I recenly got the Sonorous X as NOS (by weird turn of coincidence, prior owner bought it few years ago and never opened the box).

I agree wtih pretty much all your impressions.

The biggest challenge to me, frankly, is comfort. Weight aside, the earpads have are both small and lacking any depth, so my ears (of normal size) are constantl pressed. Are the E pads any deeper or wider? or have you found another solution to that, if any? Thanks for any insight..

I promise you made a wise decision--you now have a real underrated/underappreciated gem on your hand! First of all hold onto the pristine box you have since new---as with the faux fur packaging of the original Pandora Hope VI, the ash wood is/will be worth a mint. Second, yeah, the C pads can press a little but give it some time to get used it them and it will be worth it (I think they may be for me also just used to it). Finally, run this off the best source you possibly have. Sure @ 16ohms it can run off a phone--but it wont sound it's best until sourced by high-end equipment. I sourced them from the new Cayin balanced tube DAP (N8ii) running DSD material and my audiophile friend told me it was the best "headphone sound" experience he's had in all 45years of music listening.

Thanks for the reply!

I run them off my Auris Nirvana amp, that is connected to my Bricast M3 DAC, which is fed from my Roon server (wired ethernet). It's a really great chain that I use with several great headphones.

Good to know about the ash wood. Didn't realize that's a thing..

I actually just ordered some pads from ZMF that are for Beyer which I hope will fit. I've used their pads on both their headphones and moded others with great results. I'm hoping for a lucky break in fit. The current pad deapth is a real issue for me in terms of comfort.

You certainly have the source you need. Try to make those C pads work if you can. I picked up both C and E pads from the US distributor and the 3-layer C are far superior--if not a royal PIA to install. I'm not sure what replacements would be like but these are custom designed for it. The original ones on the X were supposedly nicer and i hear more comfortable, but the C sound superior. One more thing---this H/P probably needs 150 hours of break-on to sound it's best. See if you can run it on a loop over the weekend next weekend with the "C" pads maybe on a wood headphone stand--then listen to them again. I will try them again tonight after just loading up a 1TB SD card for my DAP and will pay special attention to the pad feel...curious now.