Just be wary with those adapters with certain amps that use split ground planes you will damage your amp using an adapter like that. It is better to use an XLR -> speaker tap adapter to be on the safe side. The Emotiva uses a shared plane as far as I aware so there it should be fine.
Tbh, you should have enough knowledge of speaker amplifiers, to the point of understanding if yours has a shared ground, before attaching headphones to them.
+1. Safest route to go is the HE-adapter and their 4 pin xlr cable. That will run you $250. Otherwise I've seen this: http://www.ttvjaudio.com/Banana_to_1_4_Headphone_Jack_adapter_p/the0000005.htm
Wow! That's pretty expensive!