I wasn't really a fan of your "smoke" series (just personal taste) but I really like this Manfred. One question and one personal and probably irrelevant aside: did you shoot this with the D810 too - just so we could compare? And maybe I like it because before we downsized our living accommodation I had many happy hours of music played through a valve amp!
Bill - At this point I am still too busy trying to figure the camera / lenses out. Once I am comfortable that I am getting the best results, I plan on comparing the two cameras. That is unlikely to occur for another month or so.
I suspect that the differences are likely to show up on large prints, as the images I post here are about 2MP in the sRGB colour space. I effectively throw away a lot of data from both cameras, as well as a lot of colour data in the posts.
In terms of tubes / valves I remember how long it took for the radio or television to warm up, when I was a child. The television repair main would spend a lot of time removing and replacing the tubes when the TV was not working.