Same experience here. We played a jazz/blues gig (quartet) in a bar a couple of weeks ago. The place was small and we had to keep volume low so I've taken just my old, trusty Marshall Keyboard Amp (50W SS, made in '88 ) for monitoring. At the end of the show another (old) player comes to me to congratulate for the sound and to say that "nothing can substitute a good old tube amp for tone, BTW...what is that funny stuff on top of it?". You should have seen his face when I told him the truth...
Hilarious!!