Connecting XLR cables

I have reconfigured my system and now my XLR cable from preamp to amp is too short. I have a spare XLR cable of identical quality. Can I connect the two cables together like an extension cord? Or will this cause a noticeable deterioration of the sound? (The system is pretty high end and the cables are Wasatch 105s).
Yes you can. Apart from the unsightly connection - provided the connectors are of high quality (make excellent contact) - it should sound just as good.
Shadorne is does, if the preconditions he has mentioned are met with.