"Anyhow, these tubes are loud and proud! There is little doubt this tube is not for Blues or Jazz...for a modern amp design."
The problem I had with the 6L6-CHP in my experience with my old but high gain Mesa .50 Caliber plus, was a seriously over-brittle tone, as well a secondary sizzley-tone in the background. I was using a single EVM12-L at the time, so this is not a speaker "color" issue.
My buddy with the other half of quartet says they sound great in his Fender, but he is NOT a tone junky.