I have a logitech z906 500w 5.1 speakers, the IO on the rear of the speakers supports surround L, Surround R, and center. As is standard, see link for comparison () I have the RCA cables connected to the system, along with the Analog 7.1. I can get sound out of the RCA cables not problem when the correct selection on the speakers is made (selection 2). Thought when I tried to get sound out of the 7.1 set up I get nothing (selection1)??? Yes I have ensured that the correct selections are made on the speakers. I have used the toslink connection too, and had to adjust the sample rate to get sound. I am lost on how to get the true 7.1/5.1 surround sound to work. I have tried disconnecting the RCA out, and rebooting the system. I have uninstalled and reinstalled the software. I have changed the order of which the cards are installed in the PCIE slots, I have even tried different mother boards. Yes the cards are connected via the supplied cable and yes primary card has been powered through out all the testing. I am open to any and all suggestions. I fear that the 7.1 card that I received may be defective. 

I have the 3 pair color coded and matching from card to speakers input.///  I really need a way to check the output of the 7.1 card other then the speakers I currently have., or the input of the speaker for that port.
 

MhzManiac
Should be able to plug in a cheap pair of headphones directly into each of the card's output jacks and run the sound test to test for each channel. Also double check what your windows sound control panel has setup for your sound card. Might be overriding your settings.

I will try that in the A.M. and give feed back. Thank you

This is the fix
from Jeff Holden @ logitech product z906 for true 7.1/5.1 feed back from the EVGA NU Audio card.

Interesting fix.