I had a less desirable 4210 JCM800. I had an amp tech take out the clipping diodes and it sounded way better. Great way to get the "desirable" JCM800 at a much lower price point. While it is true that you can put Kemper profiles on a thumb drive, I suspect that the sound guys do additional tweaking. Every venue has a certain amount of natural reverb, and natural EQ profile. It wouldn't surprise me at all if they start with their saved profiles but then dial it in a bit, at least adjusting reverb and EQ a bit. Of course, it is possible that they do all additional tweaking from the P.A. and just use the dry signal coming out of the Kemper rig.