If your preamp and amp are both fully differential balanced, then running
balanced from your source will likely sound best due to a lower noise floor.
However, if either your preamp or amp are not fully differential balanced, then
there may be little sonic difference between the XLR and RCA outputs on your
source (there may be little difference anyway...).
The best suggestion is to try both ways if you have the cabling to do so (same
brand and model of interconnect).
balanced from your source will likely sound best due to a lower noise floor.
However, if either your preamp or amp are not fully differential balanced, then
there may be little sonic difference between the XLR and RCA outputs on your
source (there may be little difference anyway...).
The best suggestion is to try both ways if you have the cabling to do so (same
brand and model of interconnect).
