Chad:
My gear is all un-balanced so I cannot address your XLR question. However, below is a quote from member Nsgarch, which may still be buried somewhere in the archives:
"It is customary to short any unused RCA inputs on preamps. This prevents pops and clicks when switching your source selector between actual sources that are plugged in. Also prevents unused inputs picking up stray RFI. You can use pre-made shorting plugs or make them yourself. I don't recommend the Cardas caps because they don't actually short the input, but only shield the hot signal socket from RFI.
Unused XLR inputs do not require this treatment since they are balanced and self-cancel any noise."
My gear is all un-balanced so I cannot address your XLR question. However, below is a quote from member Nsgarch, which may still be buried somewhere in the archives:
"It is customary to short any unused RCA inputs on preamps. This prevents pops and clicks when switching your source selector between actual sources that are plugged in. Also prevents unused inputs picking up stray RFI. You can use pre-made shorting plugs or make them yourself. I don't recommend the Cardas caps because they don't actually short the input, but only shield the hot signal socket from RFI.
Unused XLR inputs do not require this treatment since they are balanced and self-cancel any noise."