XLR to RCA plugs or cable

Both Cardas adapters are great. No sonic difference with the clear adapters. I have 2 sets in the system. RCA phono into XLR preamp and preamp out into RCA amp. I tried the cheap ones and they did alter the sound.

Do you mean Neutrik? 

I recently bought (and returned) the premium (~$200/pr) Cardas XLR-to-RCA adapters that I had hoped would perform the same function as the OP describes. Turns out the Cardas adapters are wired internally to join Pin 2 and Pin 3 together. The result for me was no sound whatsoever. In an XLR, the two signal conductors (Pin 2 and  Pin 3), when joined together, cancel the signal completely! Why Cardas does this is beyond me…

I have the Cardas that I am not using and a Benchmark RCA to XLR cable (reverse also available) from my Benchmark DAC3B to my RAAL VM-1a headphone amp. It sounds the same as my Audience AU24 SE XLR to XLR from the same DAC3B to my VM-1a amp. A pleasant surprise since the Benchmark cable cost very little.

The Cardas sounds OK too, but I feel that there are more connection points using the Cardas. While the Benchmark is just a single cable.

One thing to keep in mind is that RCA inputs prefer to see an unbalanced consumer -10 dB level. Most balanced XLR levels are at bare minimum +4 dB output. Without stepping down that level, it’s possible you could overload the RCA input, not to mention creating some nasty ground loops, by using a simple XLR to RCA converter cable. The more correct way to do this is with a passive step down isolating transformer device; like the Jensen PC-2XR.

PC-2XR

The Ebtech Line Level Shifter accomplishes the same task for a cheaper price (and still has a ruler flat frequency response). With the Ebtech however, you have to use a 1/4" TS (tip/sleeve) cable to RCA, instead of an RCA to RCA like on the Jensen model.

Ebtech LLS-2-XLR Line Level Shifter

Are there no RCA output jacks on the phono stage? If there are, exactly what are you trying to accomplish here by using the XLR outputs?