Well I just grabbed a used pair of HD-6XX off r/AVexchange. They sound awesome through my SMSL iDEA dongle DAC, but I’m not very impressed with their build quality. My Final Sonorous III’s are waaaay better. Are 650s built better than the 6XX? I guess I was just expecting more.
In any case it doesn’t matter that much to me since the sound good. I expect they’ll sound even better when my Schiit Midgard and Modius arrive in the next couple day.
They are well built it’s all plastic but good durable plastic the plastic on 6xx feels a little cheap but it’s high quality and durable. Any of 6x0 will be very durable and long lasting.