Many years back, I saw a photo of Billy Gibbons performing in the early 70s standing in front of the his Marshall “Rio Grande” stacks. They had replaced the Marshall knobs with chicken head style where I could clearly see his settings. I made note of it and went straight home and tried it on my ‘71 Lead 50 into my slant cab with G12M-25s. It was dead on the Fandango live Side A tone.
The settings have been engrained in the brain since. L-R:
Presence - 6
Bass - 10
Mid - 0
Treble - 0
Vol 1 - 9 (3:00)
Plugged into top bright input, channels not jumped.
Makes the amp sound like it’s about to barf. If you need a just little more midrange you can just bring it up to your liking.
Likely only works on a Lead head, Model 1987 or 1959. Haven’t tried it yet with one of my SV20s.