Are you using an attenuator or are these loud tube amps that you're talking about?
First, unfortunately, I don't use these amps much as they're loud as F*** at their sweet spot. (It's why I have the Kemper)I did build and install a Variable Voltage Regulator (VVR) circuit in my AC30 which is kind of an attenuator. But what I'm saying is old amps don't have a master volume control, so no Gain, drive, or preamp knob. They’re clean amps, you have to turn the volume up to get overdrive. So, the "Gain" knob on the Kemper for a bassman, or Deluxe Reverb, or AC30 would be the profiled amp's volume knob? Those amps sound great with the volume down low and they’re clean, AND in the middle with just a bit of breakup, the AND with the volume way up distorting the tubes. With that though the actual volume goes way, way, painfully up. That right now would require three separate profiles. But on the amp, the only knob you would have touched is the one volume knob. The Kemper cannot work that way because those amps don't have a distortion knob, where the output volume stays the same but the overdrive goes up. Would the "gain" knob simulate what the volume knob does, but without actual volume? But to do that it would be a "modeled" gain, overdrive(whatever you call it) It would no longer be a Profile of the actual gain of that amp at that volume? Wouldn't the profile be a better example of the amp not a simulated/model of the sweep of the volume pot? That after all is why WE feel profiling sounds better. Right?