those are some pretty drastic measures, that shoudn't be necessary at all to get a accurate profile. I'm still convinced that something odd is going on there.
I thought so too, but the other Hellcat clip I posted, "Hellcat red", is the "Conford Hellcat Red" profile from Einar Nysted on the rig exchange. And when the gain is matched to the profiles I ran (7.5), it exhibits the exact same issue. So I'm inclined to think this is just the way it is with my amp. Of course, if you aren't recording test clips and A/Bing, you'd probably never notice.
I'm sure this varies amp to amp. I downloaded some Engls off the exchange, and they sound pretty clean. But those amps are famous for their extreme bass tightness at high gain -- it's almost as though they are internally high-passed. So they probably profile well.
Nevertheless if anyone else owns a Hellcat and wants to run a few profiles on the red channel at max gain, that would be interesting to compare.
Anyway, fascinating device, and a learning experience to boot!