So I have been researching headphones and headphone amplifiers as I am unable most of the time to let my Axioms loose due to a new member of the family. (worth it by the way). But I do miss listening to my audio at reasonably high levels.

I have my headphones picked out but I can't seem to get any solid information on headphone amplifiers for home systems.

Question: Is there sufficient output on the typical home theater receiver for headphones or would an amplifier be required for optimal output? I couldn't find any specs for my Onkyo 601 with regards to the headphone output. Are these headphone amps only necessary for the pathetic output of most of today's portable machines? Or would one add significantly to a home system?