I recently rebuilt a Sansui AU-5500 amplifier. I was testing it when I realized it was getting late and not wanting to **** my long-suffering neighbors off too much I dug out the old Sennheiser HD-570s that I haven't used for a long time. (Years) Wow! is the best description I can give, I didn't realize/remember just how good these things were? I realize there are better models but these did a very good job all the same!