Possible. Keep in mind that balanced XLR connections have two central conductors rather than the one in a coaxial cable. They work by sending out two signals, with one inverted 180 degrees in polarity, which are then in effect "re-inverted" in a balanced receiving unit(i.e., the amplifier). It's unlikely this this is the basis for the problem if you didn't notice a deterioration when you first used the XLRs, but in any case try it with the coaxials back in.

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Enjoy the music, not the equipment.