Asus xonar hdav 1.3 deluxe RCA sound issue

[slicknessessity]

Hello,
I'm having difficulty playing sound using a pair of studio monitors. I've been fiddling around with the connections and realized that the card will turn off if there's nothing plugged in the Right (red) RCA input. If I have the red rca of the L/R rca to 3.5mm plug it comes with, I can use the other port for one of my monitors, but that wastes a slot.

Any ideas around this?

 

[sk1939]

Do your monitors have an RCA input?

 

[slicknessessity]

No. It has 1/4 TRS and XLR.

 

[sk1939]

Why don't you get two TRS to RCA cables, or am I missing something?