I like my HD650.  I have always liked the Sennheiser sonic signature and I was immediately impressed after using the HD555 for a couple of years   But then after awhile; after some A/B comparisons I heard the famous HD650 veil.  There seemed to be less treble response than the HD555.  Yes there was definitely more detail and Bass, but after A/Bing with the HD555, I became a bit annoyed. My parents have a cheap triple port headphone amp connected to the TV for $40.  When I connected the HD650 to it, there was no treble response.  This is where...