Doug Schroeder Method, Double ic

I will share hear what I just posted in the comments section of my article which is linked above. 

I wish to add to the body of knowledge about the Schroeder Method, as well as clarify some misinformation that is forming around it. I have found also in experimentation that it is efficacious in additional applications including a digital connection, an XLR connection, and connection between dedicated preamplifier and amplifier(s). The balanced (XLR) connection was the first to be tried, as a natural extension of the original RCA assembly. Next was a twin XLR assembly acting as AES/EBU output from a transport to DAC.

The final iteration relating to preamplifiers and amplifiers must be prefaced with the necessary warnings that caution should be exercised in regard to some amplifiers which are NOT suitable for using the Schroeder Method (double interconnects) as it may cause them to oscillate, making them unstable and damaging them, and or speakers. Again, as always has been said, this is a DO AT YOUR OWN RISK activity. Please consult your equipment manufacturer if you have questions or concerns about the suitability of this activity.

The final iteration was a dedicated preamp to amp setup which worked as splendidly as all the others. I discussed this further in the soon to be published review of the Belles ARIA Preamplifier and Mono Block Amplifiers.

Does multiple parallel transmission lines exist as a cable, of any kind? is there a a history in this area?

This is apparently a nordost cable, in this image.
 
The idea of parallel transmission lines is as old as the transmission line idea itself.
The trick is.... can it be made to work. It depends. On a lot of things.

One last point which I do not believe has been emphasized enough is that the longer the interconnects, the lower the characteristic impedance of the cable. Doubling a cable halves the impedance, and I have been avoiding longer cables (i.e. I have only worked with 1m interconnects to date) in doing the Schroeder Method, as I do not wish to encounter a situation where the output of the preamplifier (whether internal to a DAC or dedicated preamp) is not able to drive the amplifier, and potentially incur damage due to the characteristic impedance being too low. 

Those with more esoteric designs in DACS, i.e. NOS DACs, and preamps should exercise caution and understand the limitations of their gear, and accept the potential for damage if they proceed. At this point in time caution is still to be exercised as regards types of systems in which this can be done safely. 

Doug I have been thinking of puttting this thread, 2weeks ago, and Iam glad You and Tara’s chime in for more clarifications and information..I believe only few are aware about the double ic...

Is this similar to "Shotgun" with speaker cable?  If so, the improvement should be quite audible.