How much difference between balanced XLR and RCA

Virtually everyone agrees that XLR works best for long runs of cable (my personal preference is for XLR end to end, regardless of length -- but my DAC's are only set up for balanced in and I use single ended out and they sound very fine). If your amp is a differential amp, I'd suggest sticking with the balanced. Most amps aren't (I believe). So, I'd suggest going with the preamp that makes you happy, which presumably sounds great, regardless of RCA or XLR. Think of it this way: Almost all turntables are single ended out and many audiophiles love them!

Eandylee, a differential amp is one where each of the signals is run through it's own amplification stage: Right hot, right neutral, left hot, left neutral. This requires a very careful matching of output devices (e.g., FET's). That's my understanding but I'm not an engineer so I may have misinterpreted something along the way. In any event, they are best served by XLR cables. My phono preamp will not accept an RCA and I had to go through some very interesting cabling mods to get everything to work right.