the cartridge and cables in half (but that resonance is well into the upper 100sKHz with dual cables).
In the CD player however the difference was an immediate improvement. The CDP is single-ended.
On the output of the preamp I could not make out any difference. The connection to the amps is 30 feet long, but the preamp supports AES48 and can easily drive 100 feet. So the additional capacitance and connection resistance is a non-issue for it.

At present I don't have any balanced gear that does not support the standard so I can't comment about that. My surmise about what is happening here is that the connection is what is important- it would be interesting to try just running dual connectors into a single cable (sort of the opposite of a Y adapter) and see what happens.

atmasphere....that’s interesting. I have all Ayre balanced, and am using Doug’s cables and I hear a definite difference....not questioning you, just my 2 cents.

I had received 6$ Y splitter from Amazon one hour ago.

I am trying with Crystal Cable and Silnote Morpheus RCA cables.

The soundstage seems to get wider.

But I need two or more days to give any definite opinion.