Yesterday my rehearsal with my (very ) loud band confirmed a bit, what musicman65 predicted:
You can't run an SS amp into saturation without creating square waves and ugly harmonics so you need extra headroom to avoid this.
Possible that only one Jensen Blackbird speaker is not enough for these volumes. So when I set the UNLEASH to the max it was quite harsh yesterday. With a second cabinet in parallel the total impedance would drop to 4 Ohms so that the UNLEASH would fire out nominally 180 Watts. This and the fact that there would be less burdon on each speaker might be a cure for this effect. ... Time will tell ...
If you play in a club or on smaller stages (probably like fretboardminer) and maybe the amp is not even miked up, you will get a good guitar-sound with a simple tube-amp very fast. If you want to have the same quality with the KPA you need very good FRFR-cabs.
I have a RCF NX 12sma and a RCF TT08 here. Yes, for really small gigs a combo is still unbeatable (at least now with the UNLEASH for controling the volume). On larger stages all the features of the KEMPER are very enticing. I think I will soon sell those FRFR speakers. But not the KEMPER. There are a few things I have to check out first.