I can tell the difference between colors of the same tube type. I am surprised that some cannot.
Sure the green coded STR445 sounded good at a close bedroom level. Just that slight turn on the channel master did not take much to get to gig levels. 9am setting is near gig level. 9:30am to 10am is nuts. Just what I noticed with the first Mark VII that came equipped with the greens, I found it less desirable and muddy at gig level. It does not take much to make a difference. Those greens I have may be closer to grey. They sounded great in the Badlander and not so bad in the JP2C. Just thought they seemed too much for the Mark VII. I could revisit those again as I have two Mark VII. I can do a side by side comparison as this has sparked my curiosity to find out how different they are. When I was exploring the tube colors, it was before I got the second Mark VII. At that time I was comparing the Mark VII to the JP2C when I noticed the greens in the Mark VII did not sound as satisfying. Note: I strive for the most aggressive grind characteristics. I was not getting that with the greens, as it was more muddy and less detailed. The yellows made a difference that sounded on par with the JP2C (this amp requires greens or grey, running the yellow or red it goes lame).