Also approaching 50. I'd have bought the HD600 or HD650, but I still have these old Sennheiser HD580s, and they're just as comfortable and sound pretty darn goo

Also approaching 50. I'd have bought the HD600 or HD650, but I still have these old Sennheiser HD580s, and they're just as comfortable and sound pretty darn good. As for amp, I still have an almost 20 year old NAD receiver, and the headphone output of that is still the best sounding headphone amp I've ever heard, flat out.