Running balanced. Difference between XLR vs. RCA.

A piece of gear might be internally balanced (or not), but any gear can only offer balanced connection on XLR-terminated, internally-balanced cables (though not all gear offering XLR connectors actually provides balanced output and/or input!). RCA-terminated cables (and I/O jacks) are inherently single-ended in operation, although it's possible that a cable itself may be capable of carrying a true-balanced signal if it was to be reterminated with XLR connectors (not always the case, though - it depends on the cable design). If your gear has true internally-balanced construction (in other words, has duplicate + and - signal paths from input to output), then it will offer true-balanced output and/or input on the XLR jacks, and you would probably be shortchanging the sound not to avail yourself of balanced connection, so try some XLR-terminated, internally-balanced-construction cables. Even at the 1-meter cable length, if you don't automatically get an audible benefit from the balanced cable itself, it is likely that your gear will operate more transparently if you don't feed it a single-ended signal, because it must be internally converted into a balanced signal prior to the balanced circuitry, thereby adding an unecessary active stage to the gear's operation when employing the RCA jacks. BTW, if you plan on doing head-to-head auditions of RCA and XLR versions of the same cable in your system, just make sure to account for the fact that balanced analog connections will usually give a result about 3dB 'hotter' than the single-ended option, thus requiring that you adjust the volume control to achieve matched levels in order to perform fair sonic comparisions - otherwise, the ear will always favor the slightly louder balanced connection, skewing the test.

An experience on the question of whether balanced connection can make a difference with shorter cable runs: Between my balanced DAC and balanced preamp, I experimented by trying 1m runs of two different cable types in both balanced XLR and single-ended RCA configurations for each type, and for both types, the balanced XLR examples proved superior (with volume levels compensated to match - the preamp allows for input-level offsets to be pre-programmed to within .1dB for accurate comparisions, which I remotely switched from the listening chair). In particular, running the balanced connection resulted in a presentation that was more dimensionally 'embodied', with fuller tonal saturation and dynamic contrast. These differences were slight but consistent, and musically worthwhile; the effect in balanced mode was unmistakably a bit more believable and engaging overall. So I can confidently say that short run length by itself ought not dissuade anyone from trying out balanced connection, especially with true-balanced components, but as Albert and others have noted above, everything is dependent, and YMMV. You just have to do the audition for yourself...