Hell yes they scale!
Normally I keep headphones to strictly digital media, and 2ch to just vinyl, but not long ago I hooked up my Headroom Maxed Balanced Home w/ HD650 to the big 2ch to help track down a grounding issue.
That was 110 lbs. of turntable and a Koetsu Platinum cartridge feeding into the HD650, haha. Wow! Definitely the best I've heard HD650. They keep scaling! I have half a mind to hook it up again sometime just for listening pleasure. Though the ATH-L3000 "Leatherhead" and Stax SR-009 are still my favorite headphones overall, cost no object.
