So,
he does say that the KT66s have an inherent property that gives them some potential looseness. That would also explain why my JTM clone with EL34s doesn’t seem to have the issue. I wasn’t entirely wrong in shaking my fist at the KT66s.
Knowing this, I can work with it.
I generally don’t use humbuckers, the boomy bottom is less with single coils but it’s still there to the point that the neck pickup isn’t useful. The Body control does help a lot but not completely.
Oh, I wouldn’t say I’m trying to get a modern metal tone. That’s not my style.
I definitely have been experimenting with speakers. The only ones that didn’t do well so far have been the G12C, which were thin sounding. Perhaps they were designed that way to deal with the loose bottom in the amp. Vintage 30s is the answer to that question.
My permanent solution was to change C4 from 220μF to 47μF. Which may have gone a bit far maybe a 150μF would be better but I’m pleased with the change.
Thank you for all your advice.
