Here is my HD800 Response graph for #20521:
I thought I would add another one to the forum's collection.
S/N 4380 checking in...I bought them as "factory refurbished" from a local shop last May and they sound fantastic. Not sure what exactly was refurbished so I could have newer drivers or maybe not. Either way, I heard them (only pair they had) and had to have them.
I am listening to them with my speaker amp through speaker taps right now and they sound even more fantabulous.
+1 on the Stratus/HD800. No need to worry too much about serial numbers, mods, or cables. Just plug and play.
Took a peak at it and before I spend that much... I think I would DIY. IMHO when you start to get into point to point wired gear... tweaking to your preference is key. Are there any circuit board designed amps out there that are even in the same ballpark as this amp?
For me recently it is the F3 from First Watt. I am running it off speaker tops. Awesome bass extent ion and really even presentation across freq range.However currently the Stratus looks super appealing. As well as the GS-X mk2 -- having the preamp option on that one is a nice bonus.