Seeking recommendations for DAC to amplifier balanced XLR cable

On a related note. RME makes available bit test files for devices sending digital output to the ADI-2 DACs. I copied these files to a USB stick, put it in Bluesound Node2i which now serves as my network transport and "played" them on the RME ADI-2. I played them on both (MUTEC) Toslink optical cable, and Mogami 2964 coaxial. All tests pass! -- except 32 bit samples as S/PDIF transmits "only" up to 24 bit (this is as expected). This means Node2i works perfectly and so do both inexpensive cables (this Toslink is about $6; coaxial was $45 but only because I fancied a "nice" one, a $7 Hosa from B&H should do exactly the same trick). No fancy cables needed here.
After making sure that both optical and coaxial work perfectly, and therefore work the same, I kept the optical connection between Node2i and the RME DAC, while moving the coaxial to the digital output from my 27 year old ADCOM GCD-600 CD player (5 CD changer). I have just burned one of the test files, corresponding to Redbook (16/44) parameters onto a CD-ROM and "played" it as well -- again the test passed, so now I know that the CD passes all the WAV bits perfectly to the DAC. The DAC is therefore the heart of the system now, converting music from 1) CDs played on the old CD player, 2) streaming from Qobuz received from Node2i, 3) my FLAC files from an external disk connected to Node2i. Only one interconnect is needed, I can sell all others. Only the single balanced XLR cable, in my case Sommer Epilogue 1m) runs from the RME DAC to the MF M6si amp.
The whole system is greatly simplified, perfected, and (bit) tested. It is not very expensive, either. And, I might add, sounds real nice :-)

Perhaps check these out. I like them. Give Mark a shout, he can make a set for you. https://www.audiogon.com/listings/lis9af99-black-shadow-xlr-1-pair-1-meter-xlr-ic-s-interconnects?sh...

BTW, do you think that the AZ can still improve anything? Is it worth the effort/cost?

As I’m totally unfamiliar with the Sommer interconnect I really have no idea if the AZ would yield any improvements.  I would say that if you haven’t had the opportunity to hear many interconnects in your system it’s always worthwhile to hear some others for perspective if nothing else.  I’ve heard several interconnects in my system and the AZ Silver Refs are very good all-rounders, which you probably already know having read some reviews.  So if you do try them and don’t notice any meaningful improvements you’ll have some peace of mind that you’re in very good shape and can put interconnects out of your mind for a long time.  Since wires are relatively easy to try used with little risk I think it’s well worth the effort, again at least for perspective if nothing else, but that’s me.  In any event, have fun listening to and enjoying your new improvements. 

This is Sommer Epilogue:
https://shop.sommercable.com/en/Cable/HiFi-Home/NF-Phonokabel-Stereo-Paar-Epilogue-QuadCore-HighEnd-EPB1.html

Matthias Carstens, the designer of the RME ADI-2 DAC said on his forum:

XLR cabling has several benefits - no ground loops, better SNR, lower noise sensitivity. The quality of these cables does not matter much and they are not expensive, so go for them.

Balanced cables are designed to cancel out noise. This relatively inexpensive Sommer Epilogue in the XLR configuration sounds no worse than AQ Colorado in RCA. At this point I have doubts if messing up with cables is going to make any further improvement -- but, if I could try-before-buy, I am open to experimentation.
 

After 4 more weeks with Sommer Epilogue XLR we compared it to Audioquest Colorado RCA which I had been using previously. Please not that we are not comparing apples to apples because Sommer is balanced. Finding number 1: the two cables are pretty much exchangeable, it is very hard to tell the difference. But Sommer is around $100, while the AQ Colorado was $450, 50% off list $900. A total waste of money. Finding number 2: if really hard pressed, I'd prefer the Sommer XLR to the Colorado. This can mean, however, that XLR is preferable between RME ADI-2 DAC and MF M6si.