Turntable to Phono to Pre connections

m2team00 

... rca outputs on turntable, feeding a Simaudio Moon 610lp ...

Most turntables have a ground wire and separate grounds for left and right channels. That results in a balanced (perhaps more correctly, "floating") signal. The facts that the connectors are RCAs doesn't necessarily mean it's not a balanced signal.

I would experiment with sending the signal from the phono stage to the preamp with a good balanced XLR cable set and see how or if it sounds different compared to RCA. If there is an advantage I would hope it is audible.  In my setup I have RCA in from the TT to the phono stage and then I run XLR from the stage to the preamp due to the long run, over 30 feet. It sounds amazing. 

My understanding is that an RCA cable output is likely balanced if the ground wire is separate.  If it's incorporated into the cable one must assume that it is not balanced. My phono pre (Austin Audio Works) has a switch for balanced vs. unbalanced input. I don't know if there would be any benefit for running a balanced out from your preamp even if the input from the TT was unbalanced, although  guess you could always hook it up either way way and listen to it. 

This question is related to the first.  I run RCA from my VPI Prime to PsAudio phono pre, and XLR to Rogue RH5 preamp, RCA to the amp.  The RH5 has only one XLR input so I used it for phono rather than DAC reasoning that anything that lowers noise in the phono section is a good thing.  But is there any point in using XLR in the middle of a line that includes RCAs on each end? 

My Phono Pre has both outputs, usable concurrently.

I use the XLR to my Preamp, and the RCA feeds a headphone amp. This allows be to listen while the preamp is in use by other sources, or in bypass mode for TV and streaming video.