I thought plugging my headphones into a receiver would be a way to test how much better they might sound with an amp. But apparently - NOOO! This article on HeadWize says most receiver headphone jacks are about 10-20mW - which means no more amperage than my IRiver 320 portable MP3 player, and less than an IPOD in terms of mW. "And this is exactly what you find in hi-fi receivers. Their headphone jacks typically provide only 10-20 mW of output Power." http://headwize.com/tech/dbohn1_tech.htm Am I misunderstanding this article? Am I confusing amps and wattage? My Onkyo receiver (501 I think) has no rating in the booklet about watts from the headphone jack.