XLR or RCA?

XLR balanced low impedence cable signals can run 100s of feet with ZERO noise.

Jmcgrogan2: please direct message me your address, and I will send you a sweet record.

My experience has been that if the equipment is fully differential, properly implemented, an XLR cable is a real bonus as the cable is sonically transparent. I've run some very good RCA cables, and in one application where the output of the source and input were fully differential, I could find no meaningful difference between a set of Mogami cables and anything of any price upwards of $1K. And I set that limit of $1K not because I think cables above that can beat the Mogami, it's that I just have no interest in spending more on cables.

And as noted, just because there's an XLR output doesn't mean it's better. I have a Pass Aleph Ono phono stage and I asked the kind folks at Pass which I should use into my Pass INT-150. The answer was- use the RCA

XLR any day for me. In my system, when used between my preamp and mono amps, it eliminates hum which is ever present when i use RCA cables.

Yes, you are right, full benefit is obtained if the system entirely is wired using XLR

I used a new pair of balanced cables into a decidedly non balanced but XLR friendly power amp, and they sounded like crap. Seriously...replaced them with much better XLR cables and all is well (although in this case I could be using single ended cables I do prefer the XLRs anyway). I noticed some substantial differences between brands of ACTUALLY balanced cables when mixing sound with headphones from a live feed (TV show production). Even with truly balanced signals I can say that better cables can sound much better. Who knew?